VACUUM FURNACES TECHNICAL CONTENT Archives

IN 718 Part 1: History, Applications, and Production

Today’s Technical Tuesday highlights this first installment in a multi-part series by Nikolai Alexander and The Heat Treat Doctor® Daniel H. Herring, which introduces Inconel® Alloy 718, one of the most widely used nickel-based superalloys, tracing its history, applications, and production fundamentals. Understanding why this alloy performs so well in extreme environments is critical as manufacturers consider material choices available for demanding components, especially alloys more typically sourced outside of one’s own industry. As demanding performance capabilities are being required of new engineered solutions, selecting the right alloy becomes a strategic decision to meet the need for higher temperatures, pressures, and corrosive environments.

This informative piece is from Heat Treat Today’s February 2026 Annual Air & Atmosphere Heat Treating print edition.

History

Inconel® Alloy 718 (IN 718) is a nickel-iron base superalloy known for its exceptional strength, resistance to high temperatures and ability to withstand harsh environments, where oxidation, creep, and corrosion resistance are paramount. The alloy was created by Dr. Herbert L. Eiselstein, who began his research in 1958, culminating in a patent assigned to The International Nickel Company in 1962 (U.S. Patent No. 3,046,108). In the many years since its creation, IN 718 remains the most widely used of all superalloys due to its availability in both wrought and cast products with high strength and stress-rupture life up to 650°C (1200°F), good hot working characteristics, castability, weldability, and cost effectiveness — all in an alloy with nominally 18% iron! The alloy’s superior performance is due in large part to its unique strengthening mechanisms.

There are different classifications of a superalloy, all based around the predominant metal present in the alloy. These categories include (Akca and Gursel 2015):

Nickel-based
Iron-based
Cobalt-based

The microstructural design makes IN 718 one of the best alloys for service applications below 650°C (1200°F) (Loria 1988, Herring 2011). It is widely used in extreme environments where components are subjected to high temperature, pressure, and/or mechanical loads. When heated, IN 718 forms a thick, stable, passivating oxide layer that protects the surface from further attack.

The alloy retains strength over a wide temperature range, making it attractive for high-temperature applications where materials like aluminum and steel would fail due to creep caused by thermally induced crystal vacancies. Inconel’s high-temperature strength is developed through heat treatment by solutionizing and precipitation hardening.

IN 718 is an alloy used around the world, but you might know it better by one of a variety of trade names (see sidebar).

The alloy has been modified numerous times to extend its operating temperature and service life. The alloy is readily available in all of these modified variations, each having slight differences in chemistry, cast and wrought processing methods, and heat treatments.

Applications

There is a wide variety of IN 718 applications across many industries, including aerospace, nuclear, oil and gas, automotive, motorsport, chemical processing, non-nuclear power generation, medical, tooling and molds, and fire protection systems.

In the automotive and motorsport industry, IN 718 is used for turbocharger rotors, exhaust manifolds, and valve springs in high-performance engines, such as those found in Formula 1 or the 24 Hours of Le Mans race cars. Naval warships are also purported to use IN 718 for components in their nuclear reactors (Table A).

Table A. Possible Uses of IN 718 in Naval Warship Nuclear Reactors

Table B. Oil & Gas Industry Use Examples for IN 718

Figure 1. A “Christmas tree”: the complex assembly of valves, gauges, and controls installed at the surface of a completed oil or gas well which has the primary function of regulating and controlling the flow of oil from the well. | Image Credit: Croft Systems

Perhaps surprisingly, IN 718 is also widely used in the oil and gas industry, which in addition to its many other benefits has remarkable resistance to sulfide and chlorine stress corrosion cracking at both high and low temperatures (Table B). Stress corrosion cracking is a failure mechanism that is caused by a combination of environment, a susceptible material, and the presence of tensile stress. Oil and gas applications like downhole tools, wellhead components, and subsea equipment benefit from IN 718’s other valuable properties as well, some of which include:

High strength and toughness at temperatures up to 700°C (1290°F)
Excellent resistance to pitting, crevice corrosion, and stress corrosion cracking
Sustained strength in hydrogen sulfide (H₂S) and CO₂-rich environments
Good weldability and fabrication

Continuous innovations in processing and material chemistry have enhanced superalloy properties resulting in the extension of its use into other industries, such as the energy and more conventional transportation sectors (Loria 1988).

Production Methods

IN 718 is available in cast and wrought alloy form and follows a stringent production process (Figure 2). Basic melt practices are used, such as vacuum induction melting (VIM), vacuum arc remelting (VAR), and electro-slag remelting (ESR).

Figure 2. Flow diagram of processes widely used to produce superalloys (Data reference: Akca and Gursel 2015)

VIM

The VIM process produces liquid metal under vacuum in an induction-heated crucible. It is used as a primary melting step in the route to producing wrought and cast products. Before being melted, the raw material can be refined and purified, and its composition can be controlled. VIM has been widely used in the manufacture of all types of superalloys, which must be melted under vacuum or in an inert gas atmosphere because of their reactivity with atmospheric oxygen and nitrogen.

VAR

The VAR process, a secondary melting technique, converts VIM-processed electrodes into ingots whose chemical and physical homogeneity have been significantly improved. In this process, a stub is welded to one end of an electrode, which is then suspended over a water-cooled copper crucible. Next, an arc is struck between the end of the electrode and the crucible bottom. Maintaining the arc generates the heat required to melt the electrode, which drips into the crucible and can subsequently be poured into molds. Many inclusions can be removed by flotation or chemical and physical processes before the molten material solidifies.

ESR

The ESR process, another secondary melting technique, is similar to the VAR process, but with notable differences. Remelting does not occur by striking an arc under vacuum. Instead, an ingot is built up in a water-cooled mold by melting a consumable electrode that is immersed in a slag, which is superheated by means of resistance heating. Rather than operating in a vacuum, the process is conducted in air under the molten slag. During melting, metal droplets fall through the molten slag, and chemical reactions reduce sulfur and nonmetallic inclusions. Both ESR and VAR processes allow directional solidification of an ingot from bottom to top, yielding high density and homogeneity in its macrostructure, as well as an absence of segregation and shrinkage cavities.

Casting Methods

IN 718 can also be produced by several casting methods. The most common of these are investment casting and (vacuum) die casting:

Investment casting: This process involves creating a wax pattern, coating it with a ceramic shell, melting out the wax, and then pouring molten IN 718 into the ceramic mold.
Vacuum die casting: This method uses a vacuum to fill the mold, resulting in a refined grain structure, minimal porosity, and good dimensional reproducibility, making it suitable for components like airfoils.
Sand casting: This method is far less common due to its inherent limitations in precision and surface finish, but the technology has been used for large castings.

A Metallurgical Perspective: The Role of Gamma Prime and Double Prime

IN 718 is a precipitation hardening superalloy. Its principle strengthening phases are gamma prime (γ′) or Ni3Al and gamma double prime (γ″) or Ni3Nb. The relationship between these precipitates (and others) and the gamma (γ) nickel matrix is critically important. For example, the coherency strain (i.e., the elastic deformation that occurs between two phases when their lattice structures do not perfectly match) is due to the fact that γ′ is face-centered cubic and γ″ is body centered tetragonal. In the case of IN 718, these strengthening effects are influenced more by γ″ than γ′ (ASM International 2016, Lee et al. 2023).

In addition, IN 718 has a natural tendency to precipitate rapidly by homogeneous nucleation in the noncompressible γ matrix. Depending on chemistry, γ′ volume percentage can vary over a wide range (3%–65%). Practically speaking, creep strength is proportional to volume percent over this range at temperatures between 700–980°C (1290–1800°F). As a result, the ratio of titanium to niobium/aluminum is key to hardening. High ratios imparted by niobium assure high strength at intermediate service temperatures around 600°C (1110°F). For higher service temperatures, higher aluminum content and molybdenum additions minimize the γ and γ′ mismatch, thus contributing to more stable alloys (Decker 2006, Guan et al. 2023).

Finally, the size and shape of these precipitates is important; larger precipitates enhance the strengthening effect. Key to the formation of these two precipitates is the aging treatment temperature, time, and alloy composition. According to existing research, higher aging treatment temperatures and longer times can lead to an increased amount of γ″ while extended aging coarsens the γ′ and γ″ particles, potentially leading to a reduction in strength and creep resistance. Furthermore, the composition ratios of Al, Ti, and Nb in the alloy influence the shapes of γ′ and γ″ precipitates, forming so-called co-precipitates that also affect the properties (Table C).

*SS = solid solution; + = enhancement; — = negative effect
Table C. Effect of Various Alloying Elements (Data Reference: Decker 2006)

The highest strength and hardness, coupled with reduced impact toughness, have been observed after heat treatment at 718°C (1325°F), due to an increase in the size and quantity of γ′ and γ″ precipitates.

In addition, as a result of surface analysis of Charpy bars, intergranular fracture occurs due to abundant small-sized precipitates formed within the boundary. In the case of the Charpy impact test, the absorbed energy decreases as the aging temperature increases. The formation of carbide, γ′ and γ″ precipitates can reduce the impact toughness of materials because precipitates may cause more obstacles to dislocation movement and promote crack initiation and propagation (Lee et al. 2023).

This article’s discussion continues in Heat Treat Today’s Annual Aerospace Heat Treat (March 2026) print edition to address heat treatment methods for this superalloy.

References

Akca, Enes, and Gursel, Ali. 2015. “A Review on Superalloys and IN718 Nickel-Based INCONEL Superalloy.” Periodicals of Engineering and Natural Sciences 3 (1): 15–27.

ASM International. 2016. ASM Handbook, Volume 4E: Heat Treating of Nonferrous Alloys. ASM International.

Babu, S. S., N. Raghavan, J. Raplee, S. J. Foster, C. Frederick, M. Haines, R. Dinwiddie, M. K. Kirka, A. Plotkowski, Y. Lee, and R. R. Dehoff. 2018. “Additive Manufacturing of Nickel Superalloys: Opportunities for Innovation and Challenges Related to Qualification.” The Minerals, Metals & Materials Society and ASM International: 3764–3780.

Bradley, Elihu F., ed. 1988. Superalloys: A Technical Guide. ASM International.

Chandler, Harry, ed. 1996. Heat Treater’s Guide: Practices and Procedures for Nonferrous Alloys. ASM International.

Croft Systems. n.d. “The Difference between a Wellhead & Christmas Tree.” https://www.croftsystems.net/oil-gas-blog/the-difference-between-a-wellhead-christmas-tree/

Decker, R. F. 2006. “The Evolution of Wrought Age-Hardenable Superalloy.” Journal of The Minerals, Metals & Materials Society, September: 32–36.

del Bosque, Antonio, Fernández-Arias, Pablo, and Vergara, Diego. 2025. “Advances in the Additive Manufacturing of Superalloys.” Journal of Manufacturing and Materials Processing 9 (215): 1–31.

Eliasen, K. M., T. L. Christiansen, and M. A. J. Somers. 2010. “Low-Temperature Gaseous Nitriding of Ni-Based Superalloys.” Surface Engineering 26 (4): 248–255.

Guan, Hao, Wenxiang Jiang, Junxia Lu, Yuefie Zhang, and Ze Zhang. 2023. “Precipitation of δ Phase in Inconel 718 Superalloy: The Role of Grain Boundary and Plastic Deformation.” Materials Today Communications 36 (August).

Herring, Daniel H. 2011. “Stress Corrosion Cracking.” Industrial Heating, October: 22–24.

Herring, Daniel H. 2012. Vacuum Heat Treating: Principles, Practices, Applications. BNP Media II, LLC.

Herring, Daniel H. 2019. “The Heat Treatment of Inconel 718.” Industrial Heating, June: 12–14.

Lee, Gang Ho, Ang Ho, Minha Park, Byoungkoo Kim, Jong Bae Jeon, Sanghoon Noh, and Byung Jun Kim. 2023. “Evaluation of Precipitation Phase and Mechanical Properties According to Aging Heat Treatment Temperature of Inconel 718.” Journal of Materials Research and Technology 27 (Nov–Dec): 4157–4168. https://doi.org/10.1016/j.jmrt.2023.10.196

Lee, Shin-Chin, Shih-Hsien Chang, Tzu-Piao Tang, Hsin-Hung Ho, and Jhewn-Kuang Chen. 2006. “Improvements in the Microstructure and Tensile Properties of Inconel 718 Superalloy by HIP Treatment.” Materials Transactions 47 (11): 2877–2881.

Loria, Edward A. 1988. “The Status and Prospects of Alloy 718.” Journal of Materials, July: 36–41.

Polasani, Ajay, and Vikram V. Dabhade. 2024. “Heat Treatments of Inconel 718 Nickel-Based Superalloy: A Review.” Metals and Materials International: 1204–1231.

Sharghi-Moshtaghin, Reza, Harold Kahn, Yindong Ge, Xiaoting Gu, Farrel J. Martin, Paul M. Natishan, Arrell J. Martin, Roy J. Rayne, Gary M. Michal, Frank Ernst, and Arthur H. Heuer. 2010. “Low-Temperature Carburization of the Ni-Base Superalloy IN718: Improvements in Surface Hardness and Crevice Corrosion Resistance.” Metallurgical and Materials Transactions A 41A (August): 2022–2032. https://doi.org/10.1007/s11661-010-0299-y

Shipley, Jim. 2023. “Hot Isostatic Pressing and AM: How to Improve Product Quality and Productivity for Critical Applications.” Metal AM 9 (3).

U.S. Patent No. 3,046,108.

Acknowledgments: This paper would not have been possible without discussions, guidance and contributions from a number of individuals in both the heat treat industry and academia.

Special Note: Inconel® is a registered trademark of Special Metals Corporation group of companies.

About the Authors:

Dan Herring
“The Heat Treat Doctor®”
The HERRING GROUP

Dan Herring, who is most well known as The Heat Treat Doctor®, has been in the industry for over 50 years. He spent the first 25 years in heat treating prior to launching his consulting business, The HERRING GROUP, in 1995. His vast experience in the field includes materials science, engineering, metallurgy, equipment design, process and application specialist, and new product research. He is the author of six books and over 700 technical articles.

Nikolai Alexander Hurley
Intern
The Heat Treat Doctor®

Nikolai Alexander Hurley is a young academic, interning with The Heat Treat Doctor®.

For more information: Contact Dan at dherring@heat-treat-doctor.com.

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Ask The Heat Treat Doctor®: Why Use Partial Pressure in Vacuum Furnaces?

February 6, 2026 / HARDENING TECHNICAL CONTENT, MEDICAL HEAT TREAT TECHNICAL, VACUUM FURNACES TECHNICAL CONTENT

Ask The Heat Treat Doctor® has returned to bring sage advice to Heat Treat Today readers and to answer your questions about heat treating, brazing, sintering, and other types of thermal treatments as well as questions on metallurgy, equipment, and process-related issues. In this installment, Dan Herring explains how partial pressure atmospheres prevent evaporation and achieve bright, oxide-free parts in vacuum furnaces.

This informative piece was first released in Heat Treat Today’s December 2025 Annual Medical & Energy Heat Treat print edition.

Have questions or feedback? We’d love to hear from you — reach out to our editorial team at editor@heattreattoday.com.

Operating in vacuum can often lead to problems related to evaporation, that is, literally “boiling away” elements present in the materials being heat treated. This affects surface integrity, functionality, performance, and in some rare cases altering the chemical composition of the base (or filler) metal.

One way to overcome this problem is to introduce a gas partial pressure higher than that of the material’s vapor pressure. Different gas choices, introduction methods, and controls are available to the heat treater. The natural question is, how and when should they be used? Let’s learn more.

What is Partial Pressure?

In simplest terms, the partial pressure of a gas introduced into a vacuum furnace is the force exerted by that gas (or gases) constrained in the vacuum vessel. If only a single gas is present, the partial pressure of the system is the same as the total pressure. For a multi-gas system, air is a good example to look at. At sea level with atmospheric pressure 760 torr (760 mm Hg) and at an altitude of 3,657 m (12,000 ft), the atmospheric pressure is only 483 Torr (Table A).

Table A. Partial Pressure of Individual Gases Present in Air | Source: Jones 1997

In vacuum systems, when the chamber atmosphere is evacuated to a high enough vacuum level — commonly between 10⁻³ Torr (0.1 micron) and 10⁻⁵ Torr (0.01 microns) — issues of evaporation are likely to occur during heat up and holding at temperature. As such, nitrogen or a truly inert gas is introduced below a predetermined temperature at a controlled rate to a fixed partial pressure range and then controlled within this range. One then isolates the high vacuum portion of the pumping system and employs bypass circuitry using the mechanical pump to introduce a continuous flow of gas equal to the pumping capacity (throughput) at the required operating pressure (Figure 1 below).

Figure 1. Typical partial pressure piping on a vacuum furnace
Key:
A: Incoming gas supply line
B: Backfill line
C: Quench solenoid
D: Partial pressure line
E: Partial pressure solenoid valve
F: Partial pressure (micrometer) needle value
G: Inlet into furnace
Source: Courtesy of Vac-Aero International

Why Do We Need to Use Partial Pressure in a Vacuum Furnace?

There is no hard and fast rule for partial pressure settings used for processing various materials in the heat treat industry. However, from a practical standpoint, there are two process considerations for determining partial pressure. The first is the metal-oxide reduction partial pressure. The partial pressure of oxygen at a given temperature determines the direction of the reaction and consequently whether the part is “bright” or “discolored” (oxidized). These values are typically in the range of 10⁻⁶ Torr to 10⁻² Torr. This is why materials like titanium alloys and superalloys must be processed at extremely low vacuum levels. The second consideration is the vaporization of metal at high temperature and hard vacuum. The metal solid-to-vapor partial pressures require higher pressures to avoid alloy depletion. These higher pressures often produce sufficient dilutions of contaminants to drive the reaction to be reducing.

What is often overlooked or misunderstood is that higher levels of partial pressure “dilute” any oxygen or water vapor partial pressure but still can produce oxide free “bright” parts at higher pressures. This dilution also occurs, for example when a retort is purged with nitrogen or argon to achieve clean parts. The oxygen partial pressure is reduced by dilution rather than by vacuum. In addition, it cannot be overemphasized that oxidation present on parts from exposure to the atmosphere and moisture absorbed by the furnace lining when the door is open are critical in running clean work. Oxidation occurs on heat up, but when the temperature is high enough and conditions are right, we can reverse the oxidation reaction so the parts will clean up. This is why it is harder to bright temper than to bright harden.

In batch vacuum furnaces, combination hardening and tempering cycles are used to take advantage of the furnace configuration in which parts stay in the furnace for the full process. Often, the same parts will discolor if tempered in the same furnace after they have been removed and the furnace exposed to air.

Also, a thorough understanding of the required component properties and material characteristics (e.g. alloy composition, grain size, hardenability response) is needed to design the final vacuum heat treat cycles and select the final partial pressure settings.

Figure 2. Chromium deposits / discoloration in the area of a graphite cooling nozzle | Source: The HERRING Group, Inc

For example, stainless steels, tool steels, and more exotic alloys run in a vacuum furnace will benefit substantially from the use of partial pressure atmospheres. In most heat treat shops, partial pressure cycles begin around 760°C (1400°F) at pressure from 1–1.5 Torr (1000–1500 microns). This is primarily because chromium present in many of these materials and in our baskets/fixtures evaporates noticeably at temperatures and pressures within normal heat treatment ranges. At around 990°C (1800°F), chromium will vaporize rapidly as a function of both vacuum level and time. In general, the practical operating vacuum level for most materials is significantly above their equilibrium vapor pressures. It is also helpful at times to know the temperature at which individual elements exceed a critical (10⁻⁶ g/cm²-s) vaporization rate (Herring 2015).

In practice, heat treaters often observe greenish discoloration (chromium oxide) on the interior of their vacuum furnaces (Figure 2), the result of chromium vapor reacting with air leaking into the hot zone. Otherwise, the evaporation deposit is bright and mirror-like. To avoid these types of deposits contaminating both the furnace and the parts run in it, an operating partial pressure between 1 Torr and 5 Torr (1,000 microns to 5,000 microns) is typical for parts that will boil away their elemental constituents.

Chromium Coloration

Heat treaters should be aware that although the most common color of chromium discoloration is green, the color is dependent on chromium’s oxidation state (Table B). For example, Cr (II) compounds typically appear blue, Cr (III) compounds appear green, and Cr (VI) compounds appear orange or red.

Notes: * Most commonly observed colors
Table B. Oxidation Colors of Chromium and Chromium Compounds

Table B provides a more detailed breakdown of chromium’s oxidation states and associated colors.

Which Partial Pressure Gas(es) Can We Use?

Argon, nitrogen, and hydrogen are the most common partial pressure gases. Often, argon is preferred as it is a truly inert gas and tends to “sweep” the hot zone; that is, being a heavier molecule, it tends to reduce evaporation compared with nitrogen or hydrogen. Specialized applications, such as those in the electronics industry, may use helium or even neon (if an ionizing gas is needed). Gases having a minimum purity of 99.99% and a dew point of -60°C (-76°F) or lower should be specified.

Certain cautions are in order. For example, nitrogen may react with certain stainless steels and titanium bearing alloys resulting in surface nitriding. In the case of hydrogen, the normally near neutral vacuum atmosphere can be sharply shifted to a reducing atmosphere to prevent oxidation of sensitive process work or for furnace/fixture bakeout/cleanup cycles. Embrittlement by hydrogen is a concern for certain materials (e.g., Ti, Ta).

Figure 3. 410 stainless steel housings, hydrogen partial pressure (1,000 microns) at 1010°C (1850°F) | Source: Courtesy of Vac-Aero International, Inc

In Summary

Partial pressure atmospheres are required in many heat treating and brazing operations to achieve desired results. Introduction of the partial pressure gas into the furnace hot zone at one or more locations and controlling the partial pressure injection gas stream as a continuous flow, rather than trying to operate at a specific pressure, are critical considerations. The choice of partial pressure gas is also important both from a cost and quality standpoint.

References

Herring, Daniel H. 2014. Vacuum Heat Treatment. Vol. 1. Troy, MI: BNP Media.

Herring, Daniel H. 2015. Vacuum Heat Treatment. Vol. 2. Troy, MI: BNP Media.

Houghton, R., Jr. n.d. Private correspondence, Spectrum Thermal Processing.

Jones, W. R. 1997. “Partial Pressure Vacuum Processing – Part I and II.” Industrial Heating, September/October.

Jones, William. n.d. Private correspondence, Solar Atmospheres Inc.

Fabian, R., ed. 1993. Vacuum Technology: Practical Heat Treating and Brazing. Materials Park, OH: ASM International.

The Boeing Company. n.d. “Practical Vacuum Systems Design Course.”

About the Author

Dan Herring
“The Heat Treat Doctor”
The HERRING GROUP, Inc.

Dan Herring has been in the industry for over 50 years and has gained vast experience in fields that include materials science, engineering, metallurgy, new product research, and many other areas. He is the author of six books and over 700 technical articles.

For more information: Contact Dan at dherring@heat-treat-doctor.com.

For more information about Dan’s books: see his page at the Heat Treat Store.

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Un Giro Bienvenido: Autolimpieza en Hornos revolucionado por Sistema de Bombas Inteligentes

January 20, 2026 / AEROSPACE HEAT TREAT TECHNICAL CONTENT, VACUUM FURNACES TECHNICAL CONTENT, VACUUM PUMPS GAUGES VALVES TECHNICAL CONTENT

¿Y si su horno de vacío pudiera limpiarse automáticamente? En esta entrega de Technical Tuesday, Bob Hill, FASM, presidente de Solar Atmospheres of Western PA and Michigan, explora una revolucionaria configuración de bomba de vacío doble que elimina la necesidad de disolventes, envoltura con lámina metálica y prelimpieza manual.

Este artículo informativo se publicó por primera vez en Heat Treat Today’s December 2025 Annual Medical & Energy Heat Treat print edition. Traducido por Víctor Zacarías.

To read this article in English, click here.

Introducción

Los hornos de vacío requieren un entorno excepcionalmente limpio para procesar componentes críticos, desde dispositivos médicos hasta componentes aeroespaciales. Sin embargo, la limpieza de componentes, laboriosa y que consume mucho tiempo para garantizar la pulcritud del horno y las piezas, no tiene por qué ser necesariamente realizada por personas. Con las bombas adecuadas, su horno de vacío puede limpiarse automáticamente. Descubra cómo sería un ciclo de limpieza al vacío totalmente integrado mediante una innovadora configuración de doble bomba de vacío primario.

En el ámbito del tratamiento térmico al vacío, donde los componentes críticos suelen tener una forma casi final con una mínima o nula eliminación de material, la estética superficial del producto final es fundamental para el usuario final. En sectores como el aeroespacial, el de dispositivos médicos y el de generación de energía, el procesamiento al vacío se ha vuelto cada vez más valioso, no solo por su precisión, sino también por su capacidad para eliminar operaciones posteriores, lo que en última instancia ahorra tiempo y dinero.

Dadas estas ventajas, los clientes suelen estar dispuestos a pagar un precio premium por un trabajo limpio y brillante. Para lograr estos resultados perfectos, las empresas de tratamiento térmico al vacío exigen que las piezas recibidas estén limpias y libres de aceite. Sin embargo, lo que se considera “limpio” en un entorno de fabricación rara vez cumple con los exigentes estándares requeridos para el procesamiento térmico al vacío. Por ello, muchos tratadores térmicos adoptan medidas de limpieza secundarias para garantizar la limpieza de las piezas y proteger sus hornos de vacío de la contaminación por aceites de maquinado, lubricantes, tintas, oxidación o compuestos de pulido.

Figura 1. Horno de desengrasado al vacio. Fuente: Solar Atmospheres

Limpieza previa al tratamiento térmico: desafíos tradicionales

Antes de cualquier tratamiento térmico al vacío, los componentes deben limpiarse a fondo para eliminar contaminantes orgánicos e inorgánicos. Las prácticas habituales incluyen inmersión en disolvente, secado y desengrasado por vapor. Esta limpieza tiene como objetivo eliminar los residuos que pueden volatilizarse y depositarse dentro del horno de vacío, lo que podría comprometer la calidad de la pieza y dañar la zona caliente y la pared fría del horno.

Sin embargo, los productos de limpieza de uso común suelen ser inflamables, tóxicos, estar sujetos a regulaciones ambientales y su eliminación resulta costosa una vez empleados.

Figura 2. (Izquierda) Desengrasante de vapor y limpieza con solvente y (derecha) estación de envoltura con papel aluminio. Fuente: Solar Atmospheres

Figura 3. Como medida de protección para evitar daños en el horno por posibles contaminantes procedentes de fuentes anteriores, las piezas listas para el tratamiento térmico se envuelven en papel de aluminio. Fuente: Solar Atmospheres

Dado que las plantas de tratamiento térmico comerciales procesan piezas procedentes de miles de operaciones previas, cada una con su propio conjunto de contaminantes, la contaminación cruzada representa un riesgo significativo. El embalaje con lámina de acero inoxidable se utiliza a menudo como medida de protección, aislando las piezas del ambiente del horno. Si bien el empaque suele ser eficaz, puede ser laborioso, costoso e incluso potencialmente peligroso. Aun con el equipo de protección personal adecuado, los bordes de la lámina son extremadamente filosos. El embalaje con lámina sigue siendo una de las principales preocupaciones en materia de salud y seguridad para los empleados.

El horno para MIM: el catalizador para la innovación

Hace cinco años, Solar Atmospheres, con sede en el oeste de Pensilvania, recibió el encargo de sinterizar piezas pre-sinterizadas mediante moldeo por inyección de metal (MIM) a 1200 °C. Los aglutinantes presentes en estas piezas de armas de fuego se volatilizaron durante el proceso y contaminaron gravemente el horno de vacío, lo que ocasionó largos periodos de inactividad y mantenimiento.

Figura 4. Piezas de acero inoxidable 17-4PH brillantes y limpias tras el tratamiento térmico en un horno de desengrasado al vacío. Fuente: Solar Atmospheres

En lugar de construir una trampa fría tradicional para capturar los volátiles, el director ejecutivo, William Jones, desarrolló una solución más innovadora: una trampa caliente diseñada para desviar y capturar los contaminantes antes de que se depositaran dentro del horno. Esta adaptación proactiva ha demostrado mejorar drásticamente la calidad de las piezas, eliminando la laboriosa y frecuente limpieza de las zonas calientes y las paredes frías.

Tras finalizar ese trabajo de MIM, el horno subutilizado impulsó la experimentación. Este horno adaptado demostró un buen rendimiento con aglutinantes no deseados. Así pues, nos propusimos probar cómo adaptar este mismo sistema para eliminar impurezas de piezas de producción diaria. Tras exhaustivas pruebas con componentes no críticos de acero inoxidable grado PH, se perfeccionó un ciclo de limpieza y envejecimiento totalmente integrado, basado en vacío. Este desarrollo ha sustituido desde entonces a los costosos métodos tradicionales de prelavado y al peligroso envoltorio en aluminio, produciendo componentes aeroespaciales 17-4 PH consistentemente limpios y brillantes.

Horno de vacío autolimpiante: Cómo funciona

La innovación clave reside en una configuración de doble bomba de vacío primario.

(Izquierda) Figura 5. Sistema de bombeo de dos etapas.
(Derecha) Figura 6. Salida calefactada del sistema de bombeo n.° 1.
Fuente: Solar Atmospheres

Sistema de bombeo n.° 1: Bombeo inicial y eliminación de contaminantes:

Los componentes se cargan en el horno sin envolver ni limpiar.
Durante el bombeo inicial, solo se activa la bomba de vacío primario n.° 1.
Un aumento gradual de la temperatura permite que los contaminantes se vaporicen y salgan de la zona caliente a través de un puerto calefactado hacia la bomba n.° 1.
Los contaminantes quedan atrapados de forma segura en el aceite de la bomba, la «trampa caliente».

Sistema de bombeo n.° 2: Transición al tratamiento térmico:

Una vez completado el bombeo, se aísla la bomba n.° 1.
El sistema de bombeo n.° 2, que incluye una bomba de vacío primario, una bomba de refuerzo, una bomba de difusión y una bomba de mantenimiento, entra en funcionamiento.
A continuación, la cámara se lleva a 1 x 10⁻⁵ Torr y se inicia el ciclo térmico de vacío estándar.

Esta secuencia de bombeo en dos etapas limpia tanto las piezas como la cámara antes del tratamiento térmico sin necesidad de abrir la puerta del horno.

Resultados y beneficios

Este horno de vacío y proceso recientemente desarrollados producen lo siguiente:

Piezas más limpias: La limpieza por vacío penetra en barrenos ciegos, roscas y chaveteros con mayor eficacia que los métodos tradicionales de desengrase con solventes o vapor.
Reducción de lesiones: El proceso elimina la necesidad de envolver con lámina metálica, lo que mejora significativamente la seguridad de los empleados.
Ventajas ambientales y económicas: El proceso reduce o elimina el uso de solventes químicos, disminuye la mano de obra asociada con la limpieza previa y el embalaje, y reduce los costos de disposición de residuos peligrosos.
Mejoras en el mantenimiento del horno: Las zonas calientes y las paredes frías se mantienen impecables, sin necesidad de desmontajes semanales. El aceite de la bomba n.° 1 se cambia cada dos semanas, lo que elimina los problemas de bloqueo de la bomba de vacío debido a la contaminación del aceite.

Conclusión: Un avance revolucionario en el procesamiento al vacío

Históricamente, la limpieza de las piezas en el tratamiento térmico al vacío ha sido un desafío constante, a menudo abordado con mano de obra costosa, productos químicos y el peligroso uso de lámina de acero inoxidable o titanio para su envoltura. El innovador sistema de limpieza al vacío de doble bomba de Solar Atmospheres, integrado a la perfección con un ciclo estándar de tratamiento térmico al vacío, redefine las mejores prácticas de la industria.

Este concepto de “horno autolimpiante” no solo ofrece acabados superiores en las piezas, sino que también mejora la seguridad, reduce el impacto ambiental y disminuye los costos operativos. En un mundo donde la precisión, la limpieza y la sostenibilidad son más importantes que nunca, este avance podría crear una revolución en el procesamiento al vacío limpio.

Acerca del autor:

RObert (Bob) Hill PresidentSolar Atmospheres Michigan Source: Solar Atmospheres — Robert (Bob) Hill, FASM
Presidente
Solar Atmospheres de Western Pensilvania y Michigan
Fuente: Solar Atmospheres

Bob Hill, FASM, presidente de Solar Atmospheres de Western Pensilvania y Michigan, comenzó su carrera en Solar Atmospheres en 1995 en la planta principal ubicada en Souderton, Pensilvania. En 2000, el Sr. Hill fue designado para la puesta en marcha de la segunda planta de Solar Atmospheres, Solar Atmospheres of Western PA, en Hermitage, Pensilvania, donde se especializó en el desarrollo de tecnología de hornos de gran tamaño y procesamiento de titanio. Además, en 2009 recibió el prestigioso Titanium Achievement Award de la International Titanium Association. En 2022, Bob asumió la presidencia de su segunda planta, Solar Atmospheres de Michigan.

Para más información: Contacte con Solar Atmospheres o visite www.solaratm.com.

Un Giro Bienvenido: Autolimpieza en Hornos revolucionado por Sistema de Bombas Inteligentes Read More »

A Welcome Diversion: Smart Pump System Revolution for Self-Cleaning Furnaces

January 20, 2026 / AEROSPACE HEAT TREAT TECHNICAL CONTENT, VACUUM FURNACES TECHNICAL CONTENT, VACUUM PUMPS GAUGES VALVES TECHNICAL CONTENT

What if your vacuum furnace could clean itself? In this Technical Tuesday installment, Bob Hill, FASM, president of Solar Atmospheres of Western PA and Michigan, explores a revolutionary dual roughing pump configuration that eliminates the need for solvents, foil wrapping, and manual pre-cleaning.

This informative piece was first released in Heat Treat Today’s December 2025 Annual Medical & Energy Heat Treat print edition.

Para leer el artículo en español, haga clic aquí.

Introduction

Vacuum furnaces require an exceptionally clean environment to process critical components, from medical devices to aerospace. But laborious, time-consuming component cleaning to ensure purity of the furnace and parts does not necessarily need to be done by people. With the right pumps, your vacuum furnace can clean itself. Explore what a fully integrated, vacuum-based cleaning cycle could look like by leveraging an innovative dual roughing pump configuration.

In the vacuum heat treating world, where critical components are often near-net-shape with minimal to zero stock removal, the surface aesthetics of the final product are critical to the end user. Across industries like aerospace, medical devices, and power generation, vacuum processing has become increasingly valued — not only for its precision, but also for its ability to eliminate downstream operations, ultimately saving cost and time.

Given these benefits, clients are frequently willing to pay a premium for bright, clean work. To achieve these pristine results, vacuum heat treaters insist that incoming parts must be clean and oil-free. However, what qualifies as “clean” in a manufacturing environment rarely meets the exacting standards required for vacuum thermal processing. As a result, many commercial heat treaters adopt secondary cleaning measures to ensure part cleanliness and to protect their vacuum furnaces from contamination by machining oils, lubricants, Dykem, oxidation, or polishing compounds.

Figure 1. Vacuum degreasing furnace. Source: Solar Atmospheres

Pre-Heat Treatment Cleaning: Traditional Challenges

Before any vacuum heat treatment, components must be thoroughly cleaned to remove organic and inorganic contaminants. Common practices include solvent immersion, drying, and vapor degreasing. This cleaning step is designed to eliminate residues that can volatilize and redeposit within the vacuum furnace, potentially compromising part quality and damaging the vacuum furnace hot zone and cold wall.

However, commonly used cleaning agents are often flammable, toxic, environmentally regulated, and costly to dispose of when spent.

Figure 2. (Left) Vapor degreaser and solvent cleaning and (right) foil wrapping station. Source: Solar Atmospheres

Figure 3. As a defensive measure to prevent furnace damage from potential upstream sourced contaminants, parts ready for heating are wrapped in stainless steel foil. Source: Solar Atmospheres

Given that commercial heat treaters process parts from thousands of upstream operations, each introducing its own set of contaminants, cross-contamination becomes a significant risk. Stainless steel foil wrapping is often used as a defensive measure, isolating parts from the furnace environment. While wrapping is often effective, it can be labor-intensive, expensive, and even potentially hazardous. Even with the proper PPE, the foil edges are razor-sharp. Foil wrapping continues to be a top health and safety concern for employees.

The MIM Furnace: A Catalyst for Innovation

Five years ago, Solar Atmospheres of Western Pennsylvania was tasked with sintering pre-sintered metal injection molding (MIM) parts at 2200°F. The binders present in these firearm parts volatilized during processing and heavily contaminated the vacuum furnace, resulting in extensive downtime and maintenance.

Figure 4. Bright, clean 17-4PH stainless steel parts post heat treatment in a vacuum degreasing furnace. Source: Solar Atmospheres

Instead of constructing a traditional “cold trap” to capture volatiles, CEO William Jones developed a more innovative solution: a “hot trap” designed to divert and capture contaminants before they could deposit inside the furnace. This proactive adaptation has proven to drastically improve part quality while eliminating the laborious and frequent cleaning of hot zones and cold walls.

After that MIM job ended, the underutilized furnace prompted experimentation. This adapted furnace proved to perform well on unwanted binders. So, we set out to test how this same system could be adapted to remove impurities from everyday production parts. After extensive trials using noncritical PH-grade stainless steel components, a fully integrated, vacuum-based cleaning and aging cycle was perfected. This development has since replaced traditional expensive pre-cleaning methods and dangerous foil wrapping, producing consistently clean and bright 17-4 PH aerospace components.

The Self-Cleaning Vacuum Furnace: How It Works

The key innovation lies in a dual roughing pump configuration.

(Left) Figure 5. Two-stage pumping system. (Right) Figure 6. Heated exit port on Pumping System #1.
Source: Solar Atmospheres

Pumping System #1 — Initial Pump-Down and Contaminant Removal:

Components are loaded into the furnace unwrapped and uncleaned.
Only Roughing Pump #1 is activated during the initial pump-down.
A slow temperature ramp allows contaminants to vaporize and exit the hot zone through a heated port into Pump #1.
Contaminants are safely trapped in the pump’s oil — the “hot trap.”

Pumping System #2 — Transition to Heat Treatment:

After off gassing is complete, Pump #1 is isolated.
Pump #2 system, which includes a roughing pump, booster, diffusion, and holding pump, takes over.
The chamber is then brought to 1 x 10⁻⁵ Torr and the standard vacuum thermal cycle proceeds.

This two-stage pumping sequence cleans both the parts and the chamber prior to heat treatment without ever opening the furnace door.

Results and Benefits

This newly developed vacuum furnace and process produces the following:

Cleaner parts: Vacuum cleaning penetrates blind holes, threads, and keyways more effectively than traditional solvent or vapor degreasing methods.
Injury reduction: The process eliminates the need for hazardous foil wrapping, significantly improving employee safety.
Environmental and cost advantages: The process reduces or eliminates chemical solvent use, cuts labor associated with pre-cleaning and wrapping, and reduces hazardous waste and disposal costs.
Furnace maintenance improvements: Hot zones and cold walls remain pristine — no weekly teardowns. Pump #1 oil is changed biweekly, eliminating roughing pump seizure concerns due to contaminated oil.

Conclusion: A Breakthrough in Vacuum Processing

Historically, part cleanliness in vacuum heat treating has been a persistent challenge — one often addressed through costly labor, chemicals, and dangerous stainless steel or titanium foil wrapping. Solar Atmospheres’ innovative dual-pump vacuum cleaning system, integrated seamlessly with a standard vacuum heat treatment cycle, redefines industry best practices.

This “self-cleaning furnace” concept not only delivers superior part finishes but also enhances safety, reduces environmental impact, and cuts operating costs. In a world where precision, cleanliness, and sustainability matter more than ever, this advancement may very well create a revolution in clean vacuum processing.

About The Author:

Bob Hill, FASM, president of Solar Atmospheres of Western PA and Michigan, began his career with Solar Atmospheres in 1995 at the headquarters plant located in Souderton, Pennsylvania. In 2000, Mr. Hill was assigned the responsibility of starting Solar Atmospheres’ second plant, Solar Atmospheres of Western PA, in Hermitage, Pennsylvania, where he has specialized in the development of large furnace technology and titanium processing capabilities. Additionally, he was awarded the prestigious Titanium Achievement Award in 2009 by the International Titanium Association. In 2022, Bob became president of his second plant, Solar Atmospheres of Michigan.

For more information: Contact Solar Atmospheres or visit www.solaratm.com.

A Welcome Diversion: Smart Pump System Revolution for Self-Cleaning Furnaces Read More »

Pit LPC: A Modern Take on High Throughput Heat Treat

December 9, 2025 / CARBURIZING TECHNICAL CONTENT, MANUFACTURING HEAT TREAT TECH, VACUUM FURNACES TECHNICAL CONTENT

Producing durable, wear-resistant gears for the wind turbine industry requires exacting control of carbon diffusion. Modern low pressure carburizing (LPC) is pushing the boundaries of control and consistency. This technology fine tunes carbon diffusion into the surface of components, and applied in a new pit-style vacuum furnace, it also delivers temperature uniformity, stronger gears, and shorter cycle times for large, complex components, all while eliminating oxidation and direct CO₂ emissions. In this Technical Tuesday installment, Tom Hart, director of sales for North America at SECO/WARWICK Corporation, examines how modern LPC technology in a pit-style vacuum furnace is reshaping high-volume carburizing for today’s in-house heat treaters.

This informative piece was first released in Heat Treat Today’s November 2025 Annual Vacuum Heat Treating print edition.

The Need To Carburize

Carburizing is a thermochemical treatment that finds applications across the automotive, aviation, and energy industries, particularly in power transmission systems. The widespread use of this process across many industries stems from its ability to improve mechanical properties by enriching the surface of steel with carbon.

Consider the wind turbine industry, growing with a CAGR (compound annual growth rate) of 6.2% from 2024 to 2033 (GlobeNewswire 2024). Carburizing plays a key role in the production of gears and pinions. These components, often made of alloy steels, such as 18CrNiMo7-6, 4320, 4820, and 9310 (GearSolutions 2009, Jantara 2019), must meet high strength and quality requirements. Carburized layers, often over 4 mm thick, provide resistance to wear and dynamic loads, which is important given the turbine’s expected service life of at least twenty years.

In practice, however, gears often require servicing after five to seven years (Jantara 2019), with their failures generating long downtimes and high costs (Perumal and Rajamani 2014).

Figure 1a: Pit-LPC in a hardening cell (model)

The carburizing process, combined with hardening (usually in oil) and tempering, increases:

Surface hardness: improving abrasian resistance
Core ductility: protecting against cracks
Fatigue strength: extending the life of the part, which translates into lower operating costs

Alternative technologies, such as nitriding or surface hardening, offer other benefits (e.g., reduced deformation), but have limitations, such as thinner hardened layers, relatively long nitriding process times, or difficulties with complex geometry for surface hardening.

Pit Meets Vacuum LPC

Traditional atmospheric carburizing, despite its established position, has reached its limits in process performance expectations. In response to market needs, LPC (low pressure carburizing) technology is being increasingly implemented to enable precise process control, reduced emissions, and improved energy efficiency. More specifically, a pit furnace with vacuum heat treatment capabilities, aka the Pit-LPC, has been designed and developed to carburize thick layers on very large and/or long parts. This furnace combines the advantages of LPC technology with the ability to integrate existing hardening cells, facilitating the modernization of older installations.

While a vacuum furnace opening to an air atmosphere is a feature previously reserved for atmospheric furnaces, this innovative pit furnace has ceramic insulation and a dedicated heating system to leverage this capability. The chamber door can therefore be opened at process temperature in an air atmosphere for the direct transfer of the charge to the hardening tank. Additionally, the furnace is equipped with a closed circuit forced cooling system, which significantly shortens the charge cooling time from the carburizing temperature to the hardening temperature, increasing efficiency and shortening the production cycle.

Furthermore, the furnace allows for the process to be carried out at temperatures of 1925°F (1050°C) and higher, significantly shortening carburizing time and reducing production costs, even while maintaining a safe level of grain growth (e.g., 1800°F (980°C)).

Benefits of LPC technology designed in a pit furnace include:

Reduced process time due to higher operating temperatures
Elimination of internal oxidation (IGO) in the carburizing process
Highly uniform carburized layer
Low process gas consumption
No direct CO₂ emissions and fire risk
Ready for operation without lengthy conditioning
Computer-aided process support

Additionally, the furnace design increases work safety and comfort in its elimination of open flames, risks of explosion, and the need for constant atmospheric monitoring.

Figure 2. SimVac program window with an example LPC process simulation

This new pit furnace is compatible with SimVac software, developed by Lodz University of Technology and SECO/WARWICK, which enables the simulation and optimization of LPC parameters, reducing the need for process tests. SimVac Plus is a simulation software that includes a vacuum carburizing module (Figure 2). The program can be used either as a standalone tool for designing processes based on the desired carburized layer requirements or to visualize the effect of a given boost/diffusion sequence in the form of a carbon profile.

Testing the Furnace Characteristics and Technical Parameters

The furnace was designed to meet the highest requirements for heat treatment equipment. The basic technical parameters are as follows:

Working space / charge weight: 71″ diameter x 118″ deep / 17,600 lb (1,800 mm x 3,000mm deep / 8,000 kg)
Operating temperature: up to 2010°F (1100°C)
Heating power: 360 kW, three independent zones
Vacuum level: 10⁻² torr
Carburizing gas: acetylene

Temperature Uniformity

Temperature distribution tests were conducted in the furnace, with 12 load thermocouples arranged according to the diagram shown in Figure 2. Measurements were taken at several temperatures under vacuum conditions. The purpose of the tests was to confirm compliance with the Class 1 ±5°F (3°C) requirements of the AMS2750 standard.

Figures 3a-d. Location of the TUS load thermocouples and the results in vacuum at temperatures of 1550°F (840°C), 1800 °F (980°C), and 1925°F (1050°C)

The results presented in Figure 3 indicate that the furnace provides above-average temperature uniformity, which is particularly important for a large workspace with 71″ diameter x 118″ deep (1,800 mm diameter × 3,000 mm deep) and the processing of large-sized components with thick layers. The temperature difference (ΔT) between the extreme thermocouples, measured at 1550°F (840°C), 1800 °F (980°C), and 1925°F (1050°C), did not exceed 3.5°F (2°C). This means that the furnace meets the Class 1 requirements of the AMS2750 standard by a wide margin.

Operational Dynamics

Additionally, to evaluate the furnace’s operational dynamics, heating and cooling tests were performed on an empty device with samples. Figure 4a shows the heating curve; the furnace reaches a temperature of 1800°F (980°C) in 60 minutes. The furnace’s high energy efficiency has a heat loss of just 32 kW under these circumstances.

Figure 4b shows teh curve of cooling forced by nitrogen at atmospheric pressure, measured in three zones and on samples with diameters of 1″ (25 mm) and 4″ (100 mm). The temperature drops from 1800°F (980°C) to 575°F (300°C) in 60 minutes; reaching 210°F (100°C) takes only two hours, whereas natural cooling would take several days.

Vacuum tests show that the furnace reaches operating vacuum of 10⁻¹ hPa in under 30 minutes and has a leakage rate of 10⁻³ mbar·l/s, which meets the industry standard for vacuum furnaces.

Test of Atmosphere vs. Vacuum Carburizing Processes

To obtain a carburized layer 0.145–0.160″ (3.7–4.0 mm) thick for 52.3 HRC (550HV1), two tests were compared: one in the PEGAT atmosphere furnace (Figure 5a) and another in the Pit-LPC vacuum furnace (Figure 5b). In both cases, the charge consisted of seven gears made of 18CrNiMo7-6 material, with a total weight of approximately 6.5 tons and a surface area of 280 ft² (26 m²). The process consisted of three stages:

Stage I: heating to the carburizing temperature and soaking
Stage II: actual carburizing with cooling to the hardening temperature and holding
Stage III: hardening in an external quenching tank — identical in both processes

Table A. Atmosphere vs. Vacuum Carburizing Process Comparison

Figure 5a. Essential process data and schematic flow of the carburizing process in a PEGAT atmosphere furnace

The LPC process, which consists of saturation and diffusion segments (Figure 6) allows for the precise control of carbon distribution. As the process progresses, the duration of the diffusion segments is extended, ensuring uniform saturation of the material.

Figure 6. Vacuum carburizing process trends in the Pit-LPC

After carburizing and hardening, all components were tempered at 355°F (180°C) for three hours.

Metallurgical Results: Gears & Samples Destructive Testing

Table B. Chemical Composition of 18CrNiMo7-6 (according to EN10084)

Gears and samples made of 18CrNiMo7-6 steel were used for destructive testing, in accordance with the EN 10084 standard. Six cylindrical samples were placed throughout the workspace — inside and outside the part — to assess carburization uniformity.

Tests conducted:

Vickers microhardness (HV1): performed on a Struers Durascan 70 device, allowing for the determination of hardness profiles and carburized layer depth (ECD) — a load of 9.81 N (HV1).
Surface and core hardness (Rockwell): measurements were performed on a Wilson Wolpert TESTOR tester with a load of 1470.1 N. At least five measurements were taken for each sample.
Microstructure: assessed on a Nikon LV150 optical microscope after nital etching.
Internal oxidation (IGO): analyzed on the unetched surface of the microsection.

Figures 7a-f. Microhardness profiles after the full process (carburizing, hardening, and tempering)

Figure 7 shows the microhardness profiles for the tested samples. For each sample, microhardness paths were inspected in three cross-sections. Based on this, the effective ECD layer thickness obtained on each sample was determined, as presented in Table C.

Table C. Thickness of the Carburized Layer Read from the Microhardness Charts (effective case depth average is 0.145–0.160″ (3.7–4.0 mm) at 52.3 HRC (550 HV1))

Average ECD values obtained for the samples ranged from 0.148 to 0.154″ (3.77 to 3.91 mm).

Surface and core hardness values for all samples were consistent and typical of carburized layers (Table D). Surface hardness ranged from 61.0 to 63.2 HRC and core hardness from 39.9 to 40.7 HRC. Interestingly, samples located on the inner side of the wheel achieved slightly higher surface hardness values (caused by retained austenite and cooling intensity).

Table D. Measured values of surface hardness and core hardness

Microstructure images of low-tempered martensite, along with retained austenite, were identified, ranging from 17 to 20% (Figure 8). The amount of retained austenite was determined using NIS-Elements software. No variation in structure was observed depending on sample location.

Figure 8a. Exemplary post-processing microstructure pictures of sample 1 surface. Magnifications x100 (left) and x500 (right). Nital etching 2%. Martensite with residual austenite (approx. 18%).

The presence of intergranular oxidation (IGO) was also inspected, averaging 5.5 μm throughout the tested samples. For comparison, intergranular oxidation in the atmospheric process averages above 15 μm. In the new LPC pit furnace, internal oxidation only occurs during unloading and transfer of the charge to the hardening tank, whereas in the atmospheric furnace, the presence of oxygen in the carburizing atmosphere is also significant, significantly increasing the IGO value.

The level of hardening deformation after the process conducted in the new LPC pit furnace and the atmosphere furnace is comparable due to the use of the same hardening tank in both devices and the absence of the carburizing process.

Comparison of Process Economics

Economic aspects play a key role in modern heat and thermochemical processing. Therefore, the consumption of basic utilities was compared for the reference processes (described in Chapter 5), resulting in a 0.152″ (3.8 mm) thick hardened layer. The analysis included a Pit-LPC and a PEGAT-type atmospheric furnace, both with identical workspace and the same charge. In addition, the LPC process was simulated at 1900°F (1040°C). The results are summarized in Table E.

Table E. Comparison of utility consumption and costs

The results show that the new LPC furnace model consumes significantly less electricity by approximately 57%, which translates into a lower carbon footprint, especially when energy is derived from fossil fuels. Nitrogen consumption is comparable, with a slight advantage for the Pit-LPC (savings of up to 10%).

The largest differences are found in carburizing gases. The atmospheric furnace consumes 9,900 ft³ (280 m³) of methane — approximately 440 lb (200 kg) and an additional 4.4–13.2 lb (2–6 kg) of propane per process. In the LPC furnace, acetylene consumption is reduced to 39.2 lb (17.8 kg) because carburizing gas only flows during the boost phase.

Importantly, the LPC process does not generate direct CO₂ emissions, unlike an atmospheric furnace, which emits approximately 1325 lb (600 kg) of CO₂ per cycle. Cooling water consumption in the new LPC furnace is also reduced by over 45%.

The presented comparison of utility consumption in the two types of furnaces directly translates into the economic aspects of using these devices and conducting production processes. For cost comparison purposes, the following unit utility costs were assumed, as presented in Table F:

Table F. Unit costs of energy factors and technological gases according to European averages

In summary, the total utility costs for the process conducted in the Pit-LPC at 1800°F (980°C) are 53% lower compared to an atmospheric furnace conducted at 1700°F (925°C). At a temperature of 1925°F (1040°C), savings reach 60%. These savings are primarily due to lower energy and process gas consumption. Furthermore, the lack of CO₂ emissions eliminates the need to pay emission fees.

The efficiency of this furnace is almost twice as much at 1795°F (980°C) and three times as much at 1925°F (1040°C) compared to an atmospheric furnace.

Summary

The new Pit-LPC vacuum furnace combines the design features of a top-loaded pit and performs carburizing using vacuum technology instead of atmospheric technology. Bringing higher processing temperatures than traditional atmospheric furnaces to the market, as well as the ability to open hot in an air atmosphere, this technology proves that direct transfer of the charge to the hardening tank is possible in vacuum furnaces.

Another key development, this design significantly shortens carburizing time compared to atmosphere furnaces since the furnace can operate under vacuum, inert gas (nitrogen, argon), air, and carburizing gases, at temperatures up to 2010°F (1100°C).

Since this new pit furnace design does not require the use a retort or atmosphere mixer, which are the most vulnerable components inside a traditional atmospheric furnace, the furnace operates with greater reliability and lower costs. Furthermore, an efficient and robust vacuum pumping system provides the vacuum environment and operational readiness in less than 30 minutes. Time is also saved by the integrated closed-loop gas cooling system that shortens cooling time: dropping temperatures from 1800°F (980°C) to 1545°F (840°C) in 30 minutes for a full charge and to 210°F (100°C) in two hours for an empty furnace, operations which would take several hours and days respectively in atmosphere furnaces.

The advanced thermal insulation and a uniform heating element layout ensure high energy efficiency and precise temperature uniformity in the working space, yielding additional cost and energy savings.

This carburizing process is based on FineCarb LPC technology and supported by the SimVac simulator, enabling precise carbon profile shaping and achieving layers 0.148–0.154″ (3.77–3.91 mm) thick with high repeatability.

With the ability to operate at temperatures up to 1925°F (1050°C), the new LPC pit-styled furnace significantly shortens process time, reduces utility consumption, and lowers operating costs by up to 50%, while increasing productivity by a factor of x2 to x3. One of these furnaces can replace two to three atmosphere furnaces of the same size.

Finally, the furnace operates in a safe and non-flammable atmosphere, emits no direct CO₂, and reduces energy consumption, making it an environmentally friendly solution.

Conclusions

The Pit-LPC furnace is a modern alternative to the traditional atmosphere furnace and offers a number of advantages in terms of quality, efficiency, safety, economy, and ecology. Providing an innovative solution for vacuum carburizing and meeting stringent carburization layer thickness guidelines, this design is a viable option to fully replace traditional atmospheric pit furnaces operating in a carburizing atmosphere.

References

GlobeNewswire. 2024. “Wind Turbine Market to Reach $115.2 Billion Globally by 2033 at 6.2% CAGR: Allied Market Research.” GlobeNewswire, September 18, 2024. https://www.globenewswire.com/news-release/2024/09/18/2948365/0/en/Wind-Turbine-Market-to-Reach-115-2-Billion-Globally-by-2033-at-6-2-CAGR-Allied-Market-Research.html

GearSolutions. 2009. “Carburizing Wind-Turbine Gears.” Gear Solutions, May 1, 2009. https://gearsolutions.com/features/carburizing-wind-turbine-gears/

Jantara, Valter Luiz Jr. 2019. “Wind Turbine Gearboxes: Failures, Surface Treatments and Condition Monitoring.” In Non-Destructive Testing and Condition Monitoring Techniques for Renewable Energy Industrial Assets, edited by Mayorkinos Papaelias, Fausto Pedro García Márquez, and Alexander Karyotakis. Amsterdam: Elsevier.

Perumal, S., and G. P. Rajamani. 2014. “Improving the Hardness of a Wind Turbine Gear Surface by Nitriding Process.” Applied Mechanics and Materials 591: 19–22.

Rolinski, Edward. 2016. “Modern Nitriding Techniques for Gear Applications.” Gear Solutions, March 16, 2016. https://gearsolutions.com/departments/hot-seat-modern-nitriding-techniques-for-gear-applications/

About The Author:

Tom Hart
Director of Sales for North America
SECO/WARWICK Corporation

Tom Hart joined SECO/WARWICK in 2011 as a sales engineer and has been in the precision manufacturing industry for over 16 years. His responsibilities have him caring for SECO/WARWICK’s clients and their various process and heat treatment equipment needs. Tom received his manufacturing engineering degree from Edinboro University of Pennsylvania, has authored numerous white papers, and is recognized throughout the heat treatment industry as a go-to-guy for thermal processing.

For more information: Contact Tom at Tom.Hart@SecoWarwick.com.

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Heat Treat Radio #127: The Case for Modular Vacuum Heat Treating

November 20, 2025 / HARDENING TECHNICAL CONTENT, HEAT TREAT RADIO, MANUFACTURING HEAT TREAT TECH, QUENCHING TECHNICAL CONTENT, VACUUM FURNACES TECHNICAL CONTENT

In this episode of Heat Treat Radio, host Doug Glenn invites Dennis Beauchesne of ECM USA to explore the technology, benefits, scalability, and sustainability of modular heat treating systems. Together, they discuss how shared utilities, automated transfers, and adaptable heating cells can replace multiple standalone furnaces without compromising quality or precision. Learn how these systems streamline and simplify operations for future expansion — one cell at a time.

Below, you can watch the video, listen to the podcast by clicking on the audio play button, or read an edited transcript.

Heat Treat Today · Heat Treat Radio #127: The Case for Modular Vacuum Heat Treating

The following transcript has been edited for your reading enjoyment.

Introduction

Doug Glenn: I am very privileged to have with me today, Dennis Beauchesne from ECM USA. We’re going to be talking about modular heat treating systems, which is a growing category of equipment.

ECM Synergy Center (00:50)

Doug Glenn: Tell me about ECM’s Synergy Center, which is where you are at right now, on the shop floor.

The ECM Flex 600TG vacuum furnace located in the ECM Synergy Center Source: ECM USA

Dennis Beauchesne: I’m standing here in the middle of our Synergy Center. It’s about a 5,000-square-foot facility that is dedicated to proving out client parts for testing various processes, mostly LPC, but we also do a number of other processes here. We have a full metallurgical lab, 3D microscope, a number of tools, including a CMM that we can do before and after heat treat distortion testing for clients that want to know how much their parts move.

It’s a dedicated center just for clients to use. We also use the center for pre-completion of installations, final testing, and training, such as training on maintenance, understanding the software, and how everything works together.

Doug Glenn: It’s proof of process plus much more — helping clients’ proof of process.

Dennis Beauchesne: Absolutely. That’s a big part of convincing people that this process is for them and that it works on their part. We can send them ten different reports of an exact same material and part, but they want to know what their part will do.

What is Modular Heat Treating? (02:50)

Doug Glenn: On a very basic, rudimentary level, what is modular heat treating and how does it differ from what might be considered standard or normal heat treating?

Dennis Beauchesne: A modular heat treat system is one that works together to have more than one furnace working in the same platform. You may have a shop that has five or six vacuum furnaces separated — they each have their own door, vacuum system, electrical supply, quench motors…those types of components. Or you may have a series of batch IQ furnaces for carburizing; those systems are one off, which means they are individual, independent systems.

In a modular system, you try to utilize those facilities for the use of multiple heating chambers. Instead of having one vacuum furnace with one set of pumps and one gas quench motor, what we would do is have three to eight heating cells that would be utilizing one quench, depending on the process timing; that’s all done with an internal transfer car and we try to utilize one vacuum system. It’s much smaller than what you would have for three, four, or even eight cells.

If you had oil or high pressure gas quenching, which is what’s dominating right now in the modular heat treat business, you could supply basically six batch IQ hot zones to one oil quench.

The savings then are huge simply by removing five or six other quench tanks in front of this system, as well as leveraging the floor space (and the number of pits you have to dig). Other advantages including utility savings and utilizing equipment across a number of heating chambers.

Doug Glenn: This modular approach is basically separate chambers that are dedicated to doing whatever that chamber is doing, and they are all in some way interconnected. For standard units, you would heat up, pre-process, do the actual process itself, cool down, all in the same chamber. In a modular unit, you move from chamber to chamber to do each of those separate steps.

Dennis Beauchesne: Yes, I refer to it as a continuous batch.

Doug Glenn: Continuous batch. We were talking before we actually hit the record button with your colleague there, Allison DeAngelo, who just got done visiting the Heat Treat Boot Camp. We were talking about different types of furnaces, and we started talking about continuous vacuum, which of course, is almost a misnomer — a vacuum can’t be continuous because you have to open it up and break the vacuum to get stuff out. Anyhow, we talked about it basically being a batch, right? A batch furnace that’s continuous, a continuous batch furnace.

Benefits of Modular Heat Treating (06:35)

Now that we have a basic understanding of what these modular systems are, why would companies want to move from the standard type of heat treating system to a modular system?

Dennis Beauchesne: Manpower. If you are running five or six vacuum furnaces, you are going to need a number of people to open the doors, put new loads in, those kinds of tasks. With a modular system, you only have one entry or one exit area. Therefore, you are only going to load once every 15-20 minutes, and the system is going to take over and control that load going through the system.

In addition, especially in a carburizing atmosphere situation, you can have every load be a different case depth — a different process in each cell — and then the next load that goes in that same cell can be totally different from the one before. For instance, if you had a batch IQ, you typically use the same carbon potential, and you are typically going to run the next load almost identical to the one before. In contrast, with the modular system, each cell can run a different process every load.

It’s also easier to integrate automation if you are doing capacity increases.

Throughput Comparison (08:00)

Doug Glenn: What is the comparison of throughput between a standard unit and a modular unit?

Dennis Beauchesne: The throughput comparison is interesting because you typically can use a little higher temperature for a carburizing and a little higher carbon potential, and of course that’s what we specialize in here with the modular systems. You can achieve about a 30-40% gain in your cycle time. That furnace is operating very close to 100% occupancy, because when that load is done, you are moving it out right into the gas quench. Then, the next load comes and goes right into it.

Doug Glenn: You are able to increase your throughput because you have basically 100% utilization of the equipment or very close to that. Comparatively, you don’t necessarily have that in the standard equipment.

Product Quality Comparison (09:15)

Doug Glenn: Do modular systems produce higher quality products?

Dennis Beauchesne: The quality of the parts coming out of the system is improved. A vacuum environment is a very clean environment, especially if we are considering atmosphere and low pressure carburizing — it’s in a vacuum. We typically do everything in high pressure gas quenching. However, even in oil quenching under vacuum, you are going to have a much cleaner part.

Also in low pressure carburizing, the carburizing is much more uniform throughout the part because we heat it to temperature under nitrogen before the part gets to austenitizing temperature to start attracting carbon. We make sure that the full part, that’s the tooth, the root, every piece of the part, is at temperature before we start adding carbon to the load, which makes a more uniform case depth, and therefore makes a stronger part.

Doug Glenn: Since each module, each chamber, is dedicated to doing what it is supposed to do, it seems like the consistency and the reliability of the parts being processed in a modular system have a much better chance of being higher quality.

Dennis Beauchesne: You do not have six different variable chambers or six different variable systems. You just have to look at monitoring the connection between those and understanding that the vacuum levels are all the same across the levels and across the cells. Each cell can meet a different temperature and run a different process, but those are consistent across the board.

Typical Dedicated Cells/Chambers (11:10)

Doug Glenn: What would be the typical dedicated cells/chambers of a modular system?

Dennis Beauchesne: It is dependent on the processes. They are most widely used for vacuum carburizing. For pre-oxidation and preheating, we usually use an air oven outside of the system, and we connect that with an external loader. Before the load goes into the modular system, the load will go through a regular air oven, be heated to around 700°F (400°C), and then the load will be moved in.

For sintering and those kinds of applications, there is a debind step or a preheat step that would be done in one cell. Some of the processes that can be done in a modular system include:

Low pressure carburizing
Low pressure carbon nitriding (LPC)
FNC (ferritic nitrocarburizing)
Nitriding
Debinding
Sintering
Neutral hardening

The most prominent process right now is LPC, and that is being used all over the world in these systems.

Advantages of a Modular Unit for Captive Heat Treaters (12:53)

Doug Glenn: Why would a modular unit be beneficial for a captive heat treater, someone who does their own in-house heat treating, which probably means they’ve got potentially high volume, low variability as far as their workloads?

Dennis Beauchesne: The modular unit has many different advantages. First of all, floor space. You are going to save a lot of floor space by not having multiple furnaces set up separately. You will also save utilities because you would not have as many vacuum pumps or electrical systems running these furnaces on their own. You will have some shared service and utilities in that fashion.

Doug Glenn: That would also likely lead to maintenance cost savings as well, correct?

Dennis Beauchesne: Yes, it all goes down the line. Anything that you have multiples of, you are going to have much less costs than on a joint system. The modular system might be a little larger than one singular unit, but there will be fewer of them.

For vacuum carburizing applications in a captive shop, the quality and cleanliness of the part is very, very important. Gas quenching lends itself to no oil in your plant, no washers necessary for a post-quench. Typically, there’s a washer before the process starts, but you do not have to have any wash to get the oil off of the parts with a modular unit — you do not have to reclaim the oil or the water from the washer. You would not have waste oil in your plant either or any oil on your plant floor. These are some of the reasons some of the larger captive shops have gone to the modular systems.

Also, safety: There are no open flames with a modular unit, no risks of fire on the systems. They are also easier to maintain. For a fully operational, let’s say, eight-cell system for high production, captive operation, it would only take about five hours to cool that whole system down if you had to go in and work on the whole system. In comparison, it’s going to take you three to four days sometimes to cool down a typical atmosphere, high-temperature furnace.

It also takes time to heat the system up again. In a modular system, it takes about an hour and a half to heat the system up again and then you are ready to start running. That means now you can schedule your downtime on weekends or holidays. You do not have to have staff present to run anything.

You also do not have to have a secondary equipment, like Endo generators running to feed the carburizing gas. The carburizing gas is using acetylene out of cylinders, it’s not a regenerative system. You do not need a separate piece of equipment to feed to the furnace.

Another benefit is CapEx expansion. Typically, captive heat treaters do not want to buy everything upfront because their volumes are going to increase over time. In the beginning, they typically only need one or two cells ready to do a small amount of production so they can prove out the production and prove out the system. Then they can start building the system with more cells and more capacity later on. Generally, it’s two to three days of downtime to add a cell to a system. It’s very convenient to do that with a modular system. All of the utilities are typically alongside the modular system so that you can easily add those or add a cell to it over a short period of time, and those cells can be ordered a year or two down the road whenever you might need that.

You also can order peripheral equipment, like extra temper ovens or additional automation. You can add a robotics system to the layout as well. That’s why captive shops are very interested.

Finally, workforce: It’s a little bit easier to get someone to work on a modular system. These systems are completely clean and white. The one located in our Synergy Center has been there for eight years. We use it every single day, and it’s a very clean aesthetic environment for someone to work in. These systems are also water cooled, which means not a lot of extra heat in the building around you to work in.

Advantages of a Modular Unit for Commercial Heat Treaters (17:59)

Doug Glenn: What are some advantages of modular units for commercial heat treating?

Dennis Beauchesne: On the commercial heat treat side, modular units are typically useful because you can get multiple processes out of similar cells and you can have a system that has oil and a gas quench.

You can have a lot of flexibility in that one system that you have in the plant. I’ve visited hundreds of captive and commercial heat treaters. They generally have a number of furnaces in one area of the plant, and a number of furnaces in another area of the plant. A modular system gives you all the capability in one machine and one tool: oil quenching, gas quenching, FNC, nitriding low pressure, carburizing, carbonitriding, and neutral hardening all in one piece of equipment.

Automation and Robotics with Modular Heat Treating (18:57)

Doug Glenn: What automation and robotics advantages are there with modular systems?

Dennis Beauchesne: This is the new trend. People that have modular systems are now considering, “How do I automate the system to get more production out of it?” And what we’ve been doing the last five years especially is implementing systems that use CFC fixtures.

CFC fixtures are very robust in the furnace but sensitive to being controlled outside. Therefore, what we try to do is have the CFC fixtures be utilized in an automation that no humans have to interact with it. We usually use robots for external loaders and internal loaders to move the fixtures through the process.

This causes you to have a lighter load, which means less heating time, less energy being consumed. Also, the fixtures last three to four times longer if they’re not damaged. But of course, all of these systems can be using regular alloy steel as well, and we can fixture different parts. You can use baskets, we are now doing bulk loading where we have parts that are filled into baskets and then processed. We are doing that with vacuum carbonizing as well, not just neutral hardening.

So it’s really interesting to see how the limits are being pushed, as well as the different materials that we are gas quenching now. I know 20-25 years ago, we were quenching some simple materials that were very high hardenability, and today we’re quenching a lot of less hardenability steels.

Doug Glenn: Is that primarily due to increase of pressure in the quench?

Dennis Beauchesne: It’s pressure, it’s flow, it’s the intensity of the gas going through the parts. It’s also heat removal as well — heat exchangers, removing the heat out of the load faster. We also have reversing gas quench motors to reverse the flow inside from top to bottom, bottom to top, in the middle of the cycle.

Sustainability of Modular Heat Treating (22:24)

Doug Glenn: Do these systems promote sustainability and greenness?

Dennis Beauchesne: Absolutely, especially when it comes to carburizing. These systems have been compared against typical atmosphere carburizing cycles, and only about 4% of the carburizing time has gas injection, when we are actually injecting acetylene and having hydrocarbons being used in the process.

If you took the same cycle times, seven or eight hours of a carburizing cycle, you are flowing Endo gas or nitrogen methanol in the system for that full time. In contrast in a vacuum carburizing system, it’s 4-5% of the time of the cycle that you’re injecting into the furnace. Ultimately, you only have about 10% of the CO₂ output that you would have in a typical atmosphere furnace.

As mentioned previously, there’s also no oil in your plant. You’re not reclaiming oil out of the water and the wash or off the floor or in your car when you leave your heat treat shop.

How Does the Modular Heat Treating System Work? (23:40)

Doug Glenn: Let’s talk through the process a little bit. You provided us with figures to aid in describing the process. We have included these. Describe how the system works.

Dennis Beauchesne: This animation is a plan view of one of our Flex systems. In the center, going left to right, is a tunnel section. This tunnel section is about an 8-foot diameter. It has an automated loader that moves down left to right or horizontally, and it transfers loads from each cell to another, in and out.

On the bottom left is a loading/unloading chamber. In that loading/unloading chamber, we remove the air once the load is put in there, and then we balance the vacuum on that cell to the tunnel’s vacuum. Then we’re capable of moving that load to an available heating cell, and that would be on the right of the system — on the top right or the bottom right of the tunnel, those are heating cells. Then recipe for that particular load will be loaded into that cell. While that load is processing, another load will be moving into the tunnel and into the other heating cell as well.

On the top left is the gas quench cell, which could be in this orientation or instead have an exit on the back as well. In this system, you could do neutral hardening, carbon nitriding, LPC, a number of the processes. This is a very valuable tool, especially in a commercial heat treat heat treat shop.

Doug Glenn: Is this whole unit, including all four chambers under vacuum? I noted there are separation doors on the purge and the entry chamber. Can this area be vacuum sealed?

Dennis Beauchesne: Yes. There are vacuum seals on the loading/unloading chamber on the bottom left and then the top left. The gas quench also has a seal from a pressure standpoint. The two heating chambers have a graphite door — we call it the flap door, and it just flaps and it doesn’t really seal actually against another face of graphite. It’s graphite-to-graphite. We pull vacuum out of there through the tunnel to create the central vacuum pressure in the system. We also pull vacuum from the cell itself, and we could also have a separate door on the front of the unit if the process necessitates that or if we feel that a door is needed there by a client.

In a normal state or a standard unit, there are no hot seals on the door, only vacuum seals on the loading/unloading chamber and the gas quench.

Doug Glenn: In the animation, your vacuum pumps are down in the bottom right, correct?

Dennis Beauchesne: Exactly, that’s a process pump.

Doug Glenn: What is located in the top left?

Dennis Beauchesne: On the top left, we have a gas quench tank. We want to ensure we have enough gas pressure and volume there to quench the load quickly. It’s very important to get the gas through the gas quench quickly.

ECM Flex 600TG vacuum furnace with two added heating cells / Source: ECM USA

Now, we have added two more additional heating cells and a central tunnel section. In essence, you just doubled the space, doubled the capacity of the unit, where you only added 50% of the space of what you had for capacity before.

We are still utilizing the same gas quench and the same loading/unloading cell. We only added utilities for the two heating cells, not for a whole gas quench or oil quench capability there; this can be added in a very short time.

Doug Glenn: Now I’m gonna go let this video roll here for a minute. There we go.

**ECM Flex 600TG vacuum furnace with four added heating cells for six heating cells total**

Dennis Beauchesne: So now we added another 50% capacity with two more heating cells (six heating cells total) and a tunnel section. Typically, what you want to do is to have the tunnel sized for about five years out for your capacity and then buy the cells as you need them and have it grow so then the tunnel is ready to implement.

We have just tripled the capacity of this installation, and we are only still using the same gas quench and the same loading/unloading cell. Generally, this system could go to eight cells and have just one gas quench, that’s our typical orientation.

Doug Glenn: It looks like we also added a discharge side here. Whereas before we were going in and out.

Dennis Beauchesne: Yes, this adds to the efficiency of the system because the load is already in the gas quench when it’s finishing, so it just exits out the back, out the door.

Doug Glenn: Now what do we have here?

**ECM Flex 600TG vacuum furnace processing different treatments in each cell. See animation above to watch the animation in motion.**

Dennis Beauchesne: We have the loads entering, and the loads will go to the first cell that is available (empty). Then that recipe would be downloaded for that cell, and then the next load will go to the next available heating cell and download that recipe into that cell. These could be two different loads.

One load could be for neutral hardening; one could be for carburizing. One could be for carburizing in a low case depth. The other one could be carburizing at a deeper case. In this case, we just see the gas quench on here, but this tunnel could also be outfitted with an oil quench as well, and you could have one load go into gas, quench one load, go into oil quench or both going to either.

Doug Glenn: This gives people a sense of what the process looks like.

Processes and Materials for the Modular System (30:29)

Doug Glenn: Are there any processes or materials that do not make sense to process them through one of these systems?

Dennis Beauchesne: If you are doing a lot of annealing and normalizing, those are longer cycles. There is some regulated cooling that occurs. This is not really the type of equipment investment that you would want to make for those processes. If you were going to use it for a few loads in your plant where you received parts that weren’t annealed or you wanted to try to anneal a part for a particular process before you went to full production, you could certainly use a modular system for that, but it’s not a cost effective methodology. Neither would we recommend preheating in the cell. However, it is very flexible for a number of other processes that we have mentioned.

The size of the part is also important to note. These systems are typically 24 inches wide and about 39 inches long and about 28 inches high. However, we will soon have a new system, the Flex Max, a 12-9-9 system. It’s a 36×48 unit that comes with an oil quench and is modular, like this. We can either do an oil quench or a slow cool cell on that system. So, we will have that capability of 36×48 in that modular system.

Other than that, restrictions on material? Very few there. Like I said, you would not want to do annealing and normalizing on a lot of parts, but you could do it in these units.

Doug Glenn: It sounds like the sweet spot is surface modification type applications, and some sintering is possible with dedicated chambers.

Dennis Beauchesne: Yes, sintering and brazing is also possible.

Doug Glenn: Does that include aluminum brazing?

Dennis Beauchesne: Not aluminum brazing, but some brazing applications.

Expenses with Modular Heat Treating Systems (33:03)

Doug Glenn: What would be considered capital expenses for this modular system?

Dennis Beauchesne: As far as capital expenses, it’s not a furnace-to-furnace comparison. Clients always ask how much our furnace is. But companies need to first take two steps back and take a look at their incoming material, how they would like to be able to modify that incoming material in their heat treat process to make sure that their outgoing quality is higher than it is today. That’s the kind of benefit that this type of modular system gives you — a better quality part, safety in your plant, and a better quality work environment with being able to turn the system off and not need additional personnel around.

These are all factors that have to be considered when thinking about the CapEx expenditure and investment. When we consider these factors, a modular system investment is a much better situation than looking at a furnace-to-furnace replacement, and that’s really the thought process that clients need to go through to understand the actual investment and value of the system.

Doug Glenn: What about the operational expenses?

Dennis Beauchesne: For instances, if you had a batch IQ sitting there, you would typically keep it running whether it has a load in it or not. With a modular system, you just shut off that cell that you’re not using. It does not take any more energy. If you are not working five days a week, you do not use it on the weekends — you shut it off. You do not use it during Christmas shutdown or any holiday shutdown, vacation shutdown. You’re able to shut it off and that means saving a lot of energy and labor by having it off.

Also, in the opposite way, you could run it lights out if you wanted, as well. You could stock up a number of loads on the automation before you leave, have the system operate it, run it, and have the load come back out before the morning. You could have it time start as well, if you wanted to start it on Monday at 5 AM, but you will not be there till 8 AM. You would come in and the furnace would be hot and ready to run a process.

There are a number of operational advances over the typical operational heat treat that’s out there today.

Doug Glenn: How does maintenance work with these systems? Say your heating element goes bad in cell number three, do I have to shut the whole system down to fix or can I fix number three and leave the rest of the system up and running?

Dennis Beauchesne: In this situation if you had a tunnel like we showed, you would typically shut off that cell; that is, if you knew that heating element was out or it wasn’t heating properly, you could shut off that cell, de-validate is what we call it, and then keep running the rest of the system until you had a window in your production that you could shut the whole system to get into that heating element.

If you had a system with doors on the front, it could be possible to go in the back while the system is operating. Then, it would be all based on your safety requirements for your plant and those kinds of things.

To do that, we have another system called the Jumbo, and it is much more flexible in the maintenance world. It has a vacuum car that moves down on rails and docks and mates with every heating cell on the system. In that line, the heating cell can actually be isolated from the rest of the line. You would just slide it back (It’s on wheels, it slides back about three feet away from the line), you put in a new piece of safety fence, and you continue to run your line. You can completely lock out/tag out that cell and work on it completely.

Doug Glenn: How would you approach a vacuum leak since the whole system is connected, right? I believe you mentioned these are graphite-on-graphite doors.

Dennis Beauchesne: You would want to fix the leak before you move on. Especially if it’s a bad leak. If it’s something that’s causing you to not maintain your process pressure, you certainly don’t want to do that, and that’s true with every vacuum piece of equipment.

ECM Modular Systems (38:55)

Doug Glenn: How many of these modular type systems does ECM have out in the marketplace?

Dennis Beauchesne: The Flex is the most popular modular system, which we discussed with the animation. We also have a number of Jumbos systems, and the unit in our Synergy Center is called a Nano, which has become more and more popular these days. The Nano has three different size chambers, but they’re typically smaller, 20x24x10 inch high size chamber. I explained a little bit about the Flex and the Jumbo is the same.

Out of those three systems, we have more than 350 modular systems, not just the heating cells, but more than 350 systems that are out in the marketplace today operating, running parts every day, running millions and millions of parts every week. Those systems are comprised of about 2,000 heating cells. As much as people hear about this being a new technology, it has actually been around about 30 years, and many companies have been using these systems and have replaced a number of pusher furnaces and those style furnaces for high-capacity installations especially.

Doug Glenn: Okay, that sounds good. I really appreciate your time.

About the Guest

Dennis Beauchesne
General Manager
ECM USA

Dennis Beauchesne joined ECM over 25 years ago and has since amassed extensive vacuum furnace technology experience with over 200 vacuum carburizing cells installed on high pressure gas quenching and oil quenching installations. Within the last 10 years, his expertise has expanded to include robotics and advanced automation with the heat treat industry high-demand for complete furnace system solutions. As General Manager of ECM USA, Dennis oversees customer supply, operations and metallurgical support for Canada, U.S., and Mexico for ECM Technologies. He has worked in the thermal transfer equipment supply industry for over 30 years.

For more information: Contact Dennis at DennisBeauchesne@ECM-USA.com.

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Heat Treat Radio #127: The Case for Modular Vacuum Heat Treating Read More »

5 Things To Consider When Choosing a Refractory Lining

November 17, 2025 / Manufacturing Heat Treat Technical Content, VACUUM FURNACES TECHNICAL CONTENT

For heat treaters, choosing the right refractory lining is critical to keeping furnaces running safely and efficiently. Linings must endure extreme heat, stress, and chemical attack while balancing downtime, longevity, and cost. In this article, Plibrico Company Technical Services Group explains how refractory engineers carefully balance five critical factors to deliver solutions that meet today’s demanding production needs.

In refractory lining maintenance, recommendations for repairs and relines often consist of selecting a similar or equivalent material to replace the original. Sometimes that’s sufficient. Many refractory contractors and maintenance teams strive to use best practices by purchasing the same refractories that have worked on similar equipment in the past, but this carries the risk of assuming that nothing has changed in the process, production, or maintenance of the equipment over time. This assumption can be a dangerous bet because furnace equipment is made to meet the immediate demands of each thermal processor, and these demands often change depending on factors like production orders and maintenance capacities.

Choosing an appropriate refractory lining for an application isn’t always a straightforward decision. Many times, it is part science and part art. Making an effective choice requires knowledge of the industrial application process, refractory performance expectations, and potential refractory service failures. These factors must then be weighed against each other to find the right balance and best solution.

While there are a number of important criteria to consider, refractory engineers focus on five aspects to evaluate and choose a refractory material for each specific application: thermal, mechanical, chemical, logistics, and value — as well as connections among these aspects.

What is the best refractory material choice? To answer this question, each individual application requires an overall evaluation of the thermal processing furnace in relation to each of the five factors, and then a careful balance of each of these in finding the best solution that meets both the immediate and long-term needs of the thermal process.

Thermal Requirements: Temperature

For any high-temperature industrial process, the primary piece of information is the operating and maximum temperatures. The refractory lining chosen must meet the operating temperature requirements.

Refractory linings are designed to maintain physical properties at very high temperatures — 932°F and above. Refractories used to line thermal equipment must have proper insulating properties to reduce the steel skin temperatures to acceptable levels, usually well below 300°F. Multi-component linings employ a dense refractory material at the hot face with an insulating refractory or ceramic-fiber board or blanket behind it, well-known for achieving adequate cold-face temperatures with structural integrity for long thermal life.

Spalling and thermal shock are the most common thermal failure mechanisms in a refractory lining. These are due to crack formations caused by temperature cycling and high thermal loads. There’s more to learn about fracture mechanics thanks to expert research, but knowing the importance of this phenomenon is enough for the application specialist.

Refractory engineers working on refractory layer
Source: Plibrico

In recent years, many thermal processors have experienced increased production demands. Meeting that need means that their furnaces are operating at higher temperatures for increased output. Running furnaces harder and faster often has the unintended consequence of overheating the refractory to the point that phase changes in the refractory matrix start to occur, causing lower-temperature glassy phases to form, softening the refractory, and shortening life. Due to this, the refractory engineer often needs to consider a material with higher refractoriness to meet the performance needs of shock resistance and high thermal loading. This usually means a higher-alumina material.

Physical Properties: Mechanical

The vast majority of higher-performing refractories in service today have been developed to maximize a material’s physical properties to improve lining lifespan and keep furnaces running at their best performance. Much of the information on a product Technical Data Sheet is devoted to the physical properties of the material, such as cold crushing strength, hot/cold MOR, and abrasion resistance. All of these are based on well-defined ASTM standards to make valid comparisons among available choices.

Refractory linings experience all sorts of mechanical and thermal loads that lead to wear and eventual failure, requiring repair or replacement. Some of these include excessive expansion, thermal cycling fatigue, mechanical impact (dynamic loading), severe abrasion and erosion, pinch spalling, tensile loads, large hydraulic loads (such as in molten-metal containment furnaces), and creep (deformation at high temperatures over time). While a deeper discussion of each of these failure modes is beyond the scope of this article, knowing the type of potential refractory failures for each application becomes the solution in choosing the refractory to best address the failure mode present.

During a visual refractory inspection, the lining can often give clues about failures. Crack patterns, wall buckles, surface spalls, discolorations, and other visual differences occur in locations and manners that correspond with their failure type. Mechanical and thermal forces will find weak points and initiate cracking. Many times, these occur in typical geometric locations and patterns, such as sharp inside corners, archways, midpoints of a lining, and in circular patterns, indicating a particular failure system. These will usually indicate shock and expansion due to high thermal loads, inadequate expansion allowance, deficient material properties for the application, and/or improper anchoring.

Corrosion: Chemical

Chemical attacks on the refractory matrix have been a fundamental concern of ceramics engineers since the beginning of refractory development. Chemical reactions between the vessel’s contents and the refractory at high temperatures can cause a change in the structure of the refractory matrix, which can have a detrimental effect on the performance and life of the lining. Chemical or mineralogical changes due to reactions occurring within the refractory lining can cause excessive volume change of the crystal structure or reduction of the oxides in the lining, leading to a breakdown of the ceramic bonds in the cement. The most common examples of these are:

A reducing atmosphere of carbon monoxide reacting with the lining, such as in CO boilers

An H₂ reaction in the lining, which reduces silica in the refractory matrix at high temperatures

Molten slags, such as in coal-fired boilers

Alkali corrosion from ash in wood-burning furnace applications

Corundum growth in aluminum furnaces, especially those with aggressive alloys containing MgO

Installation: Logistics

In addition to the aforementioned elements, refractory construction contractors are faced with multiple logistical pressures to get their clients’ thermal processing equipment back on-line. This means that the choice of anchoring systems, installation methods, and bake-out becomes an important consideration.

The adage “time is money” is often a deciding influence when crafting a refractory solution. “Get it back up and running ASAP” is often the most pressing need communicated by the thermal processor. For example, while a brick lining often gives clients a highly durable option, bricking a job is very labor-intensive, requires high levels of experience, and usually takes a long time to complete. A cast-in-place lining may yield the best physical properties in service, but the time also needed for forming (or multiple formings), casting/pumping, then stripping may not be desirable. In other words, the required length of downtime may not justify these options.

Another example is the use of low-cement castables, which have superior properties. These have been around since the Plibrico Company first developed them, but they require more careful and longer bake-out. Gunning or shotcreting the lining could be a viable option if time or cost is a determining factor because forming is not required, and material can be placed at higher rates.

While a cast product theoretically produces the best physical properties in general, followed by shotcrete and gun mixes, time limits may require another method of installation. Other factors to consider may be to ram the lining using plastic, which requires no setting or moist cure requirements. With the advent of reduced bake-out refractories, such as Plibrico’s Fast Track castables and gun mixes, contractors can place material and fire several hours sooner. This saves time and money but often at a cost of reduced physical properties. Again, it is a balancing act.

Price: Value

Refractory linings are one of the most significant operational costs over the life of an industrial furnace. Therefore, when choosing a material for the application, price is always a very important factor. However, value is not only reducible to price; there is often more than one choice of materials to pick from.

The economics of each individual application can direct the engineer/specialist to recommend one solution over another. When we speak of price, the real driver is value. Everyone wants a refractory product installed that is good, fast, and inexpensive. However, it is often very difficult to achieve all three of these simultaneously. Value is the determination of the relative importance of each.

Conclusion

The question to be asked is this: What do refractory linings do? Their most basic function is to withstand very high temperatures; contain heat within a vessel; have adequate physical properties, such as strength; and resist chemical degradation or disintegration by aggressive atmospheres and corrosion by liquid slags and solids.

Choosing the right material solution for thermal processing applications requires balancing multiple aspects to determine a hierarchy of which aspect is most important. In many cases, there is no single answer to the problem. However, understanding the process, challenges, history, and root causes of refractory failures becomes the key to making the best decision to solve the problem.

For more information: For more information about choosing the best refractory lining, contact Plibrico Company at contact@plibrico.com or 312-337-9000

This informative piece was initially published in Industrial Heating. All content here presented is original from the author.

5 Things To Consider When Choosing a Refractory Lining Read More »

Customize To Build Better Furnaces

November 11, 2025 / AEROSPACE HEAT TREAT TECHNICAL CONTENT, AUTOMOTIVE HEAT TREAT TECHNICAL CONTENT, VACUUM FURNACES TECHNICAL CONTENT

Custom furnace design isn’t just about performance upgrades — it’s about process reliability. Vacuum furnaces built for general use, however, often fall short in high-precision industries. This Technical Tuesday installment comes to us from Scott Herzing, vice president of Engineering at Paulo. Explore how purposeful furnace design, smarter controls, and targeted customization can transform vacuum heat treatment.

This informative piece was first released in Heat Treat Today’s November 2025 Annual Vacuum Heat Treating print edition.

The reliability and consistency of vacuum heat treatment processes depend heavily on furnace design and performance. Standard furnace configurations typically serve general heat treating applications adequately. However, for industries with extremely demanding requirements, such as aerospace, automotive, and power generation, small variations in furnace design can lead to substantial impacts on part quality, increasing risks and costs. Achieving exceptional process control and repeatability often requires custom furnace modifications tailored specifically to the unique requirements of each process.

Extensive customization of vacuum furnaces can initially seem costly and complex. It takes experience operating and refining vacuum furnaces to know which adjustments deliver the greatest impact. This article taps into the more than fifty years of heat treating wisdom from Paulo with six key factors that drive better furnace performance, enhance reliability, reduce downtime, and create measurable efficiency gains.

Why Customization Matters

Conventional vacuum furnace models offered by manufacturers are generally designed to meet broad market demands. This often results in equipment that effectively balances functionality, affordability, and ease of use for a wide range of applications. However, certain high-precision thermal processing applications, especially those involving aerospace components like single-crystal turbine blades demand much stricter temperature uniformity, controlled quenching rates, and near-perfect repeatability from cycle to cycle.

In these cases, standard configurations can introduce variability that compromises quality. A better path is a case-by-case approach, evaluating specific process risks and targets critical components for modification. Precision upgrades can be integrated where they have the greatest impact, achieving the required level of process control. This makes it possible to achieve near-zero scrap rates, dramatically boost reliability, and achieve repeatability that far exceeds industry norms.

Advanced Pressure and Cooling Control

Repeatable quench dynamics is a game-changer when it comes to part quality. Integrating advanced gas control capabilities that extend beyond basic pressure management can help you improve heat treating results. To do this, you need to precisely control the rate at which gas is introduced into the vessel using proportioning valves, not just the pressure setpoint. For controlled cooling cycles, systems also need to manage the fan start speed, allowing you to tailor the convective heat transfer to the geometry and mass of each part. This level of precision ensures consistent metallurgical results and protects part integrity.

Automation-Ready Resilience

In multi-furnace environments that rely on automation and minimal staffing, power-failure restart behavior cannot be left to chance. Adding dedicated PLC logic for restart allows the system to record the exact state at interruption, verify safe conditions on recovery (atmosphere, temperature, motion, interlocks), and automatically sequence a safe restart when criteria are met. This reduces scrap risk, protects equipment, and stabilizes throughput, especially when only a few operators are covering many furnaces.

Hot Zone Design and Material Selection

A major component directly influencing furnace reliability and overall performance is the hot zone. As the central area where thermal processing occurs, the hot zone repeatedly experiences extreme temperature fluctuations, making its design crucial to operational efficiency and product quality.

Standard vacuum furnaces use thinner insulation layers and lower-cost materials to control initial investment costs. However, advanced hot zones can dramatically outperform these standards by incorporating thicker insulation layers, strategically placed air gaps, and specialized insulation materials, such as high-quality molybdenum, graphite felt, or carbon-fiber-carbon (CFC) boards.

These advanced materials not only prolong hot zone life but also substantially reduce heat loss, minimizing energy consumption and improving thermal uniformity. The enhanced durability also results in fewer service interruptions, less downtime, and lower long-term maintenance costs, ultimately justifying the higher initial investment. At Paulo, this is how we’re able to reliably run around 29,000 cycles per year in over thirty furnaces at our Cleveland facility.

Additionally, the hot zone’s construction details, including how insulation and heating elements are attached, can significantly affect longevity and reliability. Standard fasteners or attachment mechanisms may perform well in general applications but frequently deteriorate under high-stress thermal cycling. High-performance fasteners specifically engineered for high-temperature stability reduce the risk of premature failure and minimize downtime.

Enhanced Sensor Integration

Furnace reliability and consistency rely heavily on the accuracy, quantity, and strategic placement of sensors within the furnace chamber. Manufacturers’ vacuum furnace designs typically include a limited number of sensors monitoring basic parameters, such as temperature, pressure, and vacuum levels. Increasing the number and distribution of sensors throughout the furnace interior allows for a more detailed and accurate understanding of conditions during processing. By placing multiple sensors at critical points within the hot zone and throughout key furnace components, operators can detect subtle differences in temperature distribution, heat flow, gas pressures, and quench rates that might otherwise go unnoticed. This enhanced sensor density provides the detailed data necessary for real-time process adjustments, early detection of equipment issues, and predictive maintenance interventions, significantly improving process reliability and part consistency.

In addition, the rich data captured by a denser sensor network improves traceability and enables rapid identification of root causes when process deviations occur, ultimately reducing the risk of quality issues and equipment downtime.

Centralizing Your Control System

One often-overlooked factor in achieving highly consistent heat treating results is the adaptability and responsiveness of furnace control systems. Modern furnace control architectures benefit from a centralized SCADA layer with deep PLC integration. By recording every PLC input (thermocouples, switches, interlocks, drives, flows, pressures), the system enables technicians to diagnose issues without walking out to the furnace and manually testing components. With complete signal histories available, furnace issues can often be diagnosed and resolved remotely in minutes, improving first-pass resolution and minimizing production disruption.

Integrated control software should do more than log data; it should actively protect quality:

Automated compliance control: Continuously track process parameters, alarm on deviations, and initiate quality quarantines when limits are exceeded to prevent suspect parts from re-entering the supply chain.
Element-health monitoring: Monitor heating-element resistance to detect early signs of a heating system issue. If an anomaly is detected, automatically stop the heating process to protect parts and prevent secondary furnace damage.

These safeguards shift intervention upstream and reduce reliance on manual inspection alone.

Extending Auxiliary Equipment Life with VFDs

Variable-frequency drives (VFDs) on pumping systems can substantially extend motor and bearing life by matching speed to process demand and reducing mechanical stress. When control logic conditions are met, slowing pumps lowers load, heat, and vibration, which are key contributors to premature failures.

Without VFDs: Bearings on 615 blowers typically require replacement every 1–2 years, and motor failures occur more frequently than acceptable.
With VFDs + logic-based speed reduction: Bearing-change intervals extend to 10–20 years, with no motor problems, reflecting a step-change in reliability and lifecycle cost.

This targeted upgrade is a practical, high-ROI improvement that also helps decrease unplanned downtime.

Practical Realities and Final Considerations

Extensive furnace customization offers clear advantages, but it is not always practical for every operation or budget. In many cases, targeted, incremental upgrades — such as refining hot-zone insulation and attachment methods, adding or repositioning select sensors, or phasing in improved control software and deeper data storage/analysis — deliver measurable gains in reliability and process quality without large upfront costs.

Another practical path is to partner with a commercial heat treater that has already engineered and validated these enhancements at an industrial scale. This option can accelerate access to higher levels of precision and repeatability without requiring capital investment, engineering bandwidth, and learning curve of doing it all in-house.

Ultimately, achieving reliable and repeatable heat treatment results involves careful consideration of furnace design and functionality, aligned closely with your process requirements and economic realities. While extensively customized furnaces represent the ideal for particularly demanding applications, understanding the targeted areas where smaller customizations can yield significant improvements empowers heat treaters across the industry.

About The Author:

Scott Herzing
Vice President of Engineering
Paulo

Scott Herzing is vice president of Engineering at Paulo. He leads the company’s metallurgical, project and automation engineering, fabrication, and lean technology groups. With over 27 years at Paulo, Scott applies his passion for leadership, engineering, and problem-solving to help customers achieve advanced heat treating outcomes.

For more information: Contact Scott Herzing at sherzing@paulo.com.

Customize To Build Better Furnaces Read More »

Heat Treat Radio #123: Helium Leak Detection Tips for Vacuum Furnace Operators

July 24, 2025 / HEAT TREAT RADIO, Manufacturing Heat Treat Technical Content, VACUUM FURNACES TECHNICAL CONTENT, VACUUM PUMPS GAUGES VALVES NEWS

Helium leak detection is critical to ensure system integrity, product quality, and operational efficiency in vacuum processing. With 36 years of hands-on experience, Dave Deiwert of Tracer Gas Technologies joins host Doug Glenn on the most recent episode of Heat Treat Radio to share a wealth of knowledge on the evolution of leak detection technology, practical maintenance, and best practices for leak testing.

Listeners will gain practical insights into the best leak detection practices and how to troubleshoot challenges.

Below, you can watch the video, listen to the podcast by clicking on the audio play button, or read an edited transcript.

HTT · Heat Treat Radio #123: Helium Leak Detection Tips for Vacuum Furnace Operators

The following transcript has been edited for your reading enjoyment.

Introduction

Doug Glenn: Helium leak detection has come a long way, but not everyone has a brand new piece of equipment. So let’s talk about some of the shortcomings of older equipment and some of the improvements that you’re seeing.

Dave Deiwert: When I started in 1989, leak detectors pretty much had what were called oil diffusion pumps as the high vacuum pump. That’s the pump that creates the vacuum for the analyzer cell or mass spectrometer so they can separate helium from other gases. These diffusion leak detectors did not like to be shut down improperly or have power outages quite frequently.

You would hear stories of somebody that turned the power off of a leak detector without a proper shutdown or a power outage, and that could cause an oily mess from the diffusion pump, and maybe even crack the oil. So, you would end up having quite a maintenance event required on the leak detector before you could use it again.

In fact, these kinds of problems happened so frequently that in my young sales days when turbopump leak detectors first were introduced, as I would go in to show it to a potential client, one of the first questions was, “What happens if you have a power outage?”

I would have a little fun with that.

I’d say, “Well, let’s find out.” And I would pull the plug out of the wall, and they would say, “Oh, you can do that?” And of course you could. A turbo pump would just coast down towards a stop. Then we turn the power back on, and it’s back up.

Part of what compounded this problem with the diffusion pump is that it works by heating oil to jet mist oil vapor that goes to the top, and it’s condensed and directed back down. When power is lost, whether you turn the power off with an improper shutdown or a power outage, that pump is still hot for quite a while. It’s still trying to pump, and the backing pump, whether it’s a diffusion pump or a turbopump, is typically a rotary vane pump. With a power outage or power stop, those pumps will come to a stop very quickly. But those diffusion pumps and turbo pumps are not designed to exhaust atmosphere, so the backing pump or rotary pump comes to a stop pretty quickly, and now you have atmosphere potential on the exhaust of the diffusion pump.

The turbopump survives that much more nicely than a diffusion pump does. So the first major upgrade in the technology across the board with all the manufacturers was moving away from diffusion pumps to turbo pumps. If you buy a new leak detector from the ‘90s to today, it will very likely have a turbo pump no matter whom you buy it from and even if you buy a used one.

Size and Portability of Leak Detectors (00:06:09) 

Doug Glenn: How large were these original pieces of equipment? Did you have to wheel them around?

Dave Deiwert: The very first ones I worked with predominantly would be the size of a washer/dryer. They would typically have casters on so you can roll them around.

Turbopump Leak Detector
Source: LDS Vacuum Shopper

They took up more space and certainly took up a lot more energy. You could sometimes find what they would call portable leak detectors, but they would still have diffusion pumps in them, and they’d have less features because of how small they were versus the console leak detectors.

Doug Glenn: So now nowadays they use helium leak detectors.

Dave Deiwert: Most everybody’s gotten away from console leak detectors. You can find a couple companies that have a fairly large rolls-on-caster leak detector that still has turbo pumps, and higher performing backing/ruffing pumps. But the majority of leak detectors you’re going to find are more portable and smaller in size.

Doug Glenn: Are they close in size to a briefcase?

Dave Deiwert: They average 12 to 18 inches wide by 10 to 12 inches deep and 12 to 14 inches tall, approximately. So, much smaller than a washer/dryer.

Quite frequently, these leak detectors may be sold with a cart so that you don’t have to carry them from point A to point B. It can be a little laborious to still carry them. They weigh 40 lbs or more. So quite often, the first accessory purchased with the leak detector is a cart to roll it around.

Doug Glenn: So it’s a heavy piece of carry-on luggage essentially.

Dave Deiwert: Absolutely.

Maintenance: Old vs. New Leak Detectors (00:06:37) 

Doug Glenn: How would you compare the maintenance of those older units, assuming that you don’t lose power, versus maintenance of the newer units.

Dave Deiwert: A stereotypical experience from my field service days would be if you’re running a diffusion pump leak detector in a production environment, using it every day, then most likely you’re going to do what I call an overhaul of the leak detector. During this overhaul, you’re going to change your oils, change the filaments in the mass spectrometer, put on new valve seats, and clean the manifold.

Not everybody will do this. There are those that might go a year or two, especially if the leak detector is purely for troubleshooting, like if you have only a few furnaces. The leak detector may sit against the wall, and then you go get out to leak test a furnace. They may well get a couple of years of use out of a leak detector before needing to do any preventative maintenance or even a major overhaul.

With the new turbopump leak detectors, I think all the manufacturers now have models that most likely you’ll go multiple years without really doing anything other than changing oil in the backing pump, which you might do a couple times a year or so, keep an eye on the oil level, much more maintenance friendly and easier to do the troubleshooting and the service to it.

Filament Technology Improvements (00:08:10) 

Dave Deiwert: The next major upgrade in the leak detectors across the industry was the filament design.

The old diffusion pump leak detectors predominantly had tungsten filaments, which, if you’ve ever cracked or seen a cracked light bulb that had a tungsten element in it, you know that immediately you lose the function of the light bulb. And the same thing with the filaments that are tungsten in a mass spectrometer. If it gets a pressure burst, which is what I call the event when somebody disconnects the test port from the vacuum furnace while the leak detector is still in test, that allows a pressure burst into the leak detector and tungsten filament, and most likely you will burn out the filament. As a result, you will have a maintenance event for that.

As a rule of thumb, you will get 1,000 to 2,000 hours out of an old leak detector with tungsten filaments, but you’re going to get many thousands of hours out of a Yttria coated-iridium, which I think is used across the board in the industry today. In the case of

several years even, it greatly reduces your cost of ownership with the newer leak detectors.

Performance and Cost Comparison (00:09:12) 

Doug Glenn: Are there any other major differences between the old units and the new units?

Dave Deiwert: There are some extra benefits from the upgrades that we’ve talked about. The turbopumps will allow, at least modern leak detectors, us to test at a higher pressure (or less vacuum). You press “Start Leak Detector.” The test port pressure pumps down to some vacuum level. For diffusion pump leak detectors, they had to get down to typically less than 50 mTorr. Depending on the model, definitely significantly lower vacuum than the turbopump leak detectors. So, the turbopump ones with the gross leak testing capabilities, you’re probably looking at 18 to 20 torr. I think a couple of manufacturers claim they can get in the test pretty much right below atmosphere and start looking for very massive leaks.

The capabilities going to turbopump and Yttria-coated filaments has allowed manufacturers to greatly improve the performance and the robustness and reliability of the leak detectors.

Doug Glenn: In terms of cost comparison, are newer units more or less expensive than older units?

Weighing the costs and comparisons of different units

Dave Deiwert: When buying a leak detector in 1889 to early ‘90s, you’re probably looking at the low to mid-20s in price. You’re going to find they are a little higher than that now. With the market and inflation, you’re probably looking at upper 20s to low 30s for the most typical leak detectors that are purchased for the vacuum furnace industry. You can find some that are maybe two or three times that amount, but those are not needed for the industries that we’re talking about today.

Troubleshooting and Service Efficiency (00:11:00) 

Dave Deiwert: If the client, their suppliers, or people who work on the leak detectors from time to time service a diffusion pump leak detector, they may want to explore an idea to troubleshoot a problem. They may not be sure what the problem is yet.

First, you’re going to do a proper shutdown of the diffusion pump leak detector to protect the oil in the diffusion pump and the cleanliness of the leak detector. You may wait a good part of an hour for that diffusion pump to cool off before you can try the troubleshooting solution you’re going to investigate. Then you’re going to wait for another good hour for it to heat back up and be ready to confirm if what you have tried to do was successful.

With a turbopump leak detector, you turn a switch off to turn the power off, and within minutes you can test out the solution on the leak detector. So you greatly expedite your troubleshooting time.

What might have been almost always a full day event of troubleshooting and servicing a diffusion leak detector turns into less than a half day, possibly even an hour or two.

In every category, the newer leak detectors are very attractive. If clients or our viewers reach out to their suppliers or potential suppliers, there will most likely be some trade-in value for your old leak detector, which will also help offset the pain and suffering of spending money on a new leak detector.

Doug Glenn: Hopefully they’ll come pick it up, too.

Where to Connect Leak Detectors on Furnaces (00:14:11) 

Doug Glenn: In your column, you talk about how there’s some debate amongst users on where to hook up the leak detector on the furnace. Can you walk us through that a bit?

Dave Deiwert: I run into people who are very adamant that you hook up the leak detector in one of three places. And I’ve told salespeople that while we have our preferred location of where to hook to the leak detector, we should never visit a client and tell them they are doing it all wrong. As a field service engineer, I’ve confirmed that you can connect the leak detector at three most prominent locations, but the question is where is the most optimum place to connect it?

The first place is hooking the leak detector directly up to the furnace chamber, because that’s where they imagine the leaks might be. The next two locations might look like close cousins because they’re both in the series flow away from the chamber, through the pumps and out to the exhaust.

My preferred location is to connect it between the blower and the chamber. Or, if there’s

a diffusion pump, I would connect it between the blower and the diffusion pump.

The last place that you might see somebody connect it is between the blower and the backing pump or a roughing pump. They might do this to use the blower almost like a turbocharger to improve the signal to the leak detector. The disadvantage of doing that is most likely these vacuum pumps are very dirty single-stage roughing pumps. There are two concerns I have with this. One is the back stream of oil or hydrocarbons from that pump to the leak detector. And the second is the potential for back streaming, even of helium from the ballast port of the pump or the exhaust, depending on where the exhaust is terminated. If somebody exhausts the pump directly out of the building, then that’s not so much a concern. But if you connect it between the blower and the diffusion pump or the blower and the chamber, then you’re allowing the roots blower to be like an optically dense filter between the leak detector and that backing pump.

And for the two concerns that I mentioned earlier about either back streaming of helium from the leak testing or back streaming hydrocarbons from the vacuum/roughing pump, the optimal location would be to hook it up between the blower and the chamber, or if it’s a diffusion pump, between the blower and the diffusion pump. If you’re hooking it up between the diffusion pump and the roughing pump, you need to make sure that you pump down to your base pressure before you open up the valve from the leak detector to that point. You don’t want to potentially suck any diffusion pump oil into the into the leak detector.

Furnace Connection Points and Hardware (00:15:50)

Doug Glenn: Is there a feed through meant for leak detection built into the furnace, between the blower and the diffusion pump or roughing pump or on the chamber?

Dave Deiwert: There is almost always a connection point where I describe my preferred location, especially with furnaces manufactured in the last twenty years. On new furnaces sold today, it’ll be an NW25 flange, which will match up directly to the leak detector.

With the leak detectors in this industry, we’ll have an NW25 flange, which is a standard vacuum connection. You run a bellows hose from that leak detector to that point on the furnace.

I like to see a manual ball valve that’s always on the furnace at that point. You can put a blank cap on the exposed port on that valve, which can act like a dust cap. It’s always there. This facilitates doing a PM leak check, which we might talk a little bit more about later.

Now, sometimes you may go to hook it up between the blower and the furnace or the blower and the diffusion pump and there’s no connection there.

I’ve seen that, so you have to work with what you’re given. You might well see there’s a port between the blower and the backing roughing pump,

and you can use that. It’s just not the optimal place to put it.

If you put the leak detector directly on the chamber, typically there’s a small port that you can hook up to, now you’re going to be competing in what we call molecular flow with a much larger opening going to the blower. The lion’s share of helium is going to go out that large target to the blower, and you’re not going to get as much helium signal to the leak detector. So, putting the leak detector port basically right into the end of the flow, going to the blower lets you sample the flow going in that direction.

Doug Glenn: Right, which is going to be the bulk of it.

Dave Deiwert: Yes, and you’ll find a faster response time and faster cleanup and recovery of the leak rate signal when you stop spraying the helium by putting it in that location.

PM Leak Checks During Furnace Operation (00:18:05)

Doug Glenn: You briefly discussed conducting PM in the column. Can you walk us through conducting a PM leak check during a live operation of the furnace.

Dave Deiwert: First off, when you’re going to do a preventative maintenance (PM) leak check on the furnace, there are two scenarios. In the first scenario, you’re not running the furnace today. So, you roll the leak detector up and you look for leaks that you may not know are there when they’re smaller and less noticeable, so you can either mark them or repair them at your convenience before they get to be larger and more noticeable, maybe affecting quality of your process.

The second scenario is that you have a very long process. You might have enough time to do a leak check while the furnace is in process. Helium is an inert gas. If you pull a vacuum on your furnace to do some heat treating, and it’s going to be in that vacuum level for an hour or more, this may be plenty of time to do some leak testing. We definitely don’t want to compromise quality. But again, helium is an inert gas, and if you have an experienced person doing this PM leak check in an orderly fashion, it can be done safely.

Basically, you roll the leak detector up to that closed ball valve, and you would have to have the ball valve in place there if you’re doing this during a live process. So you connect the hose from the test part to this closed ball valve. You start the leak detector and put it in test. I suggest that after you put it in test, you ensure you have a good vacuum test level vacuum from the leak detector to the closed valve.

Because we don’t know initially if the vacuum level is different on the other side of the valve,

Heat Treat Radio #123 Host Doug Glenn and Dave Deiwert

I recommend momentarily stopping the test of the leak detector. I think all modern leak detectors have a standby mode so you’re not venting the test for a leak detector. You put it in standby, then you open the ball valve, and the leak detector computer can now see if the vacuum level changed to maybe potentially a level a little higher than what it wants to be at. That allows it to tell itself to pull some more vacuum along with the furnace before we actually open the test valve to the analyzer cell or the mass spectrometer.

If you’re in test, you open the ball valve, and somebody forgets that step, there can be a little vacuum differential and you may shock the leak detector and throw it out of test. This doesn’t hurt the leak detector. You just have to go and press test again. But by putting it into standby and then opening the ball valve, then putting it back into test, this saves you a step.

Once you put it into test, the next thing you’re going to make a note of is the background level of helium before you start spraying helium. I’m a big fan of people who leak test their furnace, or really anything no matter what market is, and take care of their furnaces purposefully.

If you don’t suspect any leaks or it’s a brand new furnace, you can hook your leak detector up and you put it in test, and before you spray any helium, make note of what I call the background helium signal. This is a result of any natural helium that’s in the furnace. There is five parts per million helium in the air we breathe. There’s going to be helium in the furnace, and take note of what that is.

Let’s say you notice you have two times ten minus nine background of helium on the display of the leak detector, and you haven’t sprayed any helium, you can make note of that.

So now you know you’re going to be looking for leaks for some delta change increase of that value. From there, it’s playing the hot and cold game as you pinpoint where the leak isas you spray helium.

You can do this potentially while a furnace is in process. You certainly want everybody to know what you’re doing and have an opportunity to discuss this because it could make people nervous, especially the quality manager or even the production manager. It’s something that should be talked about with the whole team to ensure everybody sees the value in it.

So we spray helium and make a note of anything we see. Next time we have an opportunity, when no production is going on, we can fix that leak at our convenience rather than wait until it might get worse.

Doug Glenn: Certainly we would want to consider whether that should be done with high-value items in the furnace.

Dave Deiwert: Yes, unless everybody is on board and understands, and you’re doing things purposely.

If you are doing a PM leak check on a sensitive process and quality of a product and you’re done testing, that manual ball valve needs to be closed before you do anything else to the leak detector. If you forget, and you press vent on the leak detector, it’s going to try to vent that whole furnace through the little vent valve of the leak detector, and that’s not going to be good.

This whole discussion point is that everybody on the team would need to buy into this idea and be very clear about what we’re going to do, how we’re going to do it.

I’m just suggesting it’s something that can be done, and if you confirm it works for you, it has value. It’s just another option for somebody to optimize the way they take care of their furnace.

Confirming Leak Location Before Repair (00:23:38) 

Doug Glenn: When you’re isolating a leak, how important is it to assume or not assume that you found the leak once you get a reading on the on the meter?

Dave Deiwert: I spend a lot of time on this topic in every class that I teach because nothing is more frustrating than thinking you have found the leak when you haven’t.

Let’s say you think have found the leak on some big 10-inch gate valve. Maybe it’s too heavy for one person you have to have someone to help you take this gate valve off the system. Once you take the gate valve off the system, you put a repair kit in there, clean everything, you put it back on the furnace, and everything’s assembled. You start to furnace back up and you do a leak check and realize you still have the same leak you thought you fixed. There may be other flanges you need to check, which might require more help.

You absolutely, beyond the shadow of doubt, can know that you have found the leak because every time helium is sprayed at that place where you think the leak is, you should get the same response, same response time, same peak leak rate.

If I spray the helium at point A, where I think the leak is at, and I stop spraying, I wait for the leak rate to go back to baseline, then I go back to spray it again. The more work that is involved, the more I’m going to want to duplicate that response and make sure that is where the leak is at.

Last thing you can do, just to be sure, is what I call the “x, y, z axis.” Try to spray helium left, right, up, down, back and forth, just to make sure you’re not getting a better response to something else nearby.

Doug Glenn: By better response, do you mean a higher measurement of helium that comes through or comes through more quickly?

Dave Deiwert: That’s correct. Now, you might have the problem where there are 2, 3, or 4 connections right in the same general area, and it’s difficult to pinpoint where I’m getting I think the same response, no matter where I’m spraying the helium. To remedy this, you can put a barrier between two fittings. This barrier could be plastic, tape, putty, your hand. Try to put some barrier between the two connections so when you spray on one side now, you’re not really getting the same response you were before and can pinpoint the location of the leak more accurately.

This is an important step before you repair or remove something. If you remove a NW25 flange and you’re wrong, there’s not a lot of pain and suffering. But I guarantee you 100%, you can prove to yourself with some patience and some diligence where the leak is before you do the work of disassembly and service.

Doug Glenn: It is better to invest a little time in detection than to repair something that doesn’t need to be repaired or find out later that you fixed the wrong piece.

Dave Deiwert: Absolutely.

Repair vs. Replace: Leak Source Components (00:26:44) 

Doug Glenn: Once you do find the leak and it’s through some sort of a device, whether it’s a feed through or a control or a valve, how do you decide whether to repair that item or replace it?

Dave Deiwert: If the device is something that you can disassemble, and if the manufacturer has a repair kit (a valve is a good example of that), I would recommend that you go ahead with a repair. You have already taken it apart, I would put the part in a repair kit, if you have one, to try to lengthen the time between now and the next time you look at it.

If it’s a piece that has no repair kit, then obviously you will need to repair it or replace it, depending on your skill level and what it is you’re looking at.

If you’re looking at thermocouple and the feed screws on it are leaking, you may be a little limited in what your options are. Can you apply a vacuum-friendly sealant to brush around the feed throughs to see if that would solve the problem? That may be an option. What is the cost of that thermocouple? If it’s a $20 item, I’m probably going to put another thermocouple on there. If it’s a $1,000 item, I might try brushing some vacuum-friendly sealant on and see if that takes care of the problem.

One time, I found a leaking rotary vane pump, back in my field service days.

These all have repair kits where you can replace all the gaskets, the vanes, everything. But I didn’t have one. This was early in my young career. I talked to the factory about getting one and they were going to send one. But I told the client that we had nothing to lose. Let’s open it up, see what we can find. So, we open that pump up, and it looked pretty bad inside, but we cleaned everything up, even the gaskets, put a little vacuum sealant on, and put it all back together. We made it leak tight, and we got it running again. If I had a repair kit, I’m already there, then let’s go ahead and put the repair kit in. But if you don’t have one, there’s nothing wrong with taking it apart and seeing if cleaning and

reassembly gets it going for you.

Rotary Vane Pump Field Advice (00:30:30) 

Dave Deiwert: I’m going to give a little free advice, no extra charge, to people talking about rotary vane pumps. In my career, I’ve come across quite a number of rotary pumps that were having an issue. I can count on one hand, however, how many times I wasn’t able to just clean it, put it back together, and get it going again with fresh oil. And both those times involved a shaft seal leak. So, if you don’t have a shaft seal leak, in my mind, you’ve got nothing to lose by taking a rotary vane pump apart, cleaning it, and putting some fresh oil back in it.

If you’re using solvents, when you take it apart, make sure those are solvents cleared back out of there

because solvents and oil don’t play very nice. You want to make sure that solvents have been removed and degassed from your pump. This may require that you put oil in it, run it for a little while, then flush it, and put some oil in to make sure you don’t have anything remaining behind.

A little willingness to get your hands dirty, open up the rotary vane pump, and a very good chance that you can get it going by just doing that.

Doug Glenn: All right, Dave. Appreciate the good advice and your expertise.

About the Guest

Dave Deiwert has over 35 years of technical experience in industrial leak detection gained from his time at Vacuum Instruments Corp., Agilent Vacuum Technologies (Varian Vacuum), Edwards Vacuum, and Pfeiffer Vacuum. He leverages this experience by providing leak detection and vacuum technology training and consulting services as the owner and president of Tracer Gas Technologies.

Learn more about Dave from Heat Treat Today’s July Digital Edition’s Meet the Consultant page.

For more information: Contact Dave at ddeiwert@tracergastechnologies.com

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Heat Treat Radio #123: Helium Leak Detection Tips for Vacuum Furnace Operators Read More »

How To Find Both Real and Virtual Vacuum Leaks

April 22, 2025 / Featured, HEAT TREATING EQUIPMENT, Manufacturing Heat Treat Technical Content, VACUUM FURNACES, VACUUM FURNACES TECHNICAL CONTENT

In this Technical Tuesday installment, Thomas Wingens, Founder & President, WINGENS CONSULTANTS; Dr. Dermot Monaghan, Managing Director, and Dr. Erik Cox, Manager of New Business Development, Gencoa, train readers for finding both real and evasive virtual vacuum leaks.

Leak detection is difficult enough with a “real” leak, but “virtual” leaks present their own challenges. To enhance cost savings and further process efficiencies, it’s essential to have leak sensor technology that can effectively monitor the vacuum chamber and pinpoint these problematic leaks.

This informative piece was first released in Heat Treat Today’s March 2025 Annual Aerospace Heat Treating print edition.

Uncontrolled impurities in a vacuum furnace can significantly affect the quality of vacuum heat treating and brazing processes. They can compromise the integrity of the processed material, leading to defects, reduced performance, and increased costs.

Real vs. Virtual Leaks

Real leaks are physical openings in the vacuum system that allow external gases to enter the chamber. These can be cracks, weld failures, improperly installed fittings, faulty seals from damaged or worn O-rings on doors, rotating assemblies, or other components of the vacuum furnace.

The impact on quality includes:

Oxidation and contamination: Real leaks introduce atmospheric gases (like oxygen, nitrogen, and moisture) into the vacuum chamber, which can lead to oxidation of the materials being treated or brazed, as well as other forms of contamination.
Inconsistent results: The presence of unwanted gases can interfere with the chemical processes required for proper heat treatment or brazing, leading to inconsistent metallurgical results.
Reduced mechanical properties: Contamination and oxidation can weaken the materials being processed, leading to defects and reduced mechanical properties of the final product.
Difficulties in achieving desired vacuum: Real leaks can prevent the system from reaching or maintaining the necessary vacuum levels, leading to longer cycle times or failed processes.

Figure 1. Pumping times based on residual water vapor

Real leaks are often easier to detect, especially larger leaks, which can be identified by hissing sounds or the inability of the furnace to pump down. They can be located using methods such as pressure rise tests, solvent detection, or helium leak detectors.

Virtual leaks, however, are much harder to detect as they are not physical openings but rather trapped volumes of gas within the vacuum system that slowly release over time. These trapped volumes are typically found in blind holes, porous materials, or unvented components. Even more problematic are leaks from internally sealed systems, such as water cooling or hydraulics. Leaks from these areas cannot be detected via a leak detector, as the water or oil media can “mask” the leak site and prevent the tracer gas from penetrating.

Aside from increasing the pump time it takes to reach the required vacuum levels, leaks can be a continuous source of contamination within the vacuum chamber. Outgassing can be especially problematic during the heating cycle as it can lead to large vacuum “spikes” or a rise in pressure, affecting the stability of the process environment. Gases released from virtual leaks can contaminate the materials being treated. For example, residual solvents or water vapor from cleaning or incomplete drying can lead to contamination and outgassing. It can be small volumes of air or gas trapped at the bottom of threaded holes or trapped volumes between two O-rings that are not properly vented. Also, outgassing from various hydrocarbons in porous materials such as low-density graphite or powder metallurgy components can release unwanted gases when heated up.

They usually become apparent during the pump-down cycle when the ultimate pressures are not reached or when it takes a long time to reach blank-off pressure. Traditional leak detectors will not pick up virtual leaks.

Detecting Virtual Leaks Accurately

However, residual gas analysis (RGA) and remote plasma emission monitoring (RPEM) can identify virtual leaks by monitoring the composition of gases in the chamber. RPEM offers advantages over traditional quadrupole mass spectrometry (QMS) RGA, particularly in large vacuum systems. Unlike RGAs, RPEM technology operates over a much wider pressure range (50 mbar to 10-7mbar) without requiring additional pumps. The RPEM detector is located outside the vacuum chamber, making it more robust against contamination and high pressures, which commonly damage RGA detectors. This external setup also reduces maintenance needs, as RPEM avoids frequent rebuilds required for traditional RGAs in volatile environments.

Figure 2. Functionality and pressure range of the OPTIX sensor

An example of this newer sensor is the OPTIX, which enables real-time monitoring and process control by providing immediate feedback to maintain chemical balance and ensure product quality. By identifying specific gas species, the sensor allows versatile leak detection with faster problem-solving and continuous system monitoring. Determining the nature of the gas leak will be a clear indication of where the problem originates. Also, whether the gas levels are stable or decreasing will point towards either a real leak or outgassing problem. Unlike RGAs, this sensor does not require highly skilled staff for operation, further lowering the technical burden. Its effectiveness in harsh environments with volatile species makes it a robust and versatile tool for industrial vacuum processes.

Conclusion

By understanding the differences between real and virtual leaks, and their specific impacts on vacuum heat treating and brazing, operators can implement more effective detection and prevention strategies, ultimately leading to improved product quality and process efficiency.

Attention to design, manufacturing, and assembly processes is critical to minimize the occurrence of leaks. This includes proper venting of components, use of appropriate sealing methods, and high-quality welding. Ensuring that components and materials are properly cleaned and dried before being introduced into the vacuum system can reduce outgassing.

Regular leak checks, including leak-up-rate tests, are essential for identifying both real and virtual leaks. Advanced gas analysis techniques are very useful for identifying the type of leak and its source through analysis of the gases in the vacuum chamber. Th e method provides continuous on-line monitoring, rather than periodic leak testing when there is a “suspicion” of a problem.

In the demanding environment of vacuum heat treating and brazing, the OPTIX sensor’s advanced technology not only simplifies leak detection and process control, but also delivers significant cost savings through reduced maintenance and operational expenses. Adopting this type of technology gives operators the ability to enhance vacuum system performance, improve product quality, and achieve greater process efficiency.

About The Authors:

Thomas Wingens
Founder & President
Wingens Consultants
Industrial Advisor
Center for Heat Treating Excellence (CHTE)

Thomas Wingens is the Founder and President of Wingens Consultants, and has been an independent consultant to the heat treat industry for nearly 15 years and has been involved in the heat treat industry for over 35 years. Throughout his career, he has held various positions, including business developer, management, and executive roles for companies in Europe and the United States, including Bodycote, Ipsen, SECO/WARWICK, Tenova, and IHI-Group.

For more information: Contact Thomas Wingens at thomas@wingens.com

Dr. Dermot Monaghan
Managing Director
Gencoa

Dr. Dermot Monaghan founded Gencoa Ltd. in 1994. Following completion of a BSc in Engineering Metallurgy, Dermot completed a PhD focused on magnetron sputtering in 1992 and went on to be awarded with the C.R. Burch Prize from the British Vacuum Council for “outstanding research in the field of Vacuum Science and Technology by a young scientist.” He has published over 30 scientific papers, delivered an excess of 100 presentations at international scientific conferences, and holds a number of international patents regarding plasma control in magnetron sputter processes.

Eric Cox
Manager, New Business Development
Gencoa

Dr. Erik Cox is a former research scientist with experience working in the U.S., Singapore, and Europe. Erik has a master’s degree in physics and a PhD from the University of Liverpool. As the manager of New Business Development at Gencoa, Erik plays a key role in identifying industry sectors outside of Gencoa’s traditional markets that can benefit from the company’s comprehensive portfolio of products and know-how.

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