In this Technical Tuesday installment, Jim Roberts of U.S. Ignition entertains readers in a Combustion Corner editorial about how fuel sources became more affordable over time and aspects of combustion burner design. Stick around for his side story on the “innovative” use of bedposts.
This editorial was first released inHeat Treat Today’sOctober 2025 Ferrous/Nonferrous print edition.
A furnace guy walks into a heat treat facility and sees burners everywhere. Furnace guy says to the faces in the room, “Why did you pick those types of burners?” Thinking this is a trick question, the heat treaters respond, cautiously, “To make things hot?” Of course, they are correct, because making fire and heat is the name of the game, right?
But as we have considered burner styles, designs, flame shapes, and air delivery types with our last couple of Combustion Corner columns, I suspect there was a good deal more analysis given to the selection of burners.
To appreciate the history of burner design, “furnace guy” should realize why burners evolved in the first place: fuel source. When the first burners were starting to be used on box furnaces, they used oil, kerosene, and fuel that had to be pumped. Over the years, many different fuels have been used. Yet, we have a tendency to think of gaseous fuels as the only option for burner performance.
Bedpost Burners
I recall the first time I got called into a facility to try and improve the performance of the furnaces (yep, I truly am a furnace/burner guy). It was a big box furnace that could handle 3-ton quench and temper loads. At that point, I was unaware of the multiple types of burners that were out in the market.
The owner of the shop opened the furnace door for me to see the combustion system. I stared. Sticking into the walls of this big box furnace were bedposts. These “burners” were purchased at 50¢ a post from some hotel auction, and they had about 50 spare posts to boot.
Grinder slots had been cut into the top of these posts. Refractory had been mudded into the mounting blocks to protect the fuel feed, which was being forced, or should I say blown, in through the bed posts and atomized by the pressure of being squeezed through these slots in the knob at the top of the posts!
The fuel? Diesel fuel. Regular, old, out-of-the-pump diesel fuel. Or kerosene, for that matter. I was told the system could also use fire pulverized coal, sucked into the bedpost by pitot feeds of compressed air. They lit the burners with burning oily rags tossed into the chamber and quickly opened the valves controlling the fuel.
I was there to sell new modern high-efficiency gas burners.
I declared that this was antiquated, unsafe, archaic, dirty, and said about a thousand other denigrating comments.
The owner of this heat treat said, “Yep, it’s all those things, and more!” He continued, “It’s also reliable, simple, and predictable.” He mused, “I suppose that that thing hasn’t really broken down or shut off in the 25 years since we built it!”
I’m a fairly quick study and surmised that I was not going to make this sale. Duh! This furnace had everything they needed. And the gas system I was going to propose was going to be expensive.
A Burgeoning Gas Industry and Our Next Column
That furnace was still running when I made a move to another city some 10 or so years later.
Eventually, the gas industry that cropped up made fuel cheap…and I mean cheap. I thought, “I bet that guy and his accursed bedpost burners will talk to me now!” So, I went back, and that fella said, “Yeah, we got out of the business that used that old process and moved on. We’d be glad to talk about modernization.” And we did.
That same outfit that operated bedposts for burners for 50 years became a vanguard for modern efficiency and process improvement.
Natural gas as a fuel source is quite modern. Nowadays, that is essentially the truth: natural gas and sometimes other gaseous equivalents tend to be the most widely used fuels in the industrial world.
When looking at the rapid developments of burner configurations and why they developed, it is best first to understand some of the history of these developments. See you in the next installment to talk about the history of the industrial gas industry.
About The Author:
Jim Roberts President US Ignition
Jim Roberts president at U.S. Ignition, began his 45-year career in the burner and heat recovery industry focused on heat treating specifically in 1979. He worked for and helped start up WB Combustion in Hales Corners, Wisconsin. In 1985 he joined Eclipse Engineering in Rockford, IL, specializing in heat treating-related combustion equipment/burners. Inducted into the American Gas Association’s Hall of Flame for service in training gas company field managers, Jim is a former president of MTI and has contributed to countless seminars on fuel reduction and combustion-related practices.
For more information: Contact Jim Roberts at jim@usignition.com.
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 Groupexplains 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.
Preparing for mixing Source: Plibrico
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 wasinitially published in Industrial Heating. All content here presented is original from the author.
Heat Treat Todaypublishes twelve print magazines a year and included in each is a letter from the editor. This letter is a pre-release from the December 2025 Annual Medical and Energy Heat Treat print edition. In today’s letter,Bethany Leone, managing editor at Heat Treat Today, shares about the ASM Heat Treat show of 2025.
Attending the bi-annual Heat Treat show is always a thrill. The ASM Heat Treat Society did not disappoint, bringing a full line up of technical sessions and engaging panels to attend between walking the busy show floor, itself packed with cutting edge research presentations and informative booths of key players. I had the opportunity to attend more sessions than usual this year to hear what concerns in industry were being raised at this event.
On Monday, October 20, ASM President Dr. Navin Manjooran, chaired the first ever Executive Leadership Forum, bridging the concerns and forecasts of industry leaders with the bold training methods of frontline academic leaders. The event was specifically hosted for the IMAT conference attendees at the collocated 33rd Heat Treating Society Conference and Exhibition.
Dr. Manjooran underlined the intent of creating stronger collaborations between these two groups, with the first moderator, Renee Parente, director of Technology and Product Engineering at Advanced Micro Devices (AMD), further emphasizing the goal of accelerating innovation through open discussions like these.
Industry Panel
At this forum, the first panel included a Q&A portion moderated by Renee Parente with the following four industry panelists:
Dr. Aziz Asphahani, FASM, chairman and CEO of Questek Innovations
Dr. David Furrer, FASM, principal fellow and discipline lead for materials and processes at Pratt & Whitney
John R. (Chip) Keough, PE, FASM, chairman and president at Lightspeed Concepts/Joyworks LLC
Dr. Dehua Yang, FASM, president at Ebatco
Screenshots from the ASMExecutive Leadership Panel handout Source: ASM International
From this panel came key thoughts on how research in the business world was being developed to further commercial efforts. First, there was a consensus that corporations were investing in research internally but were instead looking to start-ups to absorb the energies of research and development needs. While academic-industry partnerships were valuable, the concern over IPs was reviewed with Dr. Furrer adding that it is commitment to collaborative internal research efforts and external research industry partnerships that is most meaningful. He also added that the new generation of engineers are entering the workforce with new tools of industry at the ready to implement, and this shift needs to be welcomed to keep pace with the speed of innovation.
Another important thread of discussion in this panel was the need to both accelerate the development of higher performance materials (Dr. Asphahani), as well as implement this development in a connected manner across engineering counterparts, like the quality, manufacturing, and design departments (Dr. Furrer) for effective product development.
Academic Panel
The academic panel revealed specifics on exciting current and developing efforts to train the rising workforce. Dr. Viola L. Acoff, the dean of engineering at the University of Mississippi, passionately shared the success of her breakthrough course design to retain freshmen metallurgy students through a hands one MTE 101 course, which includes access to a fully functioning foundry and efforts to grow already present real-world industry experience through industry-sponsored programs.
Screenshots from the ASMExecutive Leadership Panel handout Source: ASM International
While the panel acknowledged the ongoing efforts to prepare students to use AI and other technologies of Industry 4.0 (and 5.0), there was a mixture of other emphases, including:
the “plug-and-play” graduate who does not need remediation training at their first job (especially emphasized by Dr. Christopher Berndt, distinguished professor, Surface Science and Engineering at Swinburne University of Technology)
a focus on developing materials engineers who think critically
a close look at the publication system, with some specifically advocating the need to rethink this system as the barometer for engaged students and commercially focused research
The four-person academic panel was completed by Dr. Hanchen Huang, FASM, dean of Engineering and endowed chair professor at Oklahoma State University, and Dr. David B. Williams, FASM, dean emeritus at The Ohio State University. The moderator was Dr. Zi-Kui Liu, FASM, Dorothy Plate Enright Professor in MSE at The Pennsylvania State University.
Audience
I sat in a room amidst several dozen heat treat decision makers from both the commercial and teaching ground of heat treat, ranging from student and early career to research veteran and recently retired. Audience members asked their questions after both of the panels and mingled after the session to share a few words amongst ourselves and the generous speakers.
Clearly, concern for the next generation of materials experts to meet industry needs — both in training and in availability of personnel — was of primary importance. Be it the question of how industry was investing in secondary and primary education interventions or a side discussion questioning how the leaders of both panels were driving young people toward entrepreneurial competition, the room buzzed with interest.
Summary
One comment Dr. Furrer shared outside of the panel session was his interest in how the focus of academia was shaping the opportunities available to upcoming industry leaders and engineers.
Despite the government panel being unable to participate in the forum due to the ongoing government shutdown, this forum proved to be emblematic of Dr. Manjooran’s summary of ASM’s most important attribute: the ability through connections — memberships, partnerships, etc. — to advance materials worldwide.
In today’s News from Abroad installment, we highlight The Bright World of Metals 2027 GIFA, METEC, THERMPROCESS and NEWCASTconferences, an aluminum exctrusion company’s recent acquistion of Induction Professionals, and a twelve month power deal for an Australian aluminum smelter.
Heat TreatTodaypartners with two international publications to deliver the latest news, tech tips, and cutting-edge articles that will serve our audience — manufacturers with in-house heat treat. Furnaces International, a Quartz Business Media publication, primarily serves the English-speaking globe, and heat processing, a Vulkan-Verlag GmbH publication, serves mostly the European and Asian heat treat markets.
Global Metal Fairs Open for Registration
Lively atmosphere at the Bright World of Metals in Düsseldorf: GIFA, METEC, THERMPROCESS and NEWCAST will once again unite the key sectors of the metal and foundry industry in 2027. (Source: Messe Düsseldorf / C. Tillmann) Source: Heat Processing
“Four world-leading trade fairs, one common goal: to shape the future of the global metal and foundry industry. From 21 to 25 June 2027, ‘The Bright World of Metals’ will bring together international market leaders, hidden champions and newcomers in Düsseldorf — from iron and steel to aluminum and other non-ferrous metals. The focus is on the central topics of the industry: Green Transformation — Sustainability and Decarbonization — Digitization and Automation, Resource Efficiency and Circular Economy, Young Talent as well as Global Networking and Knowledge Transfer.
“These topics shape the programme, the exhibition areas and forums and form the framework for innovation, transformation and future viability of the international metal and foundry industry. Companies can now register online and secure their place.”
Extrutec North America acquires Induction Professionals
The new company will be situated in Induction Professionals former facility in Youngstown, Ohio.
Source: Furnaces International
“Aluminium extrusion company Extrutec North America, has acquired Induction Professionals, leading to the formation of the new company Induction Professional Solutions (IPS). The acquisition will combine Extrutec’s energy efficient technology with Induction Professionals extensive experience to provide customers with advanced heating solutions.
“Uwe Günter, managing partner of Extrutec, said: “We are thrilled to welcome Induction Professionals assets and expertise into the Extrutec family. This is an exciting and strategic step for our company. By integrating Induction Professionals’ capabilities into our North American operations, we are well-positioned to offer a comprehensive portfolio of the most modern, energy-efficient induction heating solutions. We are committed to building on the foundation of trust and quality that Tom Kearney and his team have established.”
The future of the Rio Tinto-owned smelter based in northern Tasmania, was put in jeopardy as its 10-year power agreement was set to expire on 31 December. Source: Furnaces International
“Bell Bay Aluminium has, in-principle, agreed a 12-month extension to their deal with Hydro Tasmania. The future of the Rio Tinto-owned smelter based in northern Tasmania, was put in jeopardy as its 10-year power agreement was set to expire on 31 December, reported ABC.
“In a statement on their website, the Australian Aluminium Council, said: ‘Today’s announcement between the Tasmanian Government and Rio Tinto’s Bell Bay Aluminium to extend the power arrangements until December 2026 is a welcome stepping stone towards what will hopefully be a long-term solution. This news will be welcomed by the employees and people of Tasmania who rely on the smelter for jobs, its local economic contribution, and the vital role it plays in the Tasmanian grid.’”
Hiperbaric, the Spanish manufacturer of high-pressure technology, will present its range of hot isostatic presses (HIP) at Formnext as the solution to densify critical components and eliminate porosity in 3D-printed parts.
As the global additive manufacturing (AM) ecosystem gathers for its annual event, Hiperbaric’s presence underscores a commitment to providing technology that maximizes the performance of 3D-printed metal and ceramic parts. HIP technology is key to improving the mechanical properties and structural integrity of critical components.
HIP 38 press for thermal post processing of materials Source: Hiperbaric
“For an industry seeking nanometric perfection, eliminating internal porosity is not an option, it is a necessity,” says Andrés Hernando, CEO of Hiperbaric. “HIP is the technological enabler that dramatically improves the mechanical properties and structural integrity of critical components, making AM viable for mass production in the most demanding sectors.”
Hiperbaric’s technology directly addresses the primary challenge of metal AM. Processes such as Selective Laser Melting (SLM) or Electron Beam Melting (EBM) create parts layer-by-layer, a method that can inherently leave residual micro-porosity. While this may be irrelevant for a prototype, for a turbine blade, a medical implant, or a high-performance racing engine part, this porosity represents a potential failure point.
HIP is the post-processing step that elevates an AM part to the quality of a forged material. It transforms a porous or micro-cracked material into a solid, monolithic, and homogeneous structure, guaranteeing it meets the strictest mechanical specifications.
How Hot Isostatic Pressing Works
HIP is an advanced manufacturing and heat treatment process that subjects components to two simultaneous forces: high temperature and high isostatic pressure. The component is placed inside a high-pressure vessel. This chamber is heated to temperatures that can reach 2,000°C (3,632°F) and is simultaneously pressurized with an inert gas (usually argon) to pressures of up to 2,000 bar (29,000 psi).
Hiperbaric’s innovation and experience in high-pressure processing has enabled the manufacture of modern HIP equipment, improving performance and reducing costs. Its wire wound vessel technology not only has advantages from a safety and reliability point of view, such as increased service life or the “leak-before-break” design that prevents catastrophic failures, but also provides advantages from a thermodynamic point of view.
Rocket engine treated by HIP technology
Being a wire wound vessel, the cooling channels can be placed very close to the vessel wall and therefore very close to the hot zone, allowing the vessel to act as a heat exchanger, enabling fast cooling inside the equipment. Through a fan and valves located in the lower part of the oven, forced convection is activated by circulating the hot gas through a heat exchanger located in the upper cap, which exits and descends in contact with the wall of the vessel (which is cooled) and re-enters the oven.
The ability to fast cool within HIP equipment, in addition to the increased productivity, reducing production times and energy consumption – which translates into savings – has a series of advantages from a material science perspective, improving the microstructure and physical properties. Thanks to fast cooling, it is also possible to carry out heat treatments within the same equipment, opening the door to combined cycles (Combined HIP – Heat Treatment, CHIP-HT).
The effect is two fold:
Porosity Elimination: The combination of heat and pressure applied uniformly from all directions (“isostatic”) causes internal pores and microscopic voids to collapse and diffusion-bond.
Full Densification: The result is a component that achieves 100% theoretical density. This process drastically improves ductility, fatigue strength, impact resistance, and fracture toughness.
Hiperbaric has developed a cutting-edge range of HIP presses specifically designed to meet the exacting needs of the aerospace, energy, medical, and metallurgy industries.
A Technological Milestone: HIP Reaches Taiwan
Hiperbaric recently marked an industrial milestone by supplying the first 100% Spanish-developed HIP system to Taiwan. This equipment is Hiperbaric 93 HIP, destined for Taiwan’s highly demanding aerospace industry, serves as a crucial validation.
Heat Treat Today has gathered the four heat treat industry-specific economic indicators for November 2025. The November industry-specific economic indicators reinforce the overall trend toward growth that began in September of 2025.
November’s industry-specific economic indicators showed all four indices in growth. The Inquiries stayed in growth, rising to 56.5 (from 50.6 in October). Bookings rose to 55.0 (from 50.7 in October). The Backlog index rose out of contraction to 55.0 (up from 47.5 in October). Finally, the Health of the Manufacturing Economy index remained in growth at 56.5 (up from 52.8 in October).
All of the graphs suggest that the undercurrent of growth, which began in late summer, is continuing to rise as we look to the end of the year.
The results from this month’s survey (November) are as follows: numbers above 50 indicate growth, numbers below 50 indicate contraction, and the number 50 indicates no change:
Anticipated change in Number of Inquiries from October to November:56.5
Anticipated change in Value of Bookings from October to November: 55.0
Anticipated change in Size of Backlog from October to November: 55.0
Anticipated change in Health of the Manufacturing Economy from October to November: 56.5
Data for November 2025
The four index numbers are reported monthly by Heat Treat Today and made available on the website.
Heat TreatToday’sEconomic Indicatorsmeasure and report on four heat treat industry indices. Each month, approximately 800 individuals who classify themselves as suppliers to the North American heat treat industry receive the survey. Above are the results. Data started being collected in June 2023. If you would like to participate in the monthly survey, please click here to subscribe.
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 inHeat Treat Today’sNovember 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.
Interior of vacuum furnace
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.
Vacuum furnace hot zone
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.
Alleima, a manufacturer of steel components and special alloys, will receive a new tube annealing furnace. The electric atmospheric furnace line is intended for bright annealing of high-alloy tubes and will be used in the production of nuclear applications components.
SECO/WARWICK is providing the furnace as their 5,000th device.
The tube annealing system Source: SECO/WARWICKPiotr Skarbiński Vice President of Aluminum and CAB Products Segment SECO/WARWICKMagnus Mellberg Production Unit Manager Alleima Source: LinkedIn
“Our partnership with SECO/WARWICK has lasted for many years. We are delighted that we could celebrate it in a special way, as our impressively large tube annealing line (over 140 meters long – 460 ft) happens to be the 5,000th SECO/WARWICK device. We feel that together we are creating not only a remarkable history, but also the future as this solution will help us spread our wings,” said Magnus Mellberg, production unit manager at Alleima.
“The furnace was created specifically for this partner’s needs. It will allow them to increase production capacity…This is important as the demand for high-alloy components in this market has increased. It is an unusual construction, verified through analysis and simulations, and implemented in reality. It offers very good technological results after the annealing process,” explained Piotr Skarbiński, vice president of the Aluminum and CAB Business Segments at the SECO/WARWICK Group.
Press release is available in its original form here.
Solar Atmospheres has expanded its operations with an additional all-metal hot zone furnace. The new system significantly expands the company’s capacity to heat treat highly sensitive materials such as precipitation-hardened stainless steels, nickel-chrome-based superalloys, titanium, and niobium. The new unit is installed at their Hermitage, Pennsylvania facility and will meet the stringent demands of the aerospace and medical industries.
Additional all metal hot zone furnace for Solar Atmospheres Source: Solar Atmospheres
Michael Johnson, Sales Director at Solar Atmospheres of Western Pennsylvania, stated: “The all-metal vacuum furnace plays a critical role in delivering the purest possible processing environment. This level of cleanliness and control results in pristine end products that meet the most demanding industry standards. We’re proud to partner with the engineers at Solar Manufacturing to bring this advanced technology to fruition.”
The furnace incorporates strategically placed isolation valves, an oversized main valve, a high-capacity diffusion pump, and a polished stainless-steel chamber. Capable of achieving vacuum levels below 5 x 10⁻⁶ Torr, the system ensures bright, contamination-free results.
Press release is available in its original form here.
