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Métodos para la medición de la austenita retenida

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La mayoría de quienes aplican el tratamiento térmico reconocen la importancia de medir la austenita retenida (RA, por sus siglas en inglés); no obstante, muchos optan por no realizar estas mediciones por razones de tiempo y/o de los costos asociados. Este artículo explica los motivos por los cuales se deben practicar las mediciones RA, los factores a favor y en contra de las tecnologías de medición tradicionales y los beneficios de realizar la medición en la planta misma, utilizando tecnologías más avanzadas.

This informative piece was first released in Heat Treat Today’s March 2025 Aerospace Heat Treating print edition. To read the article in English, click here.

La importancia del porcentaje de austenita retenida

Antes de entrar a examinar algunas metodologías de medición, es necesario entender lo básico en relación a la austenita retenida, al igual que la importancia que reviste el porcentaje de la misma (%RA).

Austenita retenida (RA) es el nombre que se le da a la austenita que durante el proceso de templado no se transforma en martensita. En términos sencillos, la austenita retenida (figura 1) ocurre cuando el acero se ha templado sin llegar de manera contundente a la temperatura de acabado de la martensita (Mf); es decir, la temperatura ha estado por encima de lo requerido para permitir la formación de martensita al 100%. Debido a que la Mf está por debajo de la temperatura ambiente en la mayoría de las aleaciones que contienen más del 0.30% de carbón, se pueden presentar cantidades significativas de austenita retenida en la martensita a temperatura ambiente. (Herring, Atmosphere Heat Treatment).

Al tratarse del %RA, con frecuencia existe un equilibrio muy sensible entre sus efectos benéficos (el aumento en la durabilidad de ciertos componentes manufacturados) y sus atributos negativos (la creación de piezas susceptibles de fracturas y averías). Por tal motivo es de crítica importancia que los tratadores térmicos logren el %RA óptimo para la aplicación deseada.

Por ejemplo, en las industrias de la aeronáutica y la astronáutica, con frecuencia se especifica que los niveles de RA sean inferiores al 8%, y para piezas como los cojinetes y los actuadores lineales, se requiere un RA por debajo del 3%, lo más cercano posible a cero. No obstante, en otras aplicaciones, como por ejemplo los engranajes grandes para generadores de energía, energía eólica y plataformas de rendimiento, se ha identificado que un RA en el rango del 15-30% reviste mayores beneficios. (Errichello et al., “Investigations of Bearing Failures”). De igual manera, un alto % RA es una ventaja en el caso de cojinetes que vayan a entrar en contacto con lubricantes contaminados.

Figura 1. Microestructura en la superficie de la trayectoria de un cojinete de rodamiento 12CrNi3 (o SAE/AISI 9310) compuesto por martensita templada en la que se evidencia austenita retenida (áreas blancas)

Marco DeGasperi, gerente técnico de Verichek, se pronunció al respecto señalando que el %RA es de crítica importancia para los inyectores de combustible, para piezas pequeñas en aplicaciones médicas y para aplicaciones de alto nivel y alto volumen tales como las placas de desgaste en la industria minera. Lo resumió afirmando: –Cuando tu ejercicio se trate de someter a presión y movimiento cualquier dispositivo de calibración fina…si utilizas la palabra “precisión” para darte a conocer, vas a querer hacerte a una [herramienta de medición del %RA].

Las mismas características que le dan a la austenita retenida muchas de sus propiedades particulares, son a la vez las respons ables de significativos problemas de funcionamiento. Sabemos que la austenita es la fase normal del acero a altas temperaturas, mas no a temperatura ambiente. Debido a que la austenita retenida existe por fuera del rango normal de su temperatura, es metaestable, lo que quiere decir que, cuando entre en funcionamiento, los factores como la temperatura, el estrés, y aún el tiempo, harán que se transforme en martensita no revenida. Es más, junto con dicha transformación se dará un cambio en el volumen (aumentará) generando un alto grado de estrés interno en el componente y provocando muchas veces la formación de grietas lo que podrá llevar a que las piezas fallen en el campo.

El % RA también es importante, no solo por el impacto sobre la estabilidad dimensional, sino además por las propiedades mecánicas tales como el límite elástico, la resistencia a la fatiga, la tenacidad, y la manejabilidad. (Herring, Atmosphere Heat Treatment). A manera de ejemplo, DeGasperi identifica en la industria automotriz las consecuencias de un %RA demasiado alto o demasiado bajo: –Hablemos de las piezas en una transmisión o en una caja de transferencia; aquí es donde se dan los casos en los que se empiezan a romper los cojinetes, o terminas viéndote en la obligación del retiro masivo del producto del mercado. Y por lo general toda la cadena de suministro identifica al anterior como el culpable cuando ninguno en toda la cadena se ha tomado la molestia de probar las piezas por sí mismo.

Por el contrario, en algunos casos, la RA diseminada en pequeñas cantidades aporta para que el material resista la propagación de fracturas por fatiga y disminuye el estrés por fatiga en el contacto de rodamiento, así que lograr el correcto equilibrio en la cantidad de RA es importante en muchas aplicaciones. Además, el % justo de RA es esencial para el control de calidad, al igual que para evitar problemas de seguridad y retiros masivos del mercado. El debido control y la medición precisa del % RA en las aleaciones de acero es un punto crítico para garantizar la calidad y la seguridad de los componentes terminados, salvaguardando así la reputación y el margen de ganancia tanto de los tratadores térmicos como de los fabricantes.

Métodos de medición de RA

El medir con precisión la RA es de vital importancia para establecer si existe el balance correcto entre la austenita retenida y la martensita en determinado componente. Los tratadores térmicos tienen a su disposición varias metodologías para esta medición, cada una con sus respectivas ventajas y desventajas. Para el tratador térmico entender la importancia de medir el % RA representa tan solo una parte de la batalla ganada, mientras que la otra parte se gana cuando se logra identificar un método de medición que sea rápido, preciso y rentable.

La difracción de rayos-X: el mejor y más preciso de los métodos

Figura 2a. Una unidad de sobremesa ArexD de GNR

La difracción de rayos-X, utilizada para identificar y cuantificar las fases en un material, se considera el método más preciso de medición de RA en acero ya que logra establecer los niveles de RA hasta el rango aproximado de 0.5-1% (GNR, “AreX Diffractometer,” 3). En la difracción de rayos-X, las diferentes fases cristalinas demuestran diferentes patrones de difracción, lo que permite que sean identificadas y medidas. Además del análisis de fases, la difracción de rayos-X se puede utilizar para analizar car acterísticas microestructurales tales como la textura, el esfuerzo residual y el tamaño del grano.

Hoy en día, la difracción de rayos-X es una solución segura y no-destructiva que permite valorar una región mucho más amplia que la de varios de los otros métodos disponibles, sin necesidad de gran preparación ni análisis de la muestra, haciendo de ésta una solución más eficiente y efectiva. Es la tecnología más opcionada para una empresa que requiera valorar la RA con un resultado esperado inferior al 10%,

La actual generación de difractómetros de rayos-X ostenta un diseño de sobremesa con un peso aproximado de 25 libras. Existen modelos con costos inferiores a los USD $100.000, lo que los hace rentables frente al costo de un difractómetro tradicional (USD $200.000) que tenía además la desventaja de presentar dificultades cuando la muestra tuviera fases y reflexiones adicionales, ya fuera por el tamaño del grano, por los carburos o por las texturas que pudieran provocar disturbios y variaciones en la medición. La nueva generación de equipos de rayos-X logra superar estos obstáculos utilizando múltiples picos de difracción para minimizar los efectos de la orientación preferida y detectar la interferencia de los carburos.

Figura 2b. Una unidad de sobremesa ArexD de GNR

Las máquinas modernas de difracción de rayos-X tienen la capacidad de recoger hasta siete picos de difracción (tres para la fase ferrítica/martensítica y cuatro para la fase austenítica) para luego establecer la concentración de porcentaje por volumen de RA en la muestra al comparar las intensidades de los picos y analizar las relaciones entre éstos de acuerdo con el ASTM E975-22 (práctica estándar para la determinación por rayos-X de austenita retenida en acero con orientación cristalográfica cercana a la aleatoria).

No es complicado usar los equipos modernos de difracción de rayos-X. En menos de tres minutos se logra la medición con tan solo ubicar la muestra en la máquina y oprimir el botón de inicio. Estos difractómetros realizan mediciones en muestras de diferentes tamaños y se valen de software intuitivo, dando lugar a que cualquier técnico, tenga o no experiencia previa en metalurgia o difracción, efectúe la medición de manera rápida, precisa y eficiente.

La microscopía óptica: un método a prueba del tiempo

La RA se puede medir de manera metalográfica con un microscopio óptico. En la mayoría de los casos, un metalúrgico con experiencia puede establecer el %RA en el rango hasta del 10-15%, lo cual es más que suficiente para muchas aplicaciones, con el beneficio adicional de que también caracteriza la microestructura.

Este método, que implica establecer la fracción de austenita mediante el contraste derivado del comportamiento de grabado o morfología, es de bajo costo; sin embargo, puede ser demorado. En libros de referencia existen tablas y diagramas que ayudan a determinar el porcentaje de austenita retenida utilizando métodos comparativos. La microscopía óptica es subjetiva ya que depende del individuo y la interpretación que haga de la muestra bajo el microscopio.

Figura 3. Ejemplo de la técnica para medir los picos de %RA

Métodos alternos

Los tratadores térmicos también disponen de otros varios métodos de medición de la RA. Entre los más comunes se encuentran:

La inducción magnética: Aquí se magnetiza una muestra al punto de saturación y se mide la polarización de saturación. Con esto, se calcula la diferencia entre la saturación medida y la saturación teórica de la RA utilizando la ecuación.

La inducción magnética no es destructiva y ofrece un rango más alto y amplio que el de la microscopía óptica (1-30%). Sin embargo, al ser una medición de volumen, es necesario que el instrumento sea calibrado a los materiales específicos, junto con sus tratamientos térmicos y geometrías, lo cual exige mucho tiempo y depende en un alto grado de la habilidad del técnico.

Difracción de electrones por retrodispersión (EBSD, por sus siglas en inglés): Utilizar este método de medición de RA implica ubicar la muestra en un microscopio electrónico de barrido (SEM, por sus siglas en inglés) para caracterizar la estructura cristalográfica al igual que la microestructura. Las mediciones de RA con base en esta técnica no suelen ser muy precisas y dependen de la correcta preparación de la muestra. Adicionalmente, es un método destructivo y arroja una medida sobre un volumen muy pequeño.

En conclusión

El medir acertadamente el nivel de austenita retenida permite que tanto el ingeniero de diseño como el metalúrgico maximicen los efectos benéficos que ofrece, al mismo tiempo evitando sus consecuencias negativas. El tratador térmico, por su parte, deberá tener en cuenta la química del material y las variables del proceso de tratamiento térmico tales como la temperatura de austenización, la rapidez de enfriamiento, los tratamientos criogénicos o de congelación profunda y las temperaturas de templado.

Referencias

Errichello, Robert, Robert Budny, and Rainer Eckert. “Investigations of Bearing Failures Associated with White Etching Areas (WEAs) in Wind Turbine Gearboxes.” Tribology Transactions 56, no. 6 (2013): 1069–1076.

GNR, Analytical Instruments Group. “AreX Diffractometer: GNR Proposal for measuring Retained Austenite in the industrial domain and in laboratory.”

Herring, Daniel H., Atmosphere Heat Treatment. Volume I. Chicago: BNP Media, 2014.

Agradecimientos

Queremos agradecer a los siguientes contribuyentes por su aporte en el desarrollo de este artículo: Thomas Wingens, presidente y especialista en Heat Treat, WINGENS CONSULTANTS; Dennis Beauchesne, gerente general, ECM USA; Tim Moury, presidente & CEO, Marco DeGasperi, gerente técnico, Jeff Froetschel, vicepresidente y director financiero, Verichek Technical Services, Inc.; y Dan Herring, The Heat Treat Doctor®, The HERRING GROUP, Inc.

Find heat treating products and services when you search on Heat Treat Buyers Guide.Com

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Methods of Measuring Retained Austenite

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Most heat treaters recognize the importance of measuring retained austenite (RA), yet many opt not to perform these measurements due to time and/or cost constraints. This Technical Tuesday installment explains why performing RA measurements is necessary, the pros and cons of traditional measurement techniques, and the benefits of using more current and in plant technologies.

This informative piece was first released in Heat Treat Today’s March 2025 Aerospace Heat Treating print edition. To read the article in Spanish, click here.

Why Retained Austenite Percentage Matters

Before examining measurement methodologies, it is important to understand the fundamentals of retained austenite and why the percentage of retained austenite (RA%) matters.

Austenite that does not transform to martensite upon quenching is called retained austenite (RA). In simple terms, retained austenite (Figure 1) occurs when steel is not fully quenched to the martensite finish (Mf) temperature; that is, low enough to form 100% martensite. Because the Mf is below room temperature in most alloys containing more than 0.30% carbon, significant amounts of retained austenite may be present within the martensite at room temperature (Herring, Atmosphere Heat Treatment).

When it comes to RA%, there is often a delicate balance between its beneficial effects (an increase in the life of certain manufactured components) and its negative attributes (the creation of parts that are prone to cracking and failure). For this reason, it is crucial that heat treaters achieve the optimal RA% for the intended application.

For example, in the aeronautics and astronautics industries, RA levels are often specified to be under 8% and, for devices such as bearings and linear actuators, RA under 3% and as close to zero as possible is required. In other applications, however, such as large gearing for power generation, wind energy, and performance platforms, in the range of 15–30% or more RA has been found beneficial (Errichello et al., “Investigations of Bearing Failures”). Also, high RA% has been found beneficial for bearings that will be subjected to contaminated lubricants.

Figure 1. 12CrNi3 (similar to SAE/AISI 9310) bearing roller path surface microstructure consisting of tempered martensite with evidence of retained austenite (white areas)

Marco DeGasperi, technical manager at Verichek, weighed in on this, noting that for fuel injectors, small pieces in medical applications, and high-level, high-volume applications like wear plates in the mining industry, RA% is critical. He summarized with the statement, “When you’re applying pressure and motion to anything that’s fine-tuned … If you have ‘precision’ in your name, you probably want [an RA% measurement device].”

The very characteristics that give retained austenite many of its unique properties are those responsible for significant problems in service. We know that austenite is the normal phase of steel at high temperatures, but not at room temperature. Because retained austenite exists outside of its normal temperature range, it is metastable. This means that in service, factors such as temperature, stress, and even time will see it transform into untempered martensite. In addition, a volume change (increase) accompanies this transformation and induces a great deal of internal stress in a component, often manifesting itself as cracks, which leads to parts failing in the field.

RA% is also important not only because of its influence on dimensional stability but on mechanical properties such as yield strength, fatigue strength, toughness, and machinability (Herring, Atmosphere Heat Treatment). For example, looking in the automotive industry, DeGasperi gives an example of the consequences of having too high or too low RA%: “Let’s say pieces in a transmission or a transfer case; this is when gears start breaking or you get issued wide-end recalls. And then usually the supply chain all starts blaming the guy before them when nobody throughout the supply chain has actually tested the parts themselves.”

Alternatively, in some cases, finely dispersed RA helps the material resist the propagation of fatigue cracks and improves rolling contact fatigue stress, so balancing the amount of RA is important in many applications. Also, the correct RA% is essential for quality control, and proper control and accurate measurement of RA% in steel alloys is crucial to guaranteeing the quality and safety of finished components, as well as protecting the reputation and profitability of heat treaters and manufacturers.

RA Measurement Methods

Accurate RA measurements are critical to determine whether the correct balance of retained austenite and martensite exists within a given part. Several RA measurement methodologies are available to heat treaters, each having their own unique set of advantages and disadvantages. For heat treaters, understanding why it is crucial to measure the percentage of RA is only half the battle. Finding a cost-effective, fast, and accurate measurement method is the other half.

X-Ray Diffraction: The Best and Most Accurate Method

Figure 2a. An ArexD table-top unit from GNR

X-ray diffraction, which is used to identify and quantify phases in a material, is considered the most accurate method of RA measurement in steels as it can precisely determine RA levels down to the range of approximately 0.5–1% (GNR, “AreX Diffractometer,” 3). In X-ray diffraction, different crystalline phases have different diffraction patterns, allowing them to be identified and measured. In addition to phase analysis, X-ray diffraction can be used to analyze microstructural features such as texture, residual stress, and grain size.

Today, X-ray diffraction is a non-destructive, safe solution that can sample a much larger region than many other available methods and does not involve much sample preparation and analysis, making it a more efficient and effective solution. This is the option of choice for a company that needs to test RA with expected readings under 10%.

The current generation of X-ray diffractometers are tabletop sized, weighing about 25 lbs. With models under $100,000, they are also cost-effective when compared to traditional X-ray diffractometers ($200,000), which were sometimes problematic in the presence of additional phases and reflections due to grain size, carbides, or textures that could cause disturbances and variances in measurement. The new generation of X-ray equipment compensates for these obstacles via the use of multiple diffraction peaks to minimize the effects of preferred orientation and detect interference from carbides.

2b. An ArexD table-top unit from GNR

Modern X-ray diffraction machines can collect up to seven diffraction peaks (three for ferrite/martensite phase and four for austenite phase) and then determine the volume percent concentration of RA in the sample by comparing the intensities of the peaks and analyzing the peak ratios in accordance with the ASTM E975-22 (standard practice for X-ray determination of retained austenite in steel with near random crystallographic orientation).

The use of today’s X-ray diffraction equipment is not complicated. It can be measured in under three minutes by simply placing the sample in the machine and pressing the start button. These X-ray diffractometers measure various-sized samples and use intuitive software so the measurement can be performed quickly, accurately, and efficiently by any technician — with or without prior metallurgical or diffraction experience.

Optical Microscopy — A Time-Proven Method

RA can be measured metallographically with an optical microscope. An experienced metallurgist can usually determine RA% down to approximately 10–15% RA. For many applications, this is more than adequate and has the added benefit of characterizing the microstructure as well.

This method, which involves determining the austenite fraction using contrast from etching behavior or morphology, is low cost, however, it can be somewhat time consuming. Charts and diagrams in reference books are available to help determine the percentage of retained austenite by comparative methods. Optical microscopy is subjective as it is dependent upon the individual and their interpretation of the sample under the microscope.

Figure 3. Example of how RA% peaks are measured

Alternative Methods

Several other methods for measuring RA are available to heat treaters. The most common of these methods includes:

Magnetic Induction: Here, a sample is magnetized to saturation and the saturation polarization is measured. The difference between measured and theoretical saturation of the RA can then be calculated using this equation:

Magnetic induction is non-destructive and offers a higher, broader range than optical microscopy (1–30%). However, because it is a volume measurement, the instrument needs to be calibrated to the specific materials, heat treatment, and geometries, which is time consuming and highly dependent on the skill of the technician.

Electron Backscatter Diffraction (EBSD): Using this RA measurement method involves placing a sample in a Scanning Electron Microscope (SEM) to characterize the crystallographic structure as well as the microstructure. RA measurements using this technique are not particularly accurate and are reliant upon proper sample preparation. Additionally, it provides a very small measure volume and is a destructive test method.

Conclusion

Accurate measurement of the level of retained austenite allows both the design engineer and metallurgist to maximize its beneficial effects without suffering from its negative consequences. On the part of the heat treater this means taking into account the material chemistry and the heat treat process variables such as austenitizing temperature, quench rate, deep freeze or cryogenic treatments, and tempering temperatures.

References

Errichello, Robert, Robert Budny, and Rainer Eckert. “Investigations of Bearing Failures Associated with White Etching Areas (WEAs) in Wind Turbine Gearboxes.” Tribology Transactions 56, no. 6 (2013): 1069–1076.

GNR, Analytical Instruments Group. “AreX Diffractometer: GNR Proposal for measuring Retained Austenite in the industrial domain and in laboratory.”

Herring, Daniel H., Atmosphere Heat Treatment. Volume I. Chicago: BNP Media, 2014.

Acknowledgments

We’d like to thank the following contributors for the support of this article: Thomas Wingens, President & Heat Treat Specialist, WINGENS CONSULTANTS; Dennis Beauchesne, General Manager, ECM USA; Tim Moury, President & CEO, Marco DeGasperi, Technical Manager, Jeff Froetschel, VP & CFO, Verichek Technical Services, Inc.; and Dan Herring, The Heat Treat Doctor®, The HERRING GROUP, Inc.

This article is provided by the Heat Treat Today Editorial Team.

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Quench Oil Management: AMS2759 & CQI-9

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Given safety and performance concerns in the aerospace sector, it may be beneficial to consider quench testing that uses CQI-9 as well as AMS2759 since the automotive standard focuses on safety. Read on to understand the different approaches between these two standards in this Technical Tuesday installment, written by Michelle Bennett, quality assurance senior specialist, and Greg Steiger, senior account manager, both at Idemitsu Lubricants America.

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

In today’s world, there are many different quality systems available to heat treaters. Many of these, such as ISO, are quality management systems. These quality management systems are an important piece of running a successful business. However, to successfully run a heat treat business and compete in either the North American automotive market or the aerospace market, a heat treater must conform to either CQI-9 or AMS2759, or, in cases where a company processes both automotive and aerospace parts, both. This article will explain the requirements for both CQI-9 and AMS2759. It will also explain the differences between the two quality standards and any additional testing that could benefit a heat treater or how they operate their quench tank.

AIAG’s CQI-9

The Automotive Industry Action Group (AIAG) is a non-profit group of over 800 automotive OEMS, parts manufacturers, and service providers who oversee the requirements for CQI-9. The 4th edition is the most current edition of CQI-9. As an internal audit process, CQI-9 covers most of the heat treating process. Section 3.14 specifies the quench oil and water-soluble polymer requirements. An oil quenchant requires that the in-use oils be tested every six months and the testing must include water content, percent suspended solids, total acid number, viscosity, flash point, and cooling curve. The specification range and warning limits are based on the vendor’s requirements and recommendations. For water-based polymers, there are two tests required: concentration and quenchability. The standard does not specify a test for quenchability, however, it does make a few suggestions such as a cooling curve, viscosity, and titration.

For water-based polymers, there are two tests required: concentration and quenchability. The standard does not specify a test for quenchability, however, it does make a few suggestions such as a cooling curve, viscosity, and titration.

All the required testing of the quenchant is designed to achieve consistent metallurgy for safety reasons. Viscosity is monitored to look for oxidation or heat decomposition of the oil. Degradation can be in the form of oxidation, thermal breakdown, or the presence of various contaminants. Increased oil viscosity typically results in decreased heat transfer rates. A decrease in viscosity may indicate contamination. Some suspended solids are to be expected during the quenching process, but the majority of them should be filtered or centrifuged from the process. If the quantity of these contaminants becomes too high, then it can both affect the brightness of the parts, and the parts can get soft spots as the contaminants may not cool the parts at the same rate.

Water and flash point are both monitored for safety. If the flash point drops below the accepted range or the water content is above the acceptable range, these can cause fires during the operation. Water can also show issues with the equipment or the procedure such as leaking of anything that is water cooled, such as the outer door on a furnace. Acid value is monitored to degradation of the oil. As the oil breaks down and oxidizes, the acid value will increase. This can cause the maximum cooling rate to increase and can cause cracking or distortion on the parts. Carbon residue can be measured for two reasons. If the result is below the specification, it can show that the quench speed improver is being broken down or dragged out of the system. If the result is higher than the specification, it can show the formation of sludge, which will impact the brightness of the parts.

For water-based quenchants, the most common test items include pH, refractive index or brix, viscosity, and concentration calculation. Sometimes additional test items can be added, such as biological testing, to help determine and correct current issues.

Table 1. CQI-9 vs. AMS2759 quenchant requirements

SAE’s AMS2759

Just as AIAG is a non-profit business group responsible for CQI-9, SAE International is a non-profit organization responsible for AMS2759. The most recent revision of AMS2759 is Revision G. AMEC (the Aerospace Materials Engineering Committee) is responsible for maintaining this standard. Unlike CQI-9, AMS2759 requires a certificate of conformance for all shipments. Section 3.10.3 begins the requirements for quenchant testing and quenchant deliveries. Viscosity, flash point, and temperature at the maximum cooling rate must be reported on the certificate of compliance when dealing with mineral oil quenchants. For a polymer, the requirements are that the pH of the neat polymer and the neat viscosity of the polymer must both be reported on the certificate. Also required on the polymer certificate are the viscosity, pH, and the temperature at the maximum cooling rate for polymers at 20% dilution by weight.

Similarly to CQI-9, AMS requires that the in-use quenchants be tested biannually. This standard, however, only requires the cooling rate and temperature at max cooling rate be tested, as well as any additional tests the supplier recommends. The AMS2759 specification does not have set limitations on the cooling rate and temperature. Instead, the specification sets the allowed upper and lower deviations from the supplier’s standard for the maximum cooling rate and the temperature at the maximum cooling rate for both oils and water-soluble polymers. The supplier should have calculated the average max cooling rate and average temperature at max cooling rate using many different blend lots and multiple test runs. This average will not vary or change based on current production values or the values for the batch that the client is currently using (Table 1).

Although both standards require having the quenchant tested bi-yearly, most quenchant suppliers encourage their clients to submit their furnace samples for testing quarterly. This ensures that the medium is being monitored frequently, and if a sample is missed or late when sampling quarterly, then the client is still within compliance for the six month testing requirements.

However, because many of the test parameters in CQI-9 are run for safety reasons along with performance reasons, it is highly advised that aerospace heat treaters should run the full suite of CQI-9 testing along with the AMS2759 testing.

Taking a Quench Sample

There are many different quench methods and both standards allow for any of the following variations: ASTM D6200, ISO 9950, JIS K2242, ASTM D6482, or ASTM D6549. The type of testing that is going to be conducted will determine the size of sample that will be needed. For just this quench testing, the volume of sample needed ranges from 250 milliliters to 2 liters.

As always, when taking samples, it is important to be sure to get a good representative sample of the current quenchant being used in the process. The agitation needs to be running and collected in a clean and dry container. The sampling site should be the most convenient location to safely obtain a sample. It should also be the same location for every sample. The lid also needs to be put on before the oil cools too much because the container will draw in moisture and condensation as the oil cools if it is open to the atmosphere.

Conclusion

When examining the standards, there is one basic commonality: the need to run a complete cooling curve every six months. There is also a large difference in that AMS2759 does not require the full suite of testing that CQI-9 does. However, because many of the test parameters in CQI-9 are run for safety reasons along with performance reasons, it is highly advised that aerospace heat treaters should run the full suite of CQI-9 testing along with the AMS2759 testing. For automotive heat treaters, the maximum cooling rate and the temperature at maximum cooling rate is something that can be reported in the normal D6200 cooling curve test.

For manufacturers heat treating parts for aerospace, automotive, or both markets, we recommend quarterly quench samples at a minimum. The primary reason for more frequent testing is safety. Also, with the current labor shortage, heat treaters are busier than ever. If quench samples are routinely taken on a quarterly basis and are somehow missed and forgotten, there is still time to take another sample and remain in CQI-9 and AMS2759 compliance.

Remaining in compliance of these two important standards requires a lot of hard work from both the heat treater and the quenchant provider. Unless the quenchant supplier is working together in a true partnership, it will be very difficult to remain in compliance with the requirements for CQI-9 and AMS2759. But with routine monitoring, heat treaters can help to ensure quenchant and equipment have a longer life and achieve ever-tightening requirements from clients.

About The Authors:

Michelle Bennett
Quality Assurance Senior Specialist
Idemitsu Lubricants America

Michelle Bennett is the quality assurance senior specialist at Idemitsu Lubricants America, supervising the company’s I-LAS used oil analysis program. Over the past 12 years, she has worked in the quality control lab and the research and development department. Her bachelor’s degree is in Chemistry from Indiana University. Michelle is a recipient of Heat Treat Today’s 40 Under 40 Class of 2023 award.

Greg Steiger
Senior Account Manager
Idemitsu Lubricants America

Greg Steiger is the senior account manager at Idemitsu Lubricants America. Previous to this position, Steiger served in a variety of technical service, research and development, and sales and marketing roles for Chemtool Incorporated, Witco Chemical Company, Inc., D.A. Stuart Company, and Safety-Kleen, Inc. He obtained a BS in Chemistry from the University of Illinois at Chicago and recently earned a master’s degree in Materials Engineering at Auburn University. He is also a member of ASM International.

For more information: Contact Michelle Bennett at mbennett.8224@idemitsu.com or Greg Steiger at gsteiger.9910@idemitsu.com.

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The Future of Vacuum Oil Quenching

/ AEROSPACE HEAT TREAT TECHNICAL CONTENT, QUENCHING TECHNICAL CONTENT, VACUUM FURNACES TECHNICAL CONTENT

Despite years of research and development that resulted in several important technological innovations, the constraints of high-pressure gas quenching are ever more evident. In today’s Technical Tuesday, Robert Hill, FASM president of Solar Atmospheres of Western PA, addresses the creation of a new, robust style of vacuum oil quench furnace. The results challenge the schematics in how the next generation of oil quench furnaces should be designed, built, and operated.

This informative piece was first released in Heat Treat Today’s November 2024 Vacuum print edition.

Introduction

After decades of research and development that resulted in several important technological innovations, the constraints of high-pressure gas quenching are ever more evident. Gas cooling runs into efficacy issues when compared to liquid quenchant cooling, chiefly for heavier cross sections. This stays true even when using specialized inert gas blends and heightened gas pressures.

Additionally, it is undeniable that stringent liquid quench Aerospace Material Specifications (AMS) standards for certain aerospace alloy steels will never change. In fact, many industry standards (e.g., SAE/AMS and U.S. defense standards) and client specifications often mandate oil quenching of alloys or component parts.

To meet the demand for an effective, sustainable liquid quench solution, Solar Manufacturing with Solar Atmospheres engineers worked through the tumultuous period of the pandemic to create a new, robust style of vacuum oil quench furnace. Their work culminated in a vacuum oil quench furnace with a 36″ x 36″ x 48″ hot zone that operates up to 2000°F and can accommodate a weight capacity of 2000 lbs. With high uptime reliability and excellent metallurgical results, the NEO™ represents a paradigm shift in how the next generation of oil quench furnaces should be designed, built, and operated.

Figure 1. No decarburization, carburization, or surface contamination when tested in accordance with AMS2759/2 Source: Solar Atmospheres of Western PA

Rigorous Design for Metallurgical Excellence

The next generation of oil quench furnaces heralds an era of metallurgical excellence. This is made apparent across three key measures: control over surface contamination, prevention of parts cracking, and flexible processing of dissimilar materials.

No Surface Contamination

Figure 2. Loading in the NEO furnace
Source: Solar Atmospheres of Western PA

By implementing a vacuum design to the oil quench furnace, the research team avoided issues faced by traditional atmosphere oil quench furnaces, such as surface contamination and intergranular oxidation/intergranular attack (IGO/IGA). Additionally, they meticulously addressed design concerns regarding oil backstreaming in the new multichambered vacuum system. After two years of usage, the hot zone has remained pristine and oil-free.

By effectively removing the possibility of any surface contamination, both IGO and decarburized or carburized surfaces on oil quenched components are eliminated. These critical metallurgical features are unattainable in traditional gas-fired Endothermic batch furnace equipment.

Precision Prevents Part Cracking

To eliminate the potential of part cracking, quench oil temperatures should be able to be maintained between 140°F to 180°F ±5°F, which enhances consistent and repeatable metallurgical results. Furthermore, having the furnace designed so that quench oil recirculates within a closed loop oil to air cooling system keeps water contamination from infiltrating the oil.

No Carbon Content Matching

The next generation of vacuum oil quench furnaces should also have highly controllable atmospheres, devoid of oxygen, which will remove the need to mechanism, which has demonstrated flawless performance for over two years.

Additionally, it is imperative that these furnaces be capable of using more conventional quench oil. A good quench needs excellent vapor pressure, powerful enough to allow the oil to vaporize. Furnaces can be designed with this in mind, allowing operators to save costs by using more conventional quench oils. For example, after rigorous laboratory experimentation into the vaporization of various quench oils at different pressures and temperatures, it was decided to purchase 3000 gallons of Houghton G quench oil, versus the “vacuum only” quench oils that are currently on the market today.

Figure 3. A display of a variety of parts which can be processed in the same run
Source: Solar Atmospheres of Western PA

The next generation of oil quench furnaces should also finally provide metallurgical and quality engineers the ability to thermocouple the oil quenched parts in accordance with AMS2750 Rev H standards. Being able to monitor part temperature with up to twelve (12) data points, as defined by the latest AMS2750 revision, ensures thorough and precise thermocouple monitoring, bolstering control and repeatability.

Lastly, in a hermetically sealed furnace, another layer of control should be established through installing an internal camera. With “eyes” into the furnace, the operator will be able to watch the load transfer in real time from a control panel.

Figure 4a and 4b. Thermocoupled parts Source: Solar Atmospheres of Western PA

These operational attributes are on full display in the example of an automated austenitized cycle: At the completion of the cycle, the specially-designed transfer mechanism delivers precisely heated parts from the hot zone to the 3000-gallon oil quench chamber consistently within 20 seconds — all without the expulsion of flames and the discharge of smoke.

Oil flames and smoke are no longer acceptable realities in heat treatment operations. Unfortunately, the heat treating industry has been misled in the belief that a catastrophic disaster will never happen to them. There have been multiple “total losses,” mostly due to oil quench fires and explosions. Recently, it is well known that if an insurance adjuster sights a flame or smoke within a plant, they are reluctant or may even refuse to write the policy.

Vacuum furnaces offer a safe, contained alternative to the harmful open emissions and dangerous working conditions. For operations where the safety and the well being of the workforce are paramount, vacuum furnaces eliminate the risks associated with open flame exposure, explosivity, and skin burns.

Yet the next generation of vacuum oil quench furnaces should also open at both ends at the end of a cycle to expose it to atmosphere. Full air exchange mitigates the potential hazards of confined spaces.

Figure 5. Top view showing innovative design features for the next generation of vacuum oil quench furnaces
Source: Solar Atmospheres of Western PA

Meeting Environmental Demands

With ever more stringent environmental regulations, the next generation of vacuum oil quench furnaces will play a pivotal role in reducing the carbon footprint of the heat treating industry. It has been estimated that 80% of fuel used for heat treatment could be replaced by electricity, thus drastically reducing CO2 emissions: “When you burn something that contains carbon, you get carbon dioxide that you either must take care of or release into the atmosphere. With electric heating, you do not have any exhaust.”

The second column in the chart on page 30 addresses the multiple environmental concerns associated with traditional batch IQ gas-fired oil quenching furnaces. The third column outlines the advantages of the design for the next generation of oil quench furnaces, which embraces electric heating as a sustainable alternative to fossil fuels. As sustainability pressures continue to mount, governments, clients, and primes alike will continue to flow down requirements on how heat treaters plan to reduce their carbon footprints.

Figure 6. Safety hazards in operating atmosphere furnaces
Source: The Monty

Conclusion

As the demands for metallurgical precision, safety, and environmental sustainability continue to mount, Solar’s new vacuum oil quench furnace emerges as a representative of the next generation of vacuum oil quenching technology. Characterized by unparalleled efficiency, precision, and sustainability, such furnaces will continue to lead the industry toward a future defined by cleanliness, safety, and environmental stewardship.

Table 1. Data from the AICHELIN Group
Source: Solar Atmospheres of Western PA

References

Kanthal, “Heat Treatment CO2 Emissions cut by 50 percent by using electricity” (April 2019), https://www.kanthal.com/en/knowledge-hub/inspiring-stories/heat-treatment-co2-emissions-cut-by-50-percent-by-using-electricity/.

Aichelin Group, “CO2 Footprints and the Heat Treat Industry,” The Monty (January 2024).

About the Author:

Robert Hill, FASM
President
Solar Atmospheres of Western PA
Solar Atmospheres of Western PA

Robert Hill, FASM, began his career with Solar Atmospheres in 1995 at the headquarters plant in Souderton, PA. In 2000, Hill was assigned the responsibility of starting the second plant in Hermitage, PA, 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.

For more information: Contact Robert at bob@solaratm.com. 

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Ask the Heat Treat Doctor®: How Do Parts Fail?

/ AEROSPACE HEAT TREAT TECHNICAL CONTENT, ATMOSPHERE AIR FURNACES TECHNICAL CONTENT, Manufacturing Heat Treat Technical Content

The Heat Treat Doctor® has returned to offer 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.

Product failures (Figure 1) can often be traced to deficiencies in design, materials, manufacturing, quality, maintenance, service-related factors, and human error to name a few. Examples of failures include misalignment, buckling, excessive distortion, cracking, fracture, creep, fatigue, shock, wear, corrosion, and literally hundreds of other mechanisms. Let’s learn more. 

Figure 1. Image of damage to left fuselage and engine; fire damage to nacelle.
Source: National Transportation Safety Board
Figure 2.: Model of material science depicting— key interactions and /interrelationships
Source: The HERRING GROUP, Inc.

Whatever the source, it is important to recognize that it is next to impossible to separate the product from the process.  Performance, design (properties and material), metallurgy (microstructure), heat treatment (process and equipment), and maintenance are all interconnected (Figure 2).  

When considering ways to prevent failures from occurring, one must determine the factors involved and whether they acted alone or in combination with one another. Ask questions such as, “Which of the various failure modes were the most important contributors?” and “Was the design robust enough?” and “Were the safety factors properly chosen to meet the application rigors imposed in service?” Having a solid engineering design coupled with understanding the application, loading, and design requirements is key to avoiding failures. If failures do happen, we must know what contributed to them.  

Let’s review a few of the more common failure modes. 

Fracture Types on a Macroscopic Scale  

Applied loads may be unidirectional or multi-directional in nature and occur singularly or in combination. The result is a macroscopic stress state comprised of normal stress (perpendicular to the surface) and/or shear stress (parallel to the surface). In combination with the other load conditions, the result is one of four primary modes of fracture: dimpled rupture (aka microvoid coalescence), cleavage, decohesive rupture, and fatigue. 

Virtually all engineering metals are polycrystalline. As a result, the two basic modes of deformation/fracture (under single loading) are shear and cleavage (Table 1). The shear mechanism, which occurs by sliding along specific crystallographic planes, is the basis for the macroscopic modes of elastic and plastic deformation. The cleavage mechanism occurs very suddenly via a splitting action of the planes with very little deformation involved. Both of these micro mechanisms primarily result in transgranular (through the grains) fracture. 

Fracture Types — Ductile and Brittle  

Numerous factors influence whether a fracture will behave in a ductile or brittle manner (Table 2). In ductile materials, plastic deformation occurs when the shear stress exceeds the shear strength before another mode of fracture can occur, with necking typically observed before final fracture. Brittle fractures occur suddenly and exhibit very little, if any, deformation before final fracture. (The following is based on information found in Wulpi, 1985.)

Ductile fractures typically have the following characteristics: 

  • Considerable plastic or permanent deformation in the failure region 
  • Dull and fibrous fracture appearance 

Brittle fractures typically have the following characteristics:

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  • Lack of plastic or permanent deformation in the region of the fracture 
  • Principal stress (or tensile stress) is perpendicular to the surface of the brittle fracture 
  • Characteristic markings on the fracture surface pointing back to where the fracture originated  

When examined under a scanning electron microscope, fracture surfaces seldom exhibit entirely dimpled rupture (i.e. ductile fracture) or entirely cleavage (i.e. brittle fracture), although one or the other may be more prevalent. Other fracture modes include intergranular fractures, combination (quasi-cleavage) fractures and fatigue fractures. 

Fracture Types — Wear 

Wear (Table 3) is a type of surface destruction that involves the removal of material from the surface of a component part under some form of contact produced by a form of mechanical action. Wear and corrosion are closely linked, and it is important not only to evaluate the failure but to take into consideration design and environment and have a good understanding of the service history of a component. 

Fracture Types — Corrosion 

Corrosion is the destruction of a component by the actions of chemical or electrochemical reactions with the service environment. The major types of corrosion include galvanic action, uniform corrosion, crevice corrosion, stress-corrosion cracking, and corrosion fatigue. The mechanisms and effects created by each of these are well documented in the literature, as in Fontana and Greene’s Corrosion Engineering (1985) and Uhlig’s Corrosion and Corrosion Control (1985). It is critical to understand that the effects of corrosion are present to some degree in every failure analysis, which is one of the reasons why protecting fracture surfaces is so critical when sending parts for failure analysis. 

Table 1. Differences between shear and cleavage fracture (Data referenced from page 23 of Wulpi, see References.)
Source: The HERRING GROUP, Inc.
Table 2. Typical characteristics of ductile and brittle fractures
Source: The HERRING GROUP, Inc.
Table 3. General categories of wear
Source: The HERRING GROUP, Inc.

Final Thoughts

To avoid failures or their reoccurrence, it is important to document each step in the design and manufacture process (including heat treatment). In addition, careful documentation of failures if/when they occur is of critical importance as is assembling a team of individuals from different disciplines to perform a comprehensive investigation. This includes a thorough failure analysis to assist in determining the root cause (there is only one) and to avoid it from happening in the future. 

References

Airline Safety. www.AirlineSafety.com. Accessed September 2024.

Fontana, M. G., and N. D. Greene. Corrosion Engineering, 3e. McGraw-Hill Book Company, 1985.

Herring, Daniel H. Atmosphere Heat Treatment, Volume Nos. 1 & 2. BNP Media, 2014/2015.

Lawn, B.R. and T. R. Wilshaw. Fracture of Brittle Solids. Cambridge University Press, 1975.

Shipley, R. J. and W. T. Becker (Eds.). ASM Handbook, Volume 11: Failure Analysis and Prevention. ASM International, 2002.

Uhlig, H. H. Corrosion and Corrosion Control. John Wiley & Sons, 1963. 

Wulpi, Donald J. Understanding How Components Fail. ASM International, 1985.

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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Streamline Essential Nadcap Certifications

/ AEROSPACE HEAT TREAT TECHNICAL CONTENT, MANUFACTURING HEAT TREAT, OP-ED

Nadcap certifications are integral to aerospace heat treating. Maintaining compliance, however, can be a headache. Learn how a new technology is streamlining Nadcap certifications.

This article by Chantel Soumis was originally published in Heat Treat Today’s March 2024 Aerospace Heat Treat print edition.

Challenges to Capture Nadcap Certifications

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The Nadcap certification (National Aerospace and Defense Contractors Accreditation Program) plays a critical role in maintaining the integrity of heat treating processes, especially in the aerospace and defense industries. Recognized globally, the certification sets rigorous standards for heat treatment facilities, ensuring that heat treating processes produce parts and materials with the necessary strength, durability, and reliability.

The certification addresses the data that needs to be documented concerning all aspects of the heat treat processing, such as temperature control, process documentation, and quality management. A survey from the Performance Review Institute (PRI) indicates that 80% of aerospace and defense companies consider Nadcap accreditation as a requirement when selecting suppliers, and 90% of aerospace and defense prime contractors would disqualify a supplier without Nadcap accreditation. And when such a strict standard is implemented and then subject to regular audits, a 40% reduction in nonconformance costs are likely, as was reported by companies in the aerospace and defense sector in a study by the National Center for Manufacturing Sciences (NCMS).

While compliance with Nadcap and other heat treat certifications demonstrates a commitment to quality and opens doors to lucrative contracts with aerospace, defense, and other precision industries, actually capturing the data can be tedious. The effort and cost of employing disconnected systems — capturing measured data from system A, making the certification documents in system B, and then emailing the certification results to clients from system C — can be cut by synthesizing these actions into one system.

Digitizing Certification Management for Complete Compliance Control

Many organizations facilitate the certification process via digital means. This may be through the use of digital quality management systems (QMS) or enterprise resource planning (ERP) software that includes modules designed for certification management. These tools help automate record keeping, provide alerts for upcoming certification renewals, and streamline the overall certification tracking process, ensuring that heat treating operations remain compliant and efficient.

Nadcap Scanner tracking a process via QR code

But more should be done.

Veterans Metal, a metal finishing plant in Clearwater, Florida, was driving manual processes: everything was written down and data was being entered into spreadsheets for tracking purposes. Like many heat treaters, each step the company took to process a part required manual intervention to write down 20+ line items of information and then incorporate the associated data entry into spreadsheets.

The company was looking to modernize their plant.

After careful evaluation of Veterans Metal’s processes and needs, Steelhead Technologies developed and deployed the Steelhead Certification Scanner (or Nadcap Scanner) line that includes a handheld scanner and a system of QR codes to facilitate an easier user experience, including an interface that allows for swift operator proficiency, typically within minutes. This digital interface allows users to measure data, create certifications, and email this from the one system.

Smart Scanning in Action

The metal processing company received a 15-minute walk-through of the Nadcap Scanner, how to process parts, and where to find the data within the system. Using the handheld device, operators scanned QR codes (specifically created by Steelhead Technologies) that were placed on processing stations. As parts were moved from one process station to the next manually, a user would scan the accompanying QR code on the next current station, locking in data from the previous process and automatically reflecting that the next step was in process.

When operators scanned a process station, the device showed the remaining time in the process and displayed all parts being processed, custom instructions, and key data collection, such as oven temperature. This timer automatically starts when a process station QR code is scanned, gives a one minute warning when the process is nearing completion, and stops automatically when the next process station QR code is scanned.

Chet Halonen, a plant optimization expert for Steelhead Technologies, presented the “Powered by Steelhead” certification to the Veterans Metal team.

With the intuitive layout and guided steps, operators were easily able to navigate the accreditation process, significantly reducing time spent on extensive training. More importantly, the Nadcap Scanner line eliminated handwritten data entry, margin of error, and additional time needed to develop certifications since the scanner automatically generates them from the data and sends them to clients. The scanner has since been adopted by many other Nadcap-compliant operations across the United States.

Take Nadcap Digital

Achieving Nadcap accreditation is crucial for showcasing a commitment to quality, aligning with industry benchmarks, and accessing lucrative business opportunities. With the advent of digitized solutions like the Nadcap Scanner implemented within a comprehensive manufacturing ERP, companies will streamline the accreditation process, enhance operational efficiency, and bolster compliance with a system that’s “literally just button clicking,” as one manufacturer observed.

Embracing innovative tools not only saves time and resources, but also strengthens market positioning and client relationships. By merging the prestige of Nadcap accreditation with digital advancements, heat treaters can elevate their operations to reach new heights of excellence.

About the Author

Chantel Soumis, Head of Marketing, Steelhead Technologies

Chantel Soumis is serving as the head of Marketing at Steelhead Technologies. With a robust background in manufacturing technology and strategic partnerships, she leverages over 15 years of experience to shape the company’s marketing landscape.

For more information: Contact Chantel at chantel@gosteelhead.com.

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Heat Treating AM Components to Infinity and Beyond

/ AEROSPACE HEAT TREAT, AEROSPACE HEAT TREAT TECHNICAL CONTENT, MANUFACTURING HEAT TREAT, MANUFACTURING HEAT TREAT TECH, SINTERING POWDER/METAL TECHNICAL CONTENT

The amazing materials that are produced through additive manufacturing (AM) and 3D machining often require post-processing heat treatments before these become final components that launch into space. What are the trends of AM/3D outside our planet, and what technical resources are available to you as you make one step into this field? This original content piece from the Heat Treat Today editors will help you understand where technology stands in 2024.

Why Does AM/3D Go to Space?

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A broad spectrum of industries have found the appeal of additively manufactured parts, industries ranging from mining to medical and automotive to space. Much of this has to do with complexity of components that new engineering techniques require, the desire to save on material costs, and the ability to condense lead time. For some, additive manufacturing is becoming essential to the space industry; as Tobias Brune, head of the Business Unit Additive Manufacturing at TRUMPF, has commented, “With our 3D printing technology, we are driving the commercialization of the space-travel industry. If you want to be successful in the space-travel industry today, you have to use additive manufacturing.”

When should you expect this transition? Now.

In January of this year (2024), the first metal 3D printer for space was launched to the Columbus module of the International Space Station (ISS). This is a very active, integrated sense of seeing AM in the aerospace industry, and test runs with this equipment will ensue.

Flight model of 3D Metal Printer Launched on NG-20
Source: ESA

The Exploration Company in Europe plans to use 3D printers from TRUMPF (laser specialist) to print core components in engines for spacecrafts. The intent: missions in Earth’s orbit and to the moon.

Heat Treat & thermal Processing Requirements of Post-Processing AM

If you are going to get involved in AM, it is essential to have the right equipment. One of the most talked about equipment is hot isostatic pressing (HIP) technology. Often, heat treat operations use HIP equipment for post-process heat treating in order to get the solid part they desire. For the most part, commercial heat treaters have positioned themselves to handle the R&D required to navigate the terrain of overcoming processing challenges of new/complex parts and creating standardizations. However, private R&D facilities and departments are also building out their capabilities to handle AM in HIP.

However, so also have vacuum furnaces been a key leader in heat treating AM components. Here, commercial heat treaters have also made moves to expand their equipment/process offerings to accommodate AM parts.

So also do atmosphere considerations need to be considered, with gasses like H2 competing trying to capture the limelight.

Continue the Exploration: AM/3D Articles for Space

Looking for an introduction to the AM/3D topic for heat treaters? Begin with this article by Animesh Bose, an engineering pioneer: “The Role Of Heat Treat in Binder Jetting AM for Metals.” The article uncovers the history of one of the most important types of AM/3D manufacturing — binder jetting AM.

Then, take a step over for an industry focus on what “heat treatments for space” look like. Mike Grande eloquently summarized the current processes needed in space in this editorial from the March 2024 Aerospace print edition. Read “The Role of Heat Treatment in Space Exploration” in the digital edition of the magazine.

In-house or commercial? This article presents critical considerations of space components — with a particular emphasis on the importance of AM/3D — when considering how to grow your processing expertise and capabilities. Several examples from the frontlines of R&D are presented by Noel Brady in his article. Read the editorial, “Thermal Processing for Space and Additive Manufacturing,” for excellent illustrations.

Finally, hone in on the topic with a case study about developments in HIP technology for space component post-processing. This article begins with context confronting issues of structural integrity, especially of complex space components, with HIP. Andrew Cassese gets to the case study towards the end of his article, “High Pressure Prepares Parts for Space.”

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High Pressure Prepares Parts for Space

/ AEROSPACE HEAT TREAT, AEROSPACE HEAT TREAT TECHNICAL CONTENT, FEATURED NEWS, HIPING TECHNICAL CONTENT

Dive into the role and benefits of HIP and HPHT™ in the space industry, highlighting how these key processes are shaping the future of space applications.

This Technical Tuesday article by Andrew Cassese, applications engineer, Quintus Technologies was originally published in Heat Treat Today’s March/April 2024 Aerospace print edition.

The realm of space exploration and technology is rapidly evolving, pushing the boundaries of what’s possible in engineering and material science. Among the key players in this revolutionary change are hot isostatic pressing (HIP) and High Pressure Heat Treatment™ (HPHT™). These processes have become indispensable in manufacturing components that can withstand the harsh conditions of space. In this demanding environment, the longevity and reliability of components are paramount.

Reducing Risk

Space missions have put increasing focus on the need to minimize risk and improve mission safety. Some well-documented, safety-related events include:

  • Outer space
    • Soyuz 11 decompression in 1971
  • Earth’s atmosphere
    • Soyuz 1 parachute failure in 1967
    • X-15 controls failure in 1967
    • Space Shuttle Challenger launch
      booster failure in 1986
    • Space Shuttle Columbia re-entry
      disaster in 2003

Structural integrity is therefore in focus for every single component involved in space missions, with exacting demands on quality and function. Material failure is not an option, and therefore component qualification is one of the main areas of focus. Predictable properties that are reliable and with minimal variation are critical for mission safety. Hot isostatic pressing helps to guarantee this by reducing the spread and variation in mechanical properties.1 It works to do this by using high temperatures and pressures to close internal defects in mission critical parts after casting or additive manufacturing. This increases the density of components and gives them a more anisotropic microstructure which in turn results in more consistent mechanical properties.2

What Properties Are Most Important

The harsh environment of space demands components with exceptional properties. They must withstand extreme temperatures, resist radiation, endure vacuum pressures, and cope with mechanical stress from vibrations and accelerations. HIP processing plays a pivotal role in this, enhancing material properties to meet these challenges. Space manufacturers also must think about thermal expansion/contraction due to temperature variations, compressive stresses, irradiation, and space debris. All of these can affect mission success and can ultimately prevent loss of life, see Figure 1.

Figure 1. Challenges that space-bound materials must endure

Through HIP, components gain increased fatigue life, improved ductility, and enhanced fracture toughness, which are crucial for surviving in space.

Common Materials and HIP Processing Requirements

Materials commonly processed by HIP for space applications include titanium, aluminum alloys, nickel-based superalloys, refractory alloys, shape memory alloys, and ceramics. High-strength aluminum and titanium alloys are used due to their high strength to weight ratio which is key for space missions to conserve fuel efficiency, increase payload capacity, and improve maneuverability.3 Nickel-based superalloys are used in exhaust valves and turbine rotors due to their exceptional creep resistance properties at high temperatures. Refractory alloys like Nb-C103 and TZM are used in high-performance rocket nozzles because of their high melting point and excellent strength at high temperatures. Newer shape memory alloys developed by NASA can recuperate their original shape when heating above specific critical temperatures, and their applications are expanding beyond just actuators.4

As new alloys and materials are developed in the space industry, certifications and standards are necessary for their adoption. HIP effectively eliminates porosity in these materials, ensuring structural integrity and performance under the extreme conditions of space. This means HIP recipes need to be developed and optimized for materials to be tested with their greatest potential in mind.

Challenges in Processing Space Components

Processing components for space via HIP is not without its challenges. Th e extreme conditions required for HIP, including high temperatures and pressures, demand robust and sophisticated equipment. Quintus Technologies applications centers utilize a graphite furnace capable of heating to 3632°F (2000°C), while maintaining pressures of 30,000 psi (200 MPa). The process requires precise control to ensure uniformity of properties across the component. Specifically, the graphite uniform rapid cooling© (URC©) furnace can maintain temperature uniformity while controlling to a specified cooling rate.

Another challenge with processing space components in HIP can be oxidation of parts in the HIP furnace atmosphere. Niobium, for example, can suffer from substantial oxidation at elevated temperatures. In practice, tantalum foil is typically used to wrap the niobium components during HIP and to prevent oxidation from any residual moisture in the argon atmosphere. New products, like the Quintus Purus©, can reduce the amount of oxidation seen on parts aft er HIP while saving valuable time and resources by not having to wrap parts with getter materials like stainless steel, titanium, or tantalum.

Ongoing Research and Unknowns

Collaborations with universities and national labs on projects at low TRLs will help set the foundation for HIP in the space industry. Quintus Technologies, through its application centers, is actively engaged in research to further enhance the capabilities of HIP for space applications. Optimizing the HIP process to reduce costs and improve efficiency through HPHT is one area where the company has already found success, see Figures 2 and 3.

Figure 2. Typical thermal processes for additively manufactured parts
Figure 3. High pressure heat treatment with solution heat treatment (SHT) process for the same parts, using an integrated heat treatment approach

The HPHT process can combine stress relief, solution annealing, HIP, and aging into one cycle. Aft er a ramp up in pressure and temperature, the part is held for a specified amount of time before being rapidly cooled in the URC furnace. Aft er this, the temperature of the machine can be brought up to the aging temperature of the material for the completion of an in situ heat treatment.

A Space Case – Launcher Engine-2 Rocket Engine

Table 1. CuCrZr vs. GRCop-42: A Comparison

One application of this is on the Launcher Engine-2 (E-2) rocket engine.

Quintus Technologies, EOS Group, and Launcher worked together to develop a tailored HPHT cycle for Launcher’s 3D printed E-2, first vetted out in an applications center at small scale. The powder alloy in question, CuCrZr, was developed by EOS and printed on an AMCM M4K machine. EOS compared CuCrZr to the NASA alloy of GRCop-42 and found that the CuCrZr alloy was a more economically viable solution for thermal applications with lower strength requirements, see Table 1. The rapid cooling at 200°C/min in the QIH 122 URC furnace at Aalberts surface technologies allowed the team to HIP and solution heat treat the CuCrZr combustion chamber in a single step. The aging treatment was also performed in the QIH 122 directly aft er the solution.5

In October 2020, a full-scale test firing of the E-2 injector and combustion chamber was conducted at the Launcher NASA Stennis Space Center test stand. On April 21, 2022, Launcher’s E-2 liquid rocket engine was able to demonstrate full thrust. Continued tests from Launcher have been successful with performance boost testing
and the first fully integrated engine was ready for shipping on October 12, 2023.6

Figure 4. Aalberts QIH-122 MURC in Greenville, SC (Source: Aalberts Surface Technologies)

Conclusion

As humanity reaches further into the cosmos, the role of HIP and HPHT in manufacturing space-bound components becomes increasingly significant. These processes not only enhance the essential properties of materials for space applications but also address the unique challenges of manufacturing for an environment as hostile as space. With ongoing research and development, HIP and HPHT continue to evolve, promising to unlock new possibilities in space exploration and technology, and their contribution will ensure the success of space missions, safeguarding the lives of those who venture into the final frontier.

Figure 5. Test firing of the High Pressure Heat Treated Launcher Engine 2 produced using additive manufacturing

References

[1] Dominik Ahlers and Thomas Tröster, “Performance Parameters and HIP Routes for Additively Manufactured Titanium Alloy Ti6Al4V. EuroPM,” 2019. https://www.semanticscholar.org/paper/Performance-Parameters-and-HIP-Routes-fortitanium-
Ahlers-Tr%C3%B6ster/faeb46e6eb8ef3e30bc00b91cd1bd8a7c0619200.
[2] Jake T. Benzing et al., “Enhanced strength of additively manufactured Inconel 718 by means of a simplified heat treatment strategy,” Journal of Materials Processing Technology 322, (December 2023). https://www.sciencedirect.com/science/article/abs/pii/S0924013623003424?via%3Dihub.
[3] “Engineering Materials for Space Building Stronger Lighter Structures,” Utilities One, last modified November 2023. https://utilitiesone.com/engineering-materials-for-space-building-stronger-lighter-structures.
[4] Girolamo Costanza and Maria Elisa Tata, “Shape Memory Alloys for Aerospace, Recent Developments, and New Applications: A Short Review,” Materials (Basel) 13, no. 8 (April 2020): 1856. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7216214/.
[5] Mahemaa Rajasekar, “Processing Copper Alloys with Powder Bed Fusion,” LinkedIn, last modified November 2022. https://www.linkedin.com/pulse/processing-copper-alloys-dmls-technology-mahemaarajasekaran/.
[6] LAUNCHER (@launcher), “The first fully integrated E-2 engine is ready for shipping to @NASAStennis for our upcoming full engine test campaign later this year. E-2 is a 22,000 lb. (10 ft) thrust LOX/Kerosene,” X post, October 12, 2023. https://twitter.com/launcher/status/1712636548997607752.

About the Author

Andrew Cassese, Applications Engineer, Quintus
Technologies

Andrew Cassese is an applications engineer at Quintus Technologies. He has a bachelor’s degree in welding engineering from The Ohio State University.

For more information: Read J Shipley, “Hot Isostatic Pressing in Space – Essential Technology to Ensure Mission Safety,” 2020. Contact Andrew at andrew.cassese@quintusteam.com.

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Thermal Processing for Space and Additive Manufacturing

/ AEROSPACE HEAT TREAT, AEROSPACE HEAT TREAT TECHNICAL CONTENT, FEATURED NEWS, HIPING TECHNICAL CONTENT, SINTERING POWDER/METAL TECHNICAL CONTENT

The race to space is in full swing with public and private sector companies staking their claim in this new frontier. And breakthroughs in technology and materials offer the potential to propel humanity to unprecedented distances. Success hinges not only on the ability to discover novel solutions but also on the capacity to prepare those solutions for efficient, large-scale production.

This Technical Tuesday article by Noel Brady of Paulo was originally published in Heat Treat Today’s March/April 2024 Aerospace print edition.

Space Today: Making Life on Earth Better, Safer, and More Connected

Noel Brady, Metallurgical Engineer, Paulo
Source: Paulo

According to NASA, 95% of space missions in the next decade will stay in low Earth orbit (LEO) and geostationary orbit (GEO). Th at means the first wave of commercial activity in space will be largely focused on making life on Earth better.

Several worldwide broadband satellites are already in orbit, offering more consistent, reliable internet signals around the globe. Defense campaigns are using advanced satellite machine learning to improve asteroid and missile detection, along with revolutionary laser technology that has made intersatellite communication possible for the first time — and the travel of information faster. And to help make
life in space safe and successful, NASA is developing a scalable network of public GPS receivers for easy, short-range space navigation and tourism.

All this to say, parts are being developed for a wide range of applications, a huge portion of which are being additively manufactured.

Thermal Processing Standards Necessary for AM Adoption

However promising additive manufacturing is for space, the adoption of AM has still been limited due to the lack of standards for proprietary material and 3D printing applications. Many thermal processing experts are joining research institutions and OEMs in the drive to bring AM into mainstream manufacturing with new industry standards and production-ready solutions that help achieve ROI.

The R&D process for discovering these standards can be lengthy and expensive because it requires trial and error. A prototype or small run of parts must be manufactured, then heat treated, and tested for the desired properties. If a test part’s yield strength is not where it should be, for example, then the heat treating recipe is adjusted, perhaps by lowering the temperature and increasing the pressure, and can be tested again on a new batch of parts.

Coach vs. Custom Cycles

In heat treating, there are two different types of cycles, and it’s important to know the difference when you’re working with any commercial heat treater. Coach cycles tend to be more economical because these are shared cycles — existing recipes that are in high demand and run on a regular schedule — with the potential to have multiple clients’ parts in the furnace at once. For example, a heat treater may have a standard titanium coach cycle they run once a day. See Table A for several coach cycles run at Paulo.

Table A. Example of Coach Cycles for Space Alloys

Coach cycles use recipes that were designed for cast parts and have been around since before additive was a viable form of manufacturing. While it’s true that cast parts and AM parts have similarities, such as their high porosity, it doesn’t mean that the recipes are optimal for preparing today’s parts for heavy space applications. That’s where custom cycles come into play.

Custom cycles are ideal for new or proprietary materials that don’t yet have recipes defined or that are not commonly heat treated enough to run on a regular schedule. The distinction between the two is important because not all heat treaters are equipped to run both types. While you may be able to find a coach recipe that gets you close to where you need to be, it certainly may not be optimal, especially for parts that will have a heavy life of service.

Heat treaters with flexibility of custom and coach cycles, along with full-cycle data reporting, offer a high level of control that is vital for helping the industry progress and scale for production. This is also a big reason why some in-house heat treating operations may choose to outsource some of their work: first collaborating with experienced commercial heat treaters to prove the specification for a new part with custom cycles before scaling for production.

Common Cycle Adjustments for AM

There are five primary parameters that can be adjusted in the heat treating of AM parts to achieve the desired results: temperature, pressure, time, cooling rate, and heating rate. For AM parts, adjustments to the temperature and pressure are a go-to for achieving parts with higher yield strength. For example, running a cycle 50°F cooler, but at 5 ksi higher pressure may yield better results.

There may also be certain heating ramp rates and intermediate holds before parts get to the max temperature, to allow for consistent heating and enhance the material properties. The same goes for the cooling process: controlling the rate at which a part cools with specific holding times and intermediate quenches.

Hot Isostatic Pressing, Space, and Additive Manufacturing

Hot isostatic pressing (HIP) combines high temperature and pressure to improve a part’s mechanical properties and performance at extreme temperatures. The sealed HIP vessel provides uniform pressure to bring parts to 100% theoretical density with minimal distortion. The high level of control and uniformity has made HIP the gold standard for AM parts for space.

Similar to cast parts, 3D-printed materials tend to have porous microstructures that can compromise part performance. HIP is the only process that’s able to eliminate these pores without compromising the complex geometries and near-net dimensions that are achieved in the printing process.

Benefits of HIP for space parts include the following:

  • Better fatigue resistance
  • Greater resistance to impact, wear, and abrasion
  • Improved ductility

For this process, Paulo’s Cleveland division is equipped with a Quintus QIH-122 HIP vessel, which is specially modified with additional thermocouples for more precise temperature control and greater data collection. A higher level of accuracy allows us to iterate with confidence and find an efficient path to production-ready development.

One primary benefit of the Quintus QIH-122 HIP is the ability to have faster cooling at a controlled rate, which allows you to heat treat and solution treat in one furnace. This cooling rate allows great efficiency that cannot be seen with other HIP vessels on the market.

It is critical that heat treaters adapt to meet the needs of this fast-evolving industry. Many commercial heat treaters do not yet have the level of data or dynamic cycle offerings necessary and will only run HIP coach cycles with set parameters. In other words, many are not equipped to economically iterate and adapt heat treating recipes for new parts. Without custom cycles, controlled cooling, and a higher level of data, it is impossible to push the boundaries of what’s possible.

Space Parts Requiring Thermal Processing

The future of space travel requires parts that can not only perform under high levels of mechanical pressure and extreme temperatures but are also durable enough for long-range and repeat missions. Heat treatment is a critical step in preparing rocket engine components, among others, for commission. Other space components commonly heat treat treated are:

  • Volutes
  • Turbine manifolds
  • Bearing housings
  • Fuel inlets
  • Housings, support housings
  • Bearing supports
  • Turbo components

Since the inception of NASA’s Space Shuttle Program, Paulo has treated integral components for launch and propulsion, along with many parts currently in orbit on the International Space Station.

Materials Used in Space Parts

New materials and applications are being explored every day. Proprietary alloy blends bring unique properties and promising potential in the push for stronger, faster, longer-lasting parts. But with unique properties comes the need for unique heat treating processes. Several high-performance superalloys used for space include:

  • Inconel 718, 625
  • Titanium (Ti-6Al-4V)
  • Hastelloy C22
  • Haynes 214, 282
  • GRCop Copper

Inconel 718, a championed space alloy, was originally used as a premier casting material before being adopted for AM. This nickel-based material features an extremely high tensile and yield strength that makes it ideal for components taking on a high mechanical load in extreme environments ranging from combustive to cryogenic — making this a natural material to adopt for space in the early days of 3D printing.

Because casting and 3D printing both result in similar porous microstructures, the heat treating process used for Inconel castings could also be adapted. Finding new opportunities within existing alloys like this is a highly efficient way to gain material advantage in today’s race to space.

To learn more about adapting alloys and heat treating processes for AM parts, download the full space guide.

About the Author

Noel joined Paulo in 2011 and spent several years as quality manager before stepping into his current role as a metallurgical engineer. Noel holds a bachelor’s degree in engineering and metallurgy materials science, and he is responsible for thermal process development and hot isostatic pressing process development.

For more information: Contact Noel Brady at nbrady@paulo.com or visit this link to download the full space guide from Paulo.

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Thermal Loop Solutions, Part 1: A Path to Improved Performance and Compliance in Heat Treatment

/ AEROSPACE HEAT TREAT, AEROSPACE HEAT TREAT TECHNICAL CONTENT, ATMOSPHERE AIR FURNACES TECHNICAL CONTENT, AUTOMOTIVE HEAT TREAT, AUTOMOTIVE HEAT TREAT TECHNICAL CONTENT, CONTROLS TECHNICAL CONTENT

How often do you think about the intelligent designs controlling the thermal loop system behind your heat treat operations? With ever-advancing abilities to integrate and manage data for temperature measurement and power usage, the ability of heat treat operations to make practical, efficient, and energy-conscious change is stronger than ever. In part 1, understand several benefits of thermal loop systems and how they are leveraged to comply with industry regulations, like Nadcap.

This Technical Tuesday article by Peter Sherwin, global business development manager – Heat Treatment, and Thomas Ruecker, senior business development manager, at Watlow was originally published in Heat Treat Today’s January/February 2024 Air & Atmosphere Heat Treat print edition.

Introduction

Heat treatment processes are a crucial component of many manufacturing industries, and thermal loop solutions have become increasingly popular for achieving improved temperature control and consistent outcomes.

A thermal loop solution is a closed loop system with several essential components, including an electrical power supply, power controller, heating element, temperature sensor, and process controller. The electrical power supply provides the energy needed for heating, the power controller regulates the power output to the heating element, the heating element heats the material, and the temperature sensor measures the temperature. Finally, the process controller adjusts the power output to maintain the desired temperature for the specified duration, providing better temperature control and consistent outcomes.

Performance Benefits

Heat treatment thermal loop solutions offer several advantages over traditional heat treatment methods, including improved temperature control and increased efficiency. The thermal loop system provides precise temperature control, enabling faster heating and cooling and optimized soak times. In addition, the complete design of modern thermal loop solutions includes energy-efficient heating and overall ease of use.

Figure 1. Watlow Industry 4.0 solution (Source: Watlow)

Heat treatment thermal loop solutions are integrated with Industry 4.0 frameworks and data management systems to provide real-time information on performance. Combining artificial intelligence and machine learning algorithms can also provide additional performance benefits, such as the ability to analyze data and identify patterns for further optimization. Ongoing performance losses in a heat treatment system typically come from process drift s. Industry 4.0 solutions can explore these drift s and provide opportunities to minimize these deviations.

Heat treatment thermal loop solutions can be optimized using Failure Mode and Effects Analysis (FMEA). FMEA is a proactive approach to identifying potential failure modes and their effects, allowing organizations to minimize the risk of process disruptions and improve the overall efficiency of their heat treatment processes. Historically, this was a tabletop exercise conducted once per year with a diverse team from across the organization. Updates to this static document were infrequent and were primarily based on organization memory rather than being automatically populated in real time with actual data. There is a potential to produce “live” FMEAs utilizing today’s technology and leveraging insights for continuous improvement.

Th e effectiveness of heat treatment thermal loop solutions can be measured using metrics such as overall equipment effectiveness (OEE). OEE combines metrics for availability, performance, and quality to provide a comprehensive view of the efficiency of a manufacturing process. By tracking OEE and contextual data, organizations can evaluate the effectiveness of their heat treatment thermal loop solutions and make informed decisions about optimizing their operations.

Regulatory Compliance

Nadcap (National Aerospace and Defense Contractors Accreditation Program) is an industry-driven program that provides accreditation for special processes in the aerospace and defense industries. Heat treatment is considered a “special process” under Nadcap because it has specific characteristics crucial to aerospace and defense components’ quality, safety, and performance. Th ese characteristics include:

  • Process sensitivity: Heat treatment processes involve precise control of temperature, time, and atmosphere to achieve the desired material properties. Minor variations in these parameters can significantly change the mechanical and metallurgical properties of the treated components. This sensitivity makes heat treatment a critical process in the aerospace and defense industries.
  • Limited traceability: Heat treatment processes typically result in changes to the material’s microstructure, which are not easily detectable through visual inspection or non-destructive testing methods. Th is limited traceability makes it crucial to have strict process controls to ensure the desired outcome is achieved consistently.
  • Critical performance requirements: Aerospace and defense components often have strict performance requirements due to the extreme conditions in which they operate, such as high temperatures, high loads, or corrosive environments. The heat treatment process ensures that these components meet the specifications and can withstand these demanding conditions.
  • High risk: The failure of a critical component in the aerospace or defense sector can result in catastrophic consequences, including loss of life, significant financial loss, and reputational damage. Ensuring that heat treatment processes meet stringent quality and safety standards is essential to mitigate these risks.

Nadcap heat treatment accreditation ensures suppliers meet industry standards January/February and best practices for heat treatment processes. The accreditation process includes rigorous audits, thorough documentation, and ongoing process control monitoring to maintain high quality, safety, and performance levels.

The aerospace industry’s AMS2750G pyrometry specification and the automotive industry’s CQI-9 4th Edition regulations are crucial for ensuring consistent and high-quality heat treated components. Adherence to these regulations is essential for meeting the stringent quality requirements of the aerospace and automotive industries and other industries with demanding specifications.

Temperature uniformity is a crucial requirement of both AMS2750G and CQI-9 4th Edition, mandating specific temperature uniformity requirements for heat treating furnaces to ensure the desired mechanical properties are achieved throughout the treated components. AMS2750G class 1 furnaces with strict uniformity requirements +/-5°F (+/-3°C) provide both quality output and predictable energy use. However, maintaining this uniformity requires significant maintenance oversight due to all the components involved in the thermal loop.

Calibration and testing procedures are specified in the standards to help ensure the accuracy and reliability of the temperature control systems used in heat treat processes.

Detailed process documentation is required by AMS2750G and CQI-9 4th Edition, including temperature uniformity surveys, calibration records, and furnace classifications. This documentation ensures traceability, enabling manufacturers to verify that the heat treat process is consistently controlled and meets the required specifications.

Figure 2. Eurotherm data reviewer (Source: Watlow)

Modern data platforms enable the efficient collection of secure raw data (tamper-evident) and provide the replay and reporting necessary to meet the standards.

Th e newer platforms also off er the latest industry communication protocols – like MQTT and OPC UA (Open Platform Communications Unifi ed Architecture) – to ease data transfer across enterprise systems.

MQTT is a lightweight, publish-subscribe- based messaging protocol for resource-constrained devices and low-bandwidth, high-latency, or unreliable networks. IBM developed it in the late 1990s, and it has become a popular choice for IoT applications due to its simplicity and efficiency. MQTT uses a central broker to manage the communication between devices, which publish data to “topics,” and subscribe to topics that they want to receive updates on.

OPC UA is a platform-independent, service-oriented architecture (SOA) developed by the OPC Foundation. It provides a unified framework for industrial automation and facilitates secure, reliable, and efficient communication between devices, controllers, and software applications. OPC UA is designed to be interoperable across multiple platforms and operating systems, allowing for seamless integration of devices and systems from different vendors. The importance of personnel and training is emphasized by CQI-9 4th Edition, which requires manufacturers to establish training programs and maintain records of personnel qualifications to ensure that individuals responsible for heat treat processes are knowledgeable and competent. With touchscreen and mobile integration, a significant development in process controls has occurred over the
last decade.

Figure 3. Watlow F4T® touchscreen and Watlow PM PLUS™ EZ-LINK®
mobile application

By integrating these regulations into a precision control loop, heat treatment thermal loop solutions can provide the necessary level of control and ensure compliance with AMS2750G and CQI-9 4th Edition, leading to the production of high-quality heat treated components that meet performance requirements and safety standards.

Continuous improvement is also emphasized by both AMS2750G and CQI-9 4th Edition, requiring manufacturers to establish a system for monitoring, measuring, and analyzing the performance of their heat treatment systems. This development enables manufacturers to identify areas for improvement and implement corrective actions, ensuring that heat treat processes are continuously improving and meeting the necessary performance and safety standards.

To Be Continued in Part 2

In part 2 of this article, we’ll consider the improved sustainability outcomes, potential challenges and limitations, and the promising future this technology offers to the heat treat industry.

About the Authors

Peter Sherwin, Global Business Development Manager – Heat Treatment, Watlow
Thomas Ruecker, Senior Business Development Manager, Watlow

Peter Sherwin is a global business development manager of Heat Treatment for Watlow and is passionate about offering best-in-class solutions to the heat treatment industry. He is a chartered engineer and a recognized expert in heat treatment control and data solutions.

Thomas Ruecker is the business development manager of Heat Treatment at Eurotherm Germany, a Watlow company. His expertise includes concept development for the automation of heat treatment plants, with a focus on aerospace and automotive industry according to existing regulations (AMS2750, CQI-9).

For more information: Contact peter.sherwin@watlow.com or thomas.ruecker@watlow.com.

This article content is used with the permission of heat processing, which published this article in 2023.

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