Stress corrosion cracking is an insidious form of damage that can occur when a susceptible metal is subjected to a tensile stress in a specific environment. To relieve tensile stresses at welded joints, postweld heat treatment can be helpful in reducing the susceptibility of carbon steel fabrications to SCC. When planning to use stainless steels in chloride-containing environments, it is advisable to select alloys that have been specifically developed to resist stress chloride cracking such as ferritic-austenitic (duplex) alloys, low-carbon ferritic alloys, and 6% Mo austenitic alloys or to select high-nickel alloys.

The Heat Treating Society R&D Committee, under the direction of Michael Pershing, Caterpillar, has compiled a list of organizations conducting research related to heat treating. Each listing includes contact information and selected projects.

4D high-pressure gas quenching ensures uniform heating and quenching for precise, repeatable results while reducing distortion. This article describes the process and equipment for 4D high-pressure gas quenching and gives some examples.

Martempering involves cooling steel from the austenitizing temperature and rapidly cooling into either specially formulated petroleum oil or a molten salt bath with a specific composition to a temperature slightly above the martensite start (Ms) transformation temperature of the steel. Martempering is performed to reduce distortion problems that may be encountered with conventional quenching methods. This article, adapted from the latest ASM Handbook on quenching and quenchants, describes suitable steels for martempering and variables that influence the process.

Getting connected and using data for operations and maintenance decisions is a great place to start when implementing Industry 4.0 concepts. This article reviews the steps that heat treaters must take toward adopting this technology, with an emphasis on implementing or enhancing predictive maintenance capabilities.

The hands-on experience provided during an Eisenman Materials Camp for students is a compelling way to excite young people to consider a STEM career. The volunteer-lead curriculum pairs a weeklong failure analysis project with many hands-on heat treating, metal casting, and materials characterization experiments. This article provides background about the Eisenman camp as well as the other student camps organized by the ASM Materials Education Foundation and discusses their benefits and long-term impact.

An examination of a bearing failure due to mismatched and incomplete flame hardening shows the need to work with heat treaters for proper selection and application. The article includes a case study of a large bearing raceway that failed due to incomplete austenitization.

Integral quenching (IQ) is a widely adopted heat treatment technique known for its efficient and rapid quenching capabilities. Vertical vacuum IQ furnaces give heat treaters a larger working zone for efficient and rapid quenching. This article describes the elements of a vacuum IQ furnace line and describes its operational workflow and process control.

Annealing and normalizing both involve heating metal to a temperature and cooling back to room temperature and are differentiated by the metals involved and rate of cooling. This article is an overview of annealing and normalizing processes.

This article compares heat treat processes and furnace types that are typically used to harden gears.

Blaze is an environmentally friendly case-hardening process with good wear characteristics, a low coefficient of friction, and it can be applied directly at the OEM.

This article describes sample preparation to create a visually impressive micrograph image of single-phase cartridge brass, C26000, an alloy composition of 70% copper and 30% zinc. C26000 was chosen due to the striking twins and large grain size that are easily generated by annealing a cold-worked sample, the large range of contrast and colors that can be created by etching, and the wide availability of the material. This entry won the Jacquet-Lucas Award for Best in Show at the 2021 International Metallographic Contest.

Plasma nitriding is very effective in removing the passive layer of chromium oxide formed naturally on the surface of stainless steel, but controlling the kinetics is key for optimal results.

Three types of thermal treating processes are commonly applied to magnesium alloys, including annealing, solution heat treatment, and precipitation, or aging.

The second article in this series looks at materials testing, microstructural evaluation, mechanical testing, and residual stress and distortion using the DANTE Controlled Gas Quenching process.

This study looks at whether adding an annealing step to the heat treating process has an effect on residual stress and distortion on hypoid gear sets. Test results indicate that the annealing heat treatment introduced between gear set soft cutting and case carburizing helped to minimize distortion.

A new method to control distortion in difficult-to-quench geometries addresses the nonuniform cooling inherent in most gas quenching processes. This article describes the development of a controlled gas quenching prototype unit design and its operation. The prototype unit constructed was able to achieve great control within the temperature range of 400 to 100°C, using varying rates of temperature change.

A microscope using differential interference contrast inspects grains and inclusions on heat treated aluminum parts to help predict the performance of the metal.

Using advanced characterization techniques on surface hardened steels builds a richer understanding of the underlying metallurgical phenomena.

Precise controls are at the heart of today’s flame hardening processes and design, delivering consistent, measured, and accurate heat treatments.