Because of its speed and ease of control, induction heating can be readily automated and integrated with other processing steps such as forming, quenching, and joining. Completely automated heating/handling/control systems have been developed and are offered by induction equipment manufacturers. This chapter deals with materials handling and automation. First, it summarizes basic considerations such as generic system designs, fixture materials, and special electrical problems to be avoided. Next, it describes and provides examples of materials-handling systems in induction billet heating, bar heating, heat treatment, soldering, brazing, and other induction-based processes. The final section discusses the use of robots for parts handling in induction heating systems.

An induction heating system consists of a source of alternating current (ac), an induction coil, and the workpiece to be heated. This chapter describes the basic phenomena underlying induction heating with respect to the interactions between the coil and the workpiece. The chapter reviews the mechanistic basis for induction heating and provides an example of eddy-current distribution in a solid bar. The chapter defines two important concepts in the technology of induction heating: equivalent resistance and electrical efficiency. The chapter concludes with a discussion of methods for determination of power requirements for a given application.

This chapter explains how to recognize decarburization and related defects. It includes images showing how decarburization appears in various steels, discusses stock removal practices, and describes common defects and flaws such as quench cracks and where they are typically found.

The detailed heating requirements for specific applications must be considered before construction and implementation of any induction heating process. These requirements may include considerations such as type of heating, throughput and heating time, workpiece material, peak temperature, and so forth. The major applications of induction technology include through heating, surface heating (for surface heat treatment), metal melting, welding, brazing, and soldering. This chapter summarizes the selection of equipment and related design considerations for these applications.

This appendix is a glossary of terms related to induction heat treating.

Induction heat treating is used in a wide range of applications. Typical uses, as described in this chapter, include the surface hardening of many types of shafts as well as gears and sprockets and the through-hardening of gripping teeth, cutting edges, and impact zones incorporated into various types of tools and track pins manufactured for off-highway equipment.

This chapter provides a brief review of the scientific and technological developments leading to the widespread use of induction heat treating and its many applications in industry.

Electromagnetic induction, or simply "induction," is a method of heating electrically conductive materials such as metals. It is commonly used for heating workpieces prior to metalworking and in heat treating, welding, and melting. This technique also lends itself to various other applications involving packaging and curing of resins and coatings. This chapter provides a brief review of the history of induction heating and discusses its applications and advantages.

This chapter discusses the basic principles of induction heating and related engineering considerations. It describes the design and operation of induction coils, the magnitude and distribution of magnetic fields, and the forces that generate eddy currents in metals. It explains how induced electrical current causes metal to heat in proportion to their electrical resistance and how it affects temperature dependent properties such as resistivity and specific heat and, in turn, heating rates and efficiencies. It also discusses the effect of hysteresis and explains why eddy currents tend to be confined to the outer surface of the workpiece, a phenomenon known as the skin effect. The chapter includes several data plots showing how the depth of heating varies with frequency and how heating time, power density, and thermal conduction rate correspond with hardening depth.

This chapters discusses the considerations involved in the qualification and analysis of induction hardening treatments. The discussion covers material selection and prior heat treatment, hardness and case depth, frequency selection, power density and heating time, part and process tolerances, geometrical effects, quenchant selection, coil design, and work-handling equipment. The chapter also presents several examples, walking readers though each step, and discusses the development of setup instructions and operating procedures.

This chapter covers the fundamentals of heat treating. It begins with a review of the composition, classification, and properties of iron and steel, the phases of the iron-carbon system, and the basic types of heat treatments. It then discusses the topics of hardness and hardenability, the role of carbon in the hardening of steels, the process of austenitization, and the influence of cooling rate on subsequent transformations. The chapter also explains how induction heating affects residual stress, distortion, and grain size.

This appendix discusses in brief the sources of decarburization of steels as well as the effect of heat treatment on the process.