How long have you been heat treating automotive gears? Which thermal processing techniques do your operations gravitate towards? In this best of the web article, uncover some of the common heat treatment functions and the properties they create in gears. Let us know what you think of this general overview of the world of heat treating gears in our Reader Feedback form!
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Additionally, when you read to the end of the article, future trends that we can anticipate for heat treaters in the automotive industry are offered; as one might guess, they include digital and energy-saving technologies.
An excerpt: “Automotive gear heat treatment (process) includes two aspects: firstly, conventional heat treatment such as annealing, normalizing, quenching, tempering, and quenching and tempering; secondly, surface heat treatment, which encompasses methods like surface quenching (e.g., induction quenching, laser quenching) and chemical heat treatment (e.g., carburizing, carbonitriding, nitriding, nitrocarburizing).”
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 Watlowwas originally published inHeat Treat Today’sJanuary/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, WatlowThomas 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.
Find Heat Treating Products And Services When You Search On Heat Treat Buyers Guide.Com
Thirsting for knowledge about quenching, but not sure where to start? Heat TreatToday has coalesced technical information across articles and podcast episodes from key experts, including significant quenching methods, innovative developments with quenching, and how to control temperature during the process.
Discover more about these three topics in today’s Technical Tuesday original content feature.
Monitor Quench Temperatures with Unique Thermal Barrier Designs
Automotive heat treating operations require repeatable operations to ensure that the composite parts within an automobile perform reliably. Steve Offley, also known as “Dr. O," the product marketing manager at PhoenixTM, outlines case studies of several temperature-critical operations to demonstrate how unique thermal barrier design for thru-process monitoring systems can solve temperature measuring problems. These processes include sealed gas carburizing into an integrated oil quench as well as LPC followed by transfer to a sealed high-pressure gas quench chamber.
Offley comments on the quenching process following LPC, saying, "During the gas quench, the [thermal] barrier [for temperature monitoring] needs to be protected from Nitrogen N2(g) or Helium He(g) gas pressures up to 20 bar." If you are facing heat treat processing with integrated quench, learn more about this temperature monitoring solution.
Intensive Quenching: An Answer for a "Greener" Heat Treat?
Gas furnaces have the potential to be a significant source of carbon emissions in many essential heat treat processes. However, an innovative approach combining induction through heating with intensive quenching could be one answer for greener heat treating, particularly for steel production.
In this article, Chris Pedder,Edward Rylicki, and Michael Aronov share that an “ITH + IQ” technique "eliminates, in many cases, the need for a gas-fired furnace when conducting through hardening and carburizing processes." A lot of this comes down to shortening the time it takes to perform this process, but there is so much more that the authors illuminate in their tests and graphs.
Drinking from a Firehose: Answering Your Quench Questions with a Thorough Radio Review
Stay afloat in a sea of quenching tips with this Heat TreatRadio review, summarizing three recent podcast episodes centered around quenching tips, techniques, and training — especially applying to the auto industry.
Explore the "green" process of salt quenching with Bill Disler of AFC-Holcroft, the topic of water in your quench tank with Greg Steiger of Idemitsu Lubricants America, and a broad review of auto industry quenching with Scott MacKenzie of Quaker Houghton, Inc.
Thinking about travel plans for the upcoming holiday season? You may know what means of transportation you will be using, but perhaps you haven't considered the heat treating processes which have gone into creating that transportation.
Today’s Technical Tuesday original content round-up features several articles from Heat TreatToday on the processes, requirements, and tools to keep planes in the air and vehicles on the road, and to get you from one place to the next.
Standards for Aerospace Heat Treating Furnaces
Without standards for how furnaces should operate in the aerospace, there could be no guarantee for quality aerospace components. And without quality aerospace components, there is no guarantee that the plane you're in will be able to get you off the ground, stay in the air, and then land you safely at your destination.
In this article, written by Douglas Shuler, the owner and lead auditor at Pyro Consulting LLC, explore AMS2750, the specification that covers pyrometric requirements for equipment used for the thermal processing of metallic materials, and more specifically, AMEC (Aerospace Metals Engineering Committee).
This article reviews the furnace classes and instrument accuracy requirements behind the furnaces, as well as information necessary for the aerospace heat treater.
Dissecting an Aircraft: Easy To Take Apart, Harder To Put Back Together
Curious to know how the components of an aircraft are assessed and reproduced? Such knowledge will give you assurance that you can keep flying safely and know that you're in good hands. The process of dissecting an aircraft, known as reverse engineering, can provide insights into the reproduction of an aerospace component, as well as a detailed look into the just what goes into each specific aircraft part.
This article, written by JonathanMcKay, heat treat manager at Thomas Instrument, examines the process, essential steps, and considerations when conducting the reverse engineering process.
If you are one of the growing group of North Americans driving an electric vehicle, you may be wondering how - and how well - the components of your vehicle are produced. Electric vehicles (EVs) are on the rise, and the automotive heat treating world is on the lookout for ways to meet the demand efficiently and cost effectively. One potential solution is laser heat treating.
Explore this innovative technology in this article composed by Aravind Jonnalagadda (AJ), CTO and co-founder of Synergy Additive Manufacturing LLC. This article offers helpful information on the acceleration of EV dies, possible heat treatable materials, and the process of laser heat treating itself. Read more to assess the current state of laser heat treating, as well as the future potential of this innovative technology.
When the Rubber Meets the Road, How Confident Are You?
Reliable and repeatable heat treatment of automotive parts. Without these two principles, it’s hard to guarantee that a minivan’s heat treated engine components will carry the family to grandma’s house this Thanksgiving as usual. Steve Offley rightly asserts that regardless of heat treat method, "the product material [must achieve] the required temperature, time, and processing atmosphere to achieve the desired metallurgical transitions (internal microstructure) to give the product the material properties to perform it’s intended function."
TUS surveys and CQI-9 regulations guide this process, though this is particularly tricky in cases like continuous furnace operations or in carburizing operations. But perhaps, by leveraging automation and thru-process product temperature profiling, data collection and processing can become more seamless, allowing you better control of your auto parts. Explore case studies that apply these two new methods for heat treaters in this article.
Cuáles son las características más deseables de un probador de dureza Brinell? Esta reseña del equipo le permitirá evaluar si debe o no incorporarlo a su departamento de tratamiento térmico.
Read the Spanish translation of this article in the version below or read the English translation when you click the flag to the right. Both the Spanish and the English versions were originally published in Heat Treat Today's August 2023 Automotive Heat Treat print edition.
Toda empresa dedicada al tratamiento térmico deberá practicar ensayos de dureza, algunos de ellos utilizando la medición Brinell que data desde el año 1900, lo que lleva a que se amerite el análisis de tan perdurable técnica. La prueba en mención requiere de un penetrador de bola de carburo de tungsteno que impacte de manera vertical sobre la superficie del material a ser ensayado, previamente ubicado éste sobre un yunque fijo. Paso seguido, se mide el diámetro de la “huella” generada por la bola, mínimo por los ejes “x” y “y,” y se toma el promedio de estas mediciones como cifra operativa de la que se pueda valer el técnico para establecer la dureza, bien sea alimentando una ecuación o mediante la lectura de una tabla de valores en la que se relacione diámetro frente a dureza.
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Para el ensayo Brinell se dispone de una amplia gama de cargas de fuerza, al igual que de diámetros de penetradores, reflejando la gran variedad de metales a ser probados; no obstante, en la mayoría de ensayos se implementa una bola de 10mm bajo una carga de 3.000 kg. En las grandes máquinas de apoyo a suelo por lo general el penetrador es motorizado, aunque otras operan a partir de palancas y pesas, mientras que también las hay hidráulicas o neumáticas.
Existen tres razones principales por las que la prueba Brinell no deja de ser el método más opcionado para la medición de la dureza en muchas industrias de tratamiento térmico.
1. Preparación de la superficie
La preparación de la superficie de una muestra para las pruebas Brinell toma solo unos segundos con una amoladora. Siempre que la muestra esté firmemente asentada sobre el yunque presentando la cara superior en dirección perpendicular a la dirección de la fuerza del penetrador, de acuerdo a lo exigido por las normas, no es necesario lograr una superficie demasiado lisa.
Figura 1. Robusto probador Brinell in situ
2. Contaminación de la superficie
Es poco probable que los contaminantes diminutos en una superficie generen una “prueba errónea” bajo un penetrador Brinell, a diferencia de la prueba de dureza Rockwell (el método más común en la industria). En esta prueba un pequeño indentador de diamante penetra menos de una centésima de pulgada, arrojando como resultado el que cualquier contaminante o anomalía en la superficie que pueda impedir o favorecer el progreso del penetrador (incluído el paralelismo) represente un problema, y obligando a que las muestras para la prueba Rockwell se deban preparar cuidadosamente antes de realizar la misma.
3. Portabilidad
Quizás el factor más significativo es que los robustos equipos portátiles de mano Brinell, con cabezales de prueba hidráulicos, permiten probar, in situ, piezas grandes, pesadas, de superficies rugosas o formas irregulares. Esta característica es de tal utilidad en la industria que ha motivado a que los órganos de normalización internacional otorguen una dispensación especial, una excepción si se quiere, a las máquinas portátiles, pese a que la ejecución de las mismas no sea susceptible de verificación directa como sí lo es la de sus equivalentes, las máquinas fijas.
Con fuerzas que van desde los 3000 kg hasta 1 kg, y bolas penetradoras tan pequeñas como 1 mm, las pruebas Brinell se pueden usar en una amplia gama de metales, pero los lugares en los que existiría la mayor probabilidad de encontrar un equipo de 10mm/3000kg son las forjas, las fundiciones, las plantas de tratamiento térmico, los laboratorios y las áreas de control de calidad. Previamente mencionamos que no se requiere que la superficie de las muestras de prueba sea absolutamente lisa; de hecho, es posible medir con un grado importante de precisión las superficies irregulares en materiales de configuración gruesa ya que el diámetro de la hendidura es tan grande en relación con cualquier irregularidad en la superficie.
Figura 2. Probador de Brinell, grado calibrador, en primer plano
En la Figura 2 se puede apreciar cómo un probador Brinell de grado calibrador introduce la bola de carburo de tungsteno en la muestra de prueba. Se mantiene la bola en posición para estabilizar la deformación plástica.
Las normas que rigen de manera detallada las pruebas Brinell son la ASTM E-10 y la ISO 6506, pero el procedimiento práctico para los técnicos es muy sencillo, tanto que el entrenamiento no debería tardar más de una hora. Para ensayar piezas forjadas, palanquillas y otras muestras, una hendidura debería bastar aunque, desde luego, en ciertas aplicaciones de extrema importancia se podrá utilizar más de una para mayor seguridad.
Saber si analizar o no cada muestra en un lote determinado deberá decidirse con base en la inconsistencia de las muestras mismas, más no responde a problemática alguna con las pruebas de Brinell en sí. En ciertas industrias se prueba cada pieza que se produce debido a que el riesgo de error es demasiado alto. Un buen ejemplo lo encontramos en la producción de los componentes de los eslabones para las orugas utilizadas en tanques y maquinaria pesada (retroexcavadoras y demás). Cada eslabón de cada oruga de un tanque en uso en el ejército británico ha sido probado por Brinell en una máquina totalmente automática, de alta velocidad, que cuenta con una poderosa abrazadera integral para mantener el componente absolutamente rígido durante la prueba. Por cierto, esa máquina es la de la primera foto. Con un cuidado adecuado y razonable, un probador Brinell robusto podrá generar cientos de miles de pruebas; de hecho, el probador de la Figura 1 ha realizado varios millones.
Las pruebas duran aproximadamente quince segundos ya que el penetrador se debe dirigir hacia el material de manera uniforme sin permitir la posibilidad de un “rebote” y evitando por completo llegar a golpear el material. Por otro lado, el metal debe recibir la presión por un período de tiempo suficiente que garantice que la hendidura se deforme de la manera más plástica posible, es decir, minimizando al máximo el riesgo de la más ligera contracción de la hendidura una vez retirado el penetrador.
Figura 3. Medición de una hendidura de prueba de dureza Brinell
Sin embargo, es en este punto que se presentan las complicaciones. Después de generar cuidadosamente la hendidura y retirar la muestra de prueba de la “boca” de la máquina probadora, es necesario medir la hendidura en al menos dos diámetros. Dado que las hendiduras de Brinell tienen como máximo 6 mm de ancho y que una diferencia de 0,2 mm en el diámetro podría equivaler a 20 puntos de dureza, obtener la medición correcta es esencial y de alta complejidad. La mayoría de los técnicos usan un microscopio iluminado para lograrlo, pero aún así puede ser un desafío. Considere la Figura 3.
Los microscopios de medición manual han mejorado a lo largo de los años, y cuando se obtiene una hendidura relativamente “limpia” con una retícula nítidamente iluminada, se le puede facilitar al técnico experimentado realizar una medición precisa. La Figura 4 presenta un escenario menos complejo que el anterior pero, aun así, ¿cómo podemos saber si realmente se ha juzgado con precisión la posición del borde?
Figura 4. Medición con microscopio mejorado y retícula bien iluminada.
Al crearse la hendidura se genera un cordoncillo en el perímetro de la misma debido a que el metal no solo presiona hacia abajo, sino también hacia los lados. Este cordoncillo puede difi cultar la ubicación del punto en el que comienza realmente la hendidura, y tres técnicos diferentes pueden hacer fácilmente tres estimaciones diferentes de su lugar de inicio. Es esta variación en la interpretación de los resultados por parte de los operadores la que ha llevado a que, durante más de 80 años, la prueba Brinell se haya considerado un poco “ordinaria”, apta tal vez para el maquinista en el taller, pero de dudoso valor para el científi co en el laboratorio.
En 1982 llegó a los mercados el primer lector automático, siendo éste la culminación de años de investigación, y valiéndose de software privado que llevó a las computadoras de la época a sus límites. El equipo podía hacer cientos de mediciones de un lado a otro de la hendidura y calcular el diámetro medio en una fracción de segundo. Poco después llegó a ser parte integral de una máquina de prueba Brinell. La noticia de la aparición de este equipo pronto llegó a algunos usuarios importantes en la industria de las herramientas petroleras quienes exigieron a sus proveedores valerse de él; quince años más tarde se había diseminado ampliamente el uso de esta tecnología generando la transformación de la percepción que se tenía de la prueba Brinell. Podríamos decir que la prueba Brinell había llegado a la mayoría de edad.
Figura 5. La última versión de ese microscopio automático en acción
Desde luego, como con cualquier equipo de medición importante, la calibración y el mantenimiento regulares son aconsejables, si no obligatorios. Los fabricantes mismos suelen estipular un cronograma de mantenimiento que se debe tener en cuenta junto con las reglas de calibración establecidas por las agencias internacionales.
Al considerar las opciones para la prueba de dureza en muestras con tratamiento térmico, en última
instancia existen tres métodos: Brinell, Rockwell y Microdureza (Vickers o Knoop).
Pese a que no es adecuada para muestras muy pequeñas o demasiado delgadas, la prueba Brinell es relativamente “inmune” a los contaminantes pequeños, los penetradores no son costosos, y, gracias al ancho de la hendidura, las pruebas de superficies con acabado áspero e irregular no presentan dificultades. Con el desarrollo, hace 40 años, de la medición automática de la hendidura, se superó la única deficiencia grave de la prueba Brinell, proporcionando las garantías que tan vital importancia revestían para los proveedores de piezas esenciales en industrias de toda índole, incluídas las de petróleo y gas, aeroespaciales y de defensa y transporte.
Sobre el autor: Alex Austin se viene desempeñando desde 2002 como gerente de Foundrax Engineering Products Ltd. Foundrax es proveedor de equipos de prueba de dureza Brinell desde1948, siendo en realidad la única compañía en el mundo especializada en el campo.
Alex funge en el Comité de Prueba de Dureza por Hendidura ISE/101/05 del British Standards Institution. En su calidad de miembro de la delegación británica de la Organización Internacional de Normalización, ha aportado como consultor para el desarrollo de la norma ISO 6506 “Materiales metálicos–prueba de dureza Brinell” y preside en la actualidad la revisión ISO de dicha norma.
What are the most desirable attributes of a Brinell hardness tester? Does it belong in your heat treat department? Read this equipment overview to decide.
Read the English translation of this article in the version below or read the Spanish translation when you click the flag to the right. Both the Spanish and the English versions were originally published in Heat Treat Today's August 2023 Automotive Heat Treat print edition.
Alex Austin
Managing Director
Foundrax Engineering Products Ltd
Source: Foundrax
All heat treatment companies must test hardness; many with a Brinell tester. Existing since 1900, a review of this time-tested method is in order.
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The Brinell test requires a tungsten carbide ball indenter to be forced vertically into the surface of the test material, placed on a rigid anvil. The diameter of the indentation made by the ball is then measured across both its x and y axes as a minimum, and the average of these measurements is taken as the working figure. The technician can then either feed that figure into an equation to determine the hardness or read from a “diameter-to-hardness” chart.
There are various forces and indenter diameters available for Brinell testing reflecting the very wide range of metals that need to be assessed, but most tests involve a 10 mm ball under a 3,000 kg load. In large, floor standing machines, the indenter is usually motor-driven, but some machines use levers and weights, while others are hydraulic or pneumatic. The Brinell test remains the default method for hardness measurement in many heat treatment facilities, for three primary reasons.
1. Surface Preparation
Preparing the surface of a sample for Brinell testing takes just a few seconds with a grinder. Provided the sample is sitting steadily on the anvil and the top face of the sample is perpendicular to the direction of force of the indenter — as mandated by the standards — the surface does not need to be particularly smooth.
Figure 1. Heavy-duty Brinell tester in situ
2. Surface Contamination
Minute surface contaminants under a Brinell indenter are unlikely to cause a “mis-test.” By comparison, during Rockwell testing, the most widely used method across all industries, a tiny diamond indenter penetrates the surface by less than one hundredth of an inch, and any contaminants or surface abnormalities (including parallelism) that could impede or assist the progress of the indenter are a problem, which means that Rockwell samples must be carefully prepared before testing.
3. Portable
Perhaps most significant, rugged, hand-held portable Brinell testers with hydraulic test heads enable large, heavy, and awkwardly shaped components of rough surface finish to be tested in situ. This feature is of such utility in industry that the international standards authorities give a dispensation — a special designation — to portable machines, although their performance cannot be directly verified like their floor-standing cousins.
With forces ranging from 3000 kg down to 1 kg and indenter balls as small as 1 mm, Brinell testing can be used on a vast range of metal, but forges, foundries, heat treatment plants, quality control areas, and laboratories are the places one would most likely find a test machine working at 10 mm/3000 kg. It was mentioned earlier that the surface of test samples doesn’t need to be particularly smooth, in fact roughly- ground surfaces on materials with a coarse grain structure can be measured quite safely because the diameter of the indentation is so large relative to any irregularities on the surface.
Figure 2. Close-up of a calibration-grade Brinell tester
In Figure 2, a calibration-grade Brinell tester drives the tungsten carbide ball into the test sample. The ball is being held in position to stabilize plastic deformation. ASTM E-10 and ISO 6506 — the authoritative documents for Brinell testing — lay out standards in detail, but the practical procedure for workshop technicians is very straightforward; training should not take longer than an hour. When testing forgings, billets, and other samples, one indentation should suffice but in certain critical applications more than one indentation may be used for assurance.
The question of whether to test every sample in a batch will depend on how inconsistent those samples might be; it has nothing to do with any issues with Brinell testing itself. In certain industries, every single product is tested because the risk of failure is too high. A good example of this is the production of links for the tracks used on tanks and other armored vehicles. Every link in every tank track in use by the British Army has been Brinell tested on a high-speed, fully automatic machine that features a powerful integral clamp to keep the component rigid during the test. You can view the machine in Figure 1 on page 44. Subject to reasonable care, a heavy-duty Brinell tester will perform many hundreds of thousands of tests. The machine in Figure 1 has performed several million.
Tests take approximately fifteen seconds. The indenter must be driven uniformly into the material with no possibility of either a rebound or a speed that would “punch” the indenter into the material. Also, the metal must be loaded for a sufficient length of time to ensure the indentation is properly (plasticly) deformed, that is, the risk of an indentation shrinking very, very slightly after the indenter is withdrawn is kept to a minimum.
Figure 3. Measurement of Brinell hardness test indentation
Measuring the indentation is more challenging. After carefully making the indentation and withdrawing the test sample from the “jaws” of the test machine, one must measure the indentation across at least two diameters. Given that Brinell indentations are at most 6 mm across and that 0.2 mm difference in diameter might equal 20 hardness points, getting the measurement right is critical — and tricky. Most technicians will use an illuminated microscope to do this, but even then it can be a challenge. Consider Figure 3 on the next page.
Making an indentation leaves a “ridge” at the indentation perimeter because metal is not just pushed downwards, but also sideways. This ridge can obscure where the real indentation begins, and three different technicians can easily make three different estimates of where that is. And this variation in operators’ interpretation of results is why, for over 80 years, the Brinell test was seen as a little “rough and ready,” for the workshop machinist, perhaps, but probably not for the laboratory scientist.
Manual measurement microscopes have improved over the years, and a relatively “clean edged” indentation with a crisply illuminated graticule can be less challenging for the experienced technician to make an accurate measurement. Figure 4 is a less difficult scenario than the one above. Even so, how can we know if we have really judged the position of the edge precisely?
Figure 4. Measurement with improved microscope and well-illuminated graticule
In 1982, the first automatic reader hit the markets. This was the culmination of years of research and used proprietary software that pushed the computers of the day to their limits. The equipment could make hundreds of measurements across the indentation and calculate the mean diameter in a split second. Not long afterwards, it was available as an integral part of a Brinell test machine. Word of this equipment soon reached critical users in the oil tool industry, and they mandated its use to their suppliers. Within 15 years, the use of this technology was widespread and the perception of the Brinell test’s accuracy had been transformed. The Brinell test, in a sense, had come of age. See Figure 5 for the latest version of that automatic microscope in action.
Finally, like any important measuring equipment, regular calibration and servicing is desirable, if not compulsory. Manufacturers typically stipulate a service schedule which must be considered alongside the calibration rules dictated by international agencies.
When considering options for hardness testing of heat treated samples, there are ultimately three test methods: Brinell, Rockwell, and Microhardness (Vickers or Knoop).
Figure 5. Latest version of the automatic microscope in action
While Brinell testing isn’t suited to very small or very thin samples, it is relatively “immune” to small contaminants, the indenters are not expensive, and the width of the indentation means that testing of coarse grained and roughly finished surfaces is not problematic. With the development of reliable automatic indentation measurement, the one serious deficiency of the Brinell test was overcome, providing the assurance that was vital to critical components suppliers in all types of industries such as oil and gas, aerospace, defense, and transportation.
About the Author:
Alex Austin has been the managing director of Foundrax Engineering Products Ltd. since 2002. Foundrax has supplied Brinell hardness testing equipment since 1948 and is the only company in the world to truly specialize in this field. Alex sits on the ISE/101/05 Indentation Hardness Testing Committee at the British Standards Institution. He has been part of the British delegation to the International Standards Organization advising on the development of the standard ISO 6506 “Metallic materials – Brinell hardness test” and is the chairman and convenor for the current ISO revision of the standard.
For more information:
Contact www.foundrax.co/uk.
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Are your brake rotors heat treated? Travel back in time to discover how ferritic nitrocarburizing (FNC) became the heat treatment of choice for automakers’ brake rotors and why the tip-up furnace forever altered the production process for this part.
This Technical Tuesday article is drawn from Heat Treat Today's February Air & Atmosphere Furnace Systems print edition.If you have any information of your own about heat treating brake rotors, our editors would be interested in sharing it online at www.heattreattoday.com. Email Bethany Leone at bethany@heattreattoday.com with your own ideas!
The Problem: Brake Rotor Corrosion
Michael Mouilleseaux General Manager at Erie Steel, Ltd. Sourced from the author
In the early 2000s, corrosion was one of the top three issues that U.S. automotive manufacturers found negatively affected the perception of the quality of their cars. Brake rotors are made of cast iron. These components sit out in the elements, and in places like the U.S. Midwest where salt is often used on the roads, unprotected steel or iron will corrode or rust. Even on the coast, there is salt water in the air.
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What does rusting cause? The rotor rusts, and first, the cosmetics are negatively affected (i.e., rusty appearance). But more importantly, the first time you step on the brakes, it squeals like a pig, the vehicle shudders, and the driver feels pulsing in the pedal. He’ll also feel it in the steering wheel because the amount of rust coating one area is different from the amount of rust that’s on another. So, these brand new, forty- to seventy-thousand-dollar cars have orange rust over the brake rotor and a shaky drive. . . it’s not a good look!
Now, this is just a superficial coating of rust that will eventually abrade away; the rotor will look alright, the vehicle will stop better, and it won’t squeal. However, since the rust on the rotor wears off unevenly, the car may never have smooth braking.
A Move to FNC
In the early 2000s, all the big players were looking to FNC (ferritic nitrocarburizing) as a solution to corrosion, including Bosch Braking Systems, Ford, General Motors, Akebono, and the truck manufacturers. FNC was becoming popular since the process adds a metallurgical layer — called the “white layer” or “compound zone” — to the part, providing corrosion resistance and the bonus of improving wear.
Source: Oleksandr Delyk/Adobe Stock
To the OEMs, the benefits were perceived as:
The corrosion issue had an answer.
The life of the rotor doubled from roughly 40,000 to 80,000 miles. Although that meant half as many aftermarket brake jobs compared to before, consumers perceived it as a real advantage.
The rotors generated less dust. Brakes generate dust particles as the result of abrasion of the pads and the rotors. This particulate dust has been identified as both an environmental and a health concern. Now, flash forward to 2022: Electric vehicles are largely displacing the need to control emissions from ICE (internal combustion engine) vehicles. So, the new European standard on vehicle emissions implemented a requirement to control this dust that is harmful to the environment and which EV and traditional brake systems can emit.
But there were certain technical and practical challenges that automotive manufacturers faced when trying to implement this process at scale.
#1 Distortion. Brake rotors may distort during FNC. Since rotors are (gray iron) castings, the process temperature for FNC may stress relieve the rotor, causing it to change shape or distort, rendering it unusable as a disc brake rotor. It was determined that if the rotor castings were stress relieved prior to machining and FNC, the distortion issue was rendered moot.
#2 Loss of Necessary Friction. FNC gives the white layer on the surface of a part with a diffusion zone underneath. The compound zone has a very low coefficient of friction, which means excellent wear properties. However, manufacturers want friction between the rotor and the brake pads to slow the car down. Reducing the friction on the rotors extends the braking distance of the car.
". . .[M]anufacturers want friction between the rotor and the brake pads to slow the car down." Source: Unsplash.com/Craig MorolfLet me illustrate this: I ferritic nitrocarburized a set of brake discs for Bosch Braking Systems, which eventually went to Germany and then on a vehicle. The customer absolutely loved the corrosion resistance, but when it was time for the downhill brake test, the car went straight through an instrument house because the brakes couldn’t stop the car! Lesson: For rotors treated with FNC, the brake pads need to be made from a different frictional material!
#3 Cost. Overcoming the technical issues is simple. Stress relieving the casting at FNC temperatures before machining it would help the parts machine better and would eliminate distortion. Modifying the FNC process could reduce the depth of the white layer and, paired with the correct friction material, the acceptable braking capabilities were restored. Yet these additional steps presented a new challenge: higher costs.
The practical constraints of FNC in conventional batch or pit furnaces strained efforts to be cost-effective. The load (size) capacity of the conventional equipment, in conjunction with the time constraints of the FNC process presented a dilemma, as the OEMs’ benchmark was about one dollar per rotor.
Here Comes the Tip-Up
With traditional furnaces for FNC, there was just no way to reach the economics that were necessary for it. A bigger pit furnace might be the way to go, but they really weren’t big enough. So, here comes the tip-up.
Traditionally, a tip-up furnace has been used for processes with just air, no atmosphere. With direct fired burners, the furnace is used for tempering, stress relieving, annealing, and normalizing. Everything loads into the box, gets fired, and unloads, similar to a car-bottom furnace. With the appropriate external handling systems parts could be retrieved from the furnace and then quenched. This additional process increased the usefulness of the equipment and allowed for the processing of tubes, bars, big castings. . . big forgings for the oil industry and the like.
The question of how to heat treat brake rotors on a large scale still needed to be answered. It required a large, tightly sealed furnace with atmospheric integrity for excellent temperature uniformity. In ferritic nitrocarburizing, the processing range is about 950°F to 1050°F. It is well known that properties vary significantly across the temperature range. And they needed to be optimized to create the appropriate frictional properties for the rotors.
So, the answer was: Let’s make a tip-up furnace that can be sealed for atmospheric integrity, has the appropriate temperature uniformity, and can circulate gas evenly. A lot of this would have to be iterative — create, test, compare, repeat.
Tip-up furnace from Gasbarre Thermal Processing Systems Source: Gasbarre Thermal Processing Systems
The development of the perfect tip-up was essentially the work of one furnace manufacturer and one heat treater who together changed the industry.
American Knowhow Makes the Perfect Tip-Up
In the early 2000s, heat treaters worked with OEMs to develop a cost-efficient process in a tip-up. Manufacturers and service providers tested different methods, including atmosphere FNC and salt bath FNC.
By 2009, the perfect atmosphere furnace was complete and high volume brake rotors began to be processed for General Motors. The furnace manufacturer was JL Becker, Co., acquired by Gasbarre in 2011. The commercial heat treater was Woodworth, Inc., located in Flint, MI. Together, they spent a lot of time and money looking into FNC and figuring out how to make it work in a tip-up furnace.
General Motors was the first one to get on board, utilizing the FNC processed rotors on their pickup trucks and big SUVs, like the Escalade and Tahoe. Ford was not far behind using it on their F150 pickup truck. I was shocked the first time I saw the commercial: a Silverado pickup truck, out in the snow, and the speaker saying, “We now have an 80,000-mile brake system because of a heat treating process called FNC!”
It’s a great story of American knowhow and a collaborative effort between someone who saw a need and someone else who saw the way. To this day, if you want to get a replacement set of brake rotors for your car, go to a place like AutoZone; they will tell you that the difference in cost between the OEM parts and an off-brand is the fact that the off-brand is not heat treated.
About the author: Michael Mouilleseaux has been at Erie Steel, Ltd. in Toledo, OH, since 2006 with previous metallurgical experience at New Process Gear in Syracuse, NY, and as the Director of Technology in Marketing at FPM Heat Treating LLC in Elk Grove, IL. Having graduated from the University of Michigan with a degree in Metallurgical Engineering, Michael has proved his expertise in the fi eld of heat treat, co-presenting at the Heat Treat 2019 show and currently serving on the Board of Trustees at the Metal Treating Institute.
Vacuum furnaces are widely used in the aerospace and automotive industries. These furnaces are used for multiple processes including brazing, aging, and solution heat treating for countless materials. Typically, vacuum furnaces are utilized to ensure a lack of oxidation/contamination during heat treatment. This article will talk about the origins, theory, and main parts of vacuum technology and how it is used in both aerospace and automotive industries.
This Technical Tuesday feature was written by Jason Schulze, director of technical services at Conrad Kacsik Instrument Systems, Inc., and was first published in Heat Treat Today's December 2022 print edition.
A Brief History
Vacuum furnaces began to be used in the 1930s for annealing and melting titanium sponge materials. Early vacuum furnaces were hot wall vacuum furnaces, not cold wall vacuum furnaces like we use today. Additionally, most early vacuum furnaces did not utilize diffusion pumps.
Vacuum Heat Treat Theory
Vacuum technology includes vacuum pumping systems which enable the vessel to be pulled down to different stages through the process. Degrees of vacuum level are expressed opposite of pressure levels: high vacuum means low pressure. In common usage, the levels shown below in Figure 1 correspond to the recommendations of the American Vacuum Society Standards Committee.
Vacuum level will modify vapor pressure in a given material. The vapor pressure of a material is that pressure exerted at a given temperature when a material is in equilibrium with its own vapor. Vapor pressure is a function of both the material and the temperature. Chromium, at 760 torr, has a vapor pressure of ~4,031°F. At 10¯5, the vapor pressure is ~2,201°F. This may cause potential process challenges when processing certain materials in the furnace. As an example, consider a 4-point temperature uniformity survey processed at 1000°F, 1500°F, 1800°F, and 2250°F. This type of TUS will typically take 6-8 hours and, as the furnace heats up through the test temperatures, vacuum readings will most likely increase to a greater vacuum level. If expendable Type K thermocouples are used, there is a fair chance that, at high readings, you may begin to have test thermocouple failure due to vapor pressure.
Figure 1. Vacuum levels corresponding to the recommendations of the American Vacuum Society Standards Committee
Source: Jason Schulze, Conrad Kacsik Instrument Systems, Inc.
Vacuum Furnace Pumping System
Vacuum heat treating is designed to eliminate contact between the product being heat treated and oxidizing elements. This is achieved through the elimination of an atmosphere as the vacuum pumps engage and pulls a vacuum on the vessel. Vacuum furnaces have several stages to the pumping system that must work in sequence to achieve the desired vacuum level. In this section we will examine those states as well as potential troubleshooting methods to identify when one or more of those stages contributes to failure in the system.
Vacuum furnaces have several stages to the pumping system that must work in sequence to achieve the desired vacuum level. Each pump within the system has the capability to pull different vacuum levels. These pumps work in conjunction with each other (see Figure 2).
Figure 2. Vacuum pumps work in conjunction with one another
Source: Jason Schulze, Conrad Kacsik Instrument Systems, Inc.
The mechanical pump is the initial stage of vacuum. This pump may pull from 105 to 10. At pressures below 20 torr the efficiency of a mechanical pump begins to decline. This is when the booster pump is initiated.
The booster pump has two double-lobe impellers mounted on parallel shafts which rotate in opposite directions (see Figure 3).
Figure 3. Booster pump positions
Source: Jason Schulze, Conrad Kacsik Instrument Systems, Inc.
The diffusion pump (Figure 4) is activated into the pumping system between 10 and 1 microns. The diffusion pump allows the system to pump down to high vacuum and lower. The diffusion pump has no moving parts.
Figure 4. Diffusion Pump
Source: Jason Schulze, Conrad Kacsik Instrument Systems, Inc.
The pump works based on the vaporization of the oil, condensation as it falls, and the trapping and extraction of gas molecules through the pumping system.
Image 1. Holding Pump
Source: Jason Schulze, Conrad Kacsik Instrument Systems, Inc.
The holding pump (Image 1) creates greater pressure within the fore-line to ensure that, when the crossover valve between the mechanical and diffusion pump is activated, the oil within the diffusion pump will not escape into the vessel.
Vacuum Furnace Hot Zone Design
Image 2. Insulated
Source: Jason Schulze, Conrad Kacsik Instrument Systems, Inc.Image 3. Radiation
Source: Jason Schulze, Conrad Kacsik Instrument Systems, Inc.
The hot zone within a vacuum furnace is where the heating takes place. The hot zone is simply an insulated chamber that is suspended away from the inner cold wall. Vacuum itself is a good insulator so the space between the cold wall and hot zone ensures the flow of heat from the inside to the outside of the furnace can be reduced. There are two types of vacuum furnace hot zones used: insulated (Image 2) and radiation style (Image 3).
The two most common heat shielding materials are molybdenum and graphite. Both have advantages and disadvantages. Below is a comparison (Tables 1 and 2).
Table 1
Source: Jason Schulze, Conrad Kacsik Instrument Systems, Inc.Table 2
Source: Jason Schulze, Conrad Kacsik Instrument Systems, Inc.
Vacuum Furnace Quenching System
Quenching is defined as the rapid cooling of a metal to obtain desired properties. Different alloys may require different quenching rates to achieve the properties required. Vacuum furnaces use inert gas to quench when quenching is required. As the gas passes over the load, it absorbs the heat which then exits the chamber and travels through quenching piping which cools the gas. The cooled gas is then drawn back into the chamber to repeat the process (see Figure 5).
Figure 5.Diagram of gas quenching
Source: Jason Schulze, Conrad Kacsik Instrument Systems, Inc.
Vacuum Furnace Trouble Shooting
In Table 3 are some helpful suggestions with regard to problems processors may have.
Table 3
Source: Jason Schulze, Conrad Kacsik Instrument Systems, Inc.
Summary
Vacuum furnaces are an essential piece of equipment when materials need to be kept free of contamination. However, there are times when this equipment may not be necessary, and is therefore considered cost prohibitive, although this is something each processor must research. This article is meant to merely touch on vacuum technology and its uses. For additional and more in-depth information regarding vacuum furnaces, I recommend a technical book called Steel Heat Treatment, edited by George E. Totten.
About the Author: Jason Schulze is the director of technical services at Conrad Kacsik Instrument Systems, Inc. As a metallurgical engineer with over 20 years in aerospace, he assists potential and existing Nadcap suppliers in conformance as well as metallurgical consulting. He is contracted by eQuaLearn to teach multiple PRI courses, including pyrometry, RCCA, and Checklists Review for heat treat.
Twice a month, Heat TreatToday publishes an episode of Heat TreatRadio, an industry-specific podcast that covers topics in the aerospace, automotive, medical, energy, and general manufacturing realms. Each episode provides industry knowledge straight from the experts.
Stay abreast of quenching tips, techniques, and training --- especially in the auto industry --- with this original content piece that draws from three video/audio episodes.
Heat Treat Radio: The Greenness and Goodness of Salt Quenching with Bill Disler
Bill Disler President, CEO AFC-Holcroft Source: AFC-Holcroft
Sure, salt quenching has been around for quite some time, but this method is coming more to the forefront when we consider some of the concerns and costs of oil quenching. In this Heat TreatRadioepisode, listen in to Bill Disler of AFC-Holcroft discuss the pros and cons of salt quenching. His brief overview and then salt versus other quench options will leave you ready to embrace quenching at your heat treat shop.
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"I’d say, in general, the most common thoughts with salt are to use it for bainitic quenching. If you’re quenching into a bainitic structure, salt has always been the only way to do this," comments Bill. "But what we’re seeing the growth into, and much more activity, is martensitic quench." As you listen, key into the point of salt quenching offering a "green-minded" solution due to recyclability.
Heat Treat Radio: Water in Your Quench with Greg Steiger, Idemitsu
Greg Steiger Senior Key Account Manager Idemitsu Lubricants America
Water in the quench tank? How much is too much? What do you do to get rid of it? Is it possible to prevent water from getting into the tank? Greg Steiger of Idemitsu answers these questions and more in this essential episode.
"Our research has shown that basically about 200-250 ppm water, you start to get uneven cooling," Greg Steiger cautions. "When you start getting up to large amounts of water, somewhere around 750 ppm to over 1000 ppm, it becomes a safety issue."
The entire episode gives answers to how to identify, prevent, and remove water in the quench.
Heat Treat Radio: All Things Auto Industry Quenching with Scott MacKenzie
D. Scott MacKenzie, Ph.D Senior Research -- Metallurgy Quaker Houghton, Inc.
This interview gets to some nitty gritty details regarding quenching and the shift to electric vehicles. What does the future of heat treating look like for electric vehicles (EVs)? Where is aluminum heat treat fitting in? Listen in to get industry insight on these answers. Scott MacKenzie of Quaker Houghton also explores simulation and modeling, the need for trained metallurgists in our industry, and more broad heat treat considerations.
"The next thing you have to understand is the quenchant itself," Scott MacKenzie advises. "You have to understand the physical properties."
Are you a relatively new reader in automotive heat treat? Welcome. Enjoy this archive of articles from the automotive industry, which provides years of technical knowledge to fill any information gaps. Even the "OG" readers with Heat TreatTodaywill want to investigate this Technical Tuesday original content compilation that plumbs the depths of the archives.
1. What Heat Treatment To Use for Truck Gear Boxes?
This paper reveals the investigation and conclusions of distortion potentials for case hardening processes. Mainly, the focus was on how the SyncroTherm® concept method compared to conventional case-hardening processes for gears and sliding sleeves.
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Read about how the results effected the bottom line: reduced costs, quicker processes, and less distortion. Also, be sure to examine each of the charts and figures for further understanding of each test.
This article entered the Automotive Heat Treat archive in 2016, and was written by Andreas Schüler, Dr.-Ing. Jörg Kleff, Dr. Volker Heuer, Gunther Schmitt, and Dr. Thorsten Leist.
Problems in heat treating result in the loss of valuable time and money. Getting to the bottom of those problems also usually takes time and money to investigate what's happening and how to fix it. What is a heat treater to do?
In this article, we follow a case study from the automotive industry to understand how to pinpoint a heat treating problem. This article specifically looks at what was causing cracking in variable valve timing (VVT) plates.
3. Carburizing: The Importance of Temperature Monitoring and Surveying
Low pressure carburizing (LPC) furnaces play an important role in the automotive heat treating industry. During LPC, it is essential that processing temperature stays consistent and critical that the processing time frame is monitored.
This article discusses the importance of collecting temperature data and what to do with the data when it's been collected.
4. Vacuum Brazing --- Back to the (Automotive) Basics
Time to brush up on a vacuum brazing furnace, but automotive industry style. Review the terms, parts, function, and more that are involved in a successful vacuum braze for automotive parts.
This study covers a semi-automatic TAV vacuum brazing furnaces, details the makeup of the furnace, and gives an idea of what happens with a load from start to finish.
5. Saving Time --- Automation Versus Manual Hardness Tests
If you've ever heat treated automotive crank pins, you're probably familiar with at least one type of hardness test that case hardened crank pins are tested against. The big question is, which hardness testing method is better: automated or manual? This article compares these two methods to make and measure Vickers indentations.
Evaluate for yourself the comparisons between an experienced operator manually entering data to Wilson VH3100 series Vickers Microhardness Tester and a DiaMet software entry. Some additional findings show that the crank pins could be examined by the Wilson tester with far less manipulation in the vice as well as reduction in data recording mistakes.
This paper reveals the investigation and conclusions of distortion potentials for case hardening processes. Mainly, the focus was on how the SyncroTherm® concept method compared to conventional case-hardening processes for gears and sliding sleeves.
Problems in heat treating result in the loss of valuable time and money. Getting to the bottom of those problems also usually takes time and money to investigate what's happening and how to fix it. What is a heat treater to do?
Low pressure carburizing (LPC) furnaces play an important role in the automotive heat treating industry. During LPC, it is essential that processing temperature stays consistent and critical that the processing time frame is monitored.
Time to brush up on a vacuum brazing furnace, but automotive industry style. Review the terms, parts, function, and more that are involved in a successful vacuum braze for automotive parts.
If you've ever heat treated automotive crank pins, you're probably familiar with at least one type of hardness test that case hardened crank pins are tested against. The big question is, which hardness testing method is better: automated or manual? This article compares these two methods to make and measure Vickers indentations.