Induction heat treatment is a common method for hardening and tempering of crankshafts, which are necessary components in almost every internal combustion engine for cars, trucks, and machinery, as well as pumps, compressors, and other devices. Similar to crankshafts, camshafts also belong to the same group of the critical engine/powertrain components. This article focuses on induction technologies used for surface hardening and tempering of automotive crankshafts, and provides general information on U-shaped inductors with crankshaft rotation and clamshell or split inductors without crankshaft rotation and their pros and cons. It also describes the effect of post-heat-treatment processes in crankshafts. The article concludes with a discussion on induction hardening of camshafts that focuses on those used in automobiles and truck engines.

Induction heat treating is used in the off-road machinery industry for hardening steel and cast iron components used in a wide range of applications. This article focuses on the usage of induction hardening components in the industry, and discusses the basic requirements of steel and cast iron to undergo induction hardening. It provides a comparison on single-shot and scan hardening methods to select the suitable one for induction heat treating of gears and sprockets. The article describes the effect of microstructure, residual stress, and workpiece position on induction hardening. It concludes with a discussion on the important factors to be considered during the installation of off-road machinery components.

Induction hardening of geared parts used in aeronautic and aerospace industry is an important technology because of its one-piece flow, repeatability, energy efficiency, and tighter control of surface distortion than conventional carburizing. This article describes the requirements and characteristics of induction hardening of transmission parts, such as bearings, shafts, and different types of gears, including bevel gears, spur wheel gears, helical gears, and splines. It provides information on process monitoring and the economic aspects of induction hardening.

Induction hardening is a prominent method in the gear manufacturing industry due to its ability of selectively hardening portions of a gear such as the flanks, roots, and/or tips of teeth with desired hardness, wearing resistance, and contact fatigue strength without affecting the metallurgy of the core. This article provides an overview of gear technology and materials selection. It describes different gear-hardening patterns, namely, tooth-by-tooth hardening, tip-by-tip hardening, gap-by-gap hardening, spin hardening, single-frequency gear hardening, dual-frequency gear hardening, simultaneous dual-frequency gear hardening, and through heating for surface hardening. It provides information on the different inspection methods based on the American Gear Manufacturers Association, revealing metallurgical data, hardness, and dimensions of gears. In addition, the article presents a comparative study on the mechanical properties of contour-hardened and carburized gears. It concludes by describing typical failures of induction-hardened steels and the corresponding prevention methods.

This article focuses on induction hardening process for heat treating operations specifically designed to result in proper microstructure/property combinations in either localized or in the final parts. It briefly reviews the heat treating basics for conventional heat treating operations of steels with iron-carbon phase and transformation diagrams. The article provides a summary of the important temperatures, definitions, and microstructural constituents associated with heat-treated steels. Basic transformation characteristics of heat-treated steels are reviewed. The article also discusses the various aspects of steel heat treatment by induction processing, and concludes with a description of steel alloys for induction processing.

Induction hardening of steel components is the most common application of induction heat treatment of steel. This article provides a detailed account of electromagnetic and thermal aspects of metallurgy of induction hardening of steels. It describes induction hardening techniques, namely, scan hardening, progressive hardening, single-shot hardening, and static hardening. The article discusses the techniques used to control the heat pattern, and provides a brief review of quenching techniques used in the induction hardening. It provides guidelines for selecting the frequency and power for induction hardening, and describes common methods for measuring case depth, such as optical and microhardness, and surface hardness. It provides information on some complications and ambiguities associated with these measurements. The article also discusses the commonly used non-destructive testing methods, namely, magnetic particle testing, ultrasonic testing, and eddy current testing to evaluate induction-hardened components.

This article describes the common types of automotive and truck axle shafts. It provides information on steels used for induction-hardened shafts, and on the manufacturing and induction hardening methods of axle shafts. The article discusses the effects of case depth, shaft length, and carbon content on torsional properties of axle shafts, and the effect of changes in shaft diameter and those of splines on torsional shaft performance. It also provides useful information on straightening and tempering of induction-hardened axle shafts, and describes an effective technique to ensure quality of induction-hardened axle shafts.