This work describes the development of a model to simulate the compound layer growth kinetics for nitriding AISI 4140 steel based on a customized Lehrer diagram. The model can be used to calculate concentration profiles of nitrogen as a function of time and position during the nitriding process and to predict the thickness of the compound layer. Winner of the 2012 HTS-Bodycote Best Paper in Heat Treating Award endowed by Bodycote Thermal Process-North America.

In order to expand the choice of materials available for use in additive manufacturing, parameters that consider welding metallurgy, laser powder interaction, and post processing must be developed. This article describes the outcomes of process development for a steel and stainless steel alloy that are not standard materials for laser powder bed fusion equipment.

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.

The Center for Heat Treating Excellence (CHTE) was founded with the goal of bringing the industrial sector and university researchers together to find solutions to real-world problems. The Center, located at Worcester Polytechnic Institute (WPI) in Massachusetts, has 19 members from all areas of industry working together with WPI researchers to improve both heat treat and thermal processing methods worldwide. This article describes some of the current CHTE research projects.

New methods evaluate steel hardenability in a standard gas quench test and heat transfer coefficient variation within a furnace gas quench chamber.

Proper specification, measurement, and control of annealing furnace atmospheres are critical to reduce sooting, oxidation, sticking, and distortion. This article describes how to effectively design and utilize a nitrogen-hydrogen annealing atmosphere.

Boriding is performed by diffusing boron atoms into a metal surface and allowing the boron to react with elements present in the substrate to form metal-boride compounds. Upon diffusing enough boron into the surface, a metal-boride compound layer with high hardness precipitates and grows below the surface of the part. This article discusses boriding of ferrous alloys, including a new deep case boriding method that produces wear layer depths comparable to competitive processes such as carburizing, nitriding, thermal spray coatings, and hardfacing.

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

Computer modeling is used in the design and development stages of induction hardening to optimize the process and to improve component quality including hardness, beneficial stress distributions, and reduced distortion.

Intensive quenching enables manufacturers to improve part performance at a lower cost than other available methods. This article describes how using direct-from-forge intensive quenching can significantly reduce the cost of manufacturing steel products when engineered into the lean part-making process.

Throughout metal making history, nothing has exceeded the technical importance, scientific complexity, and human curiosity involved in the hardening of steel. After the bustling 1890s, with its exciting and productive discoveries around steel metallography, a period of quiet consolidation occurred in the early 20th century. This article describes the breakthroughs in steel metallurgy that occurred after this period by such pioneers as William Chandler Roberts-Austen, Adolf Martens, Henry Marion Howe, and Edgar C. Bain.

Flash processing, a new heat treatment for steels based on the concept of rapid thermal cycling, has been shown to achieve new levels of strength and ductility. This article describes the process, its effects on microstructure, and the phase transformations involved. It also discusses current and potential future applications.

Modern, high quality induction heat treating equipment must be readily available and flexible enough to allow for easy retooling and reprogramming to process a variety of parts. This article focuses on the technical revolution taking place in induction heating, which for the first time enables preprogramming of induction equipment to change frequency and power during the heating cycle in the same manner manner as machinists have been programming CNC machines for years. This is illustrated through a case study of induction hardening a shaft-like component.

Automotive die OEMs throughout Europe are using laser heat treatment (LHT) to deliver parts fast, with superior quality, at lower cost. This article presents a basic technical introduction to LHT and the results of a case study of LHT cost savings in automotive trim/form dies.

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.

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.