Temperature is a critical process parameter in the heat treatment and forging of steel and must be accurately measured to properly control it. This appendix discusses the operating principles of thermocouples and infrared pyrometers, describing the various types as well as advantages and applications.

This chapter discusses the selection, use, and integration of methods to control process variables in induction heating, including control of workpiece and processing temperature and materials handling systems. The discussion of temperature control includes a review of proportional controllers and heat-regulating devices. Integration of control functions is illustrated with examples related to heating of steel slabs, surface hardening of steel parts, vacuum induction melting for casting operations, and process optimization for electric-demand control. Distributed control within larger manufacturing systems is discussed. The chapter also covers nondestructive techniques for process control and methods for process simulation.

This chapter discusses the basic components in an induction heat treating system. It describes the design and operating characteristics of power supplies, load-matching transformers, tuning capacitors, power regulators, controllers, process monitors, and diagnostic systems. It also provides information on fixtures and work-handling devices, quench systems, and load matching and tuning procedures.

The temperature and atmosphere conditions must be precisely controlled in order to achieve the desired metallurgical results during heat treating operations. In order to ensure the repeatability of operation, a heat treating system must have the necessary sensors, timers, and variable (temperature, atmosphere, etc.) controllers to hold the process within prescribed or specified limits. This chapter discusses temperature and atmosphere sensors used in a heat treating system. The temperature sensors covered are contact and noncontact types. The atmosphere sensors covered are oxygen probe, dew point, and infrared. The chapter concludes with an overview of the development of integrated control systems.

This chapter provides an overview of the thermodynamics of extrusion. It begins by presenting a thermodynamic model of the extrusion process expressed in the form of finite difference equations. It then explains how the model accounts for multiple sources of heat generation, the influence of principal variables on temperature rise, and different types of temperature measurements. It also discusses the benefits of isothermal extrusion and how it achieves consistent mechanical properties in extruded components.

Besides the induction coil and workpiece, the induction generator (source of ac power) is probably the most important component of an overall induction heating system. Such equipment is typically rated in terms of its frequency and maximum output power (in kilowatts). This chapter addresses the selection of power supplies in terms of these two factors as well as the operational features of different types of sources. The six different types of power supplies for induction heating applications covered in this chapter are line-frequency supplies, frequency multipliers, motor-generators, solid-state (static) inverters, spark-gap converters, and radio-frequency power supplies. The chapter discusses the design and characteristics of each of the various types of power supplies.

Induction heating has found widespread use as a method to raise the temperature of a metal prior to forming or joining, or to change its metallurgical structure. However, induction heating has specialized capabilities that make it suitable for applications outside of metal treatment and fabrication. This chapter summarizes some of the special applications of induction heating, including those in the plastics, packaging, electronics, glass, chemical, and metal-finishing industries. The chapter concludes with a discussion of the application of induction heating for vacuum processes.

This chapter focuses on short-term tensile testing at high temperatures. It emphasizes one of the most important reasons for conducting hot tensile tests: the determination of the hot working characteristics of metallic materials. Two types of hot tensile tests are discussed in this chapter, namely, the Gleeble test and the conventional isothermal hot-tensile test. The discussion covers equipment used and testing procedures for the Gleeble test along with information on hot ductility and strength data from this test. The chapter describes the stress-strain curves, material coefficients, and flow behavior determined in the isothermal hot tensile test. It also describes three often-overlapping stages of cavitation during tensile deformation, namely, cavity nucleation, growth of individual cavities, and cavity coalescence.

After shaping and first-stage binder removal, the component (with remaining backbone binder) is heated to the sintering temperature. Further heating induces densification, evident as dimensional shrinkage, pore rounding, and improved strength. This chapter begins with a discussion on the events that are contributing to sintering densification, followed by a discussion on the driving forces, such as surface energy, and high-temperature atomic motion as well as the factors affecting these processes. The process of microstructure evolution in sintering is then described, followed by a discussion on the tools used for measuring bulk properties to monitor sintering and density. The effects of key parameters, such as particle size, oxygen content, sintering atmosphere, and peak temperature, on the sintered properties are discussed. Further, the chapter covers sintering cycles and sintering practices adopted as well as provides information on dimensional control and related concerns of sintering. Cost issues associated with sintering are finally covered.

This chapter presents a glossary of foundry terms.

This chapter discusses the composition and classification of stainless steels and focuses on the processes involved in heat treatment and applications of these steels. The wrought and the cast stainless steels covered are ferritic, austenitic, duplex (ferritic-austenitic), martensitic, and precipitation-hardening. In addition, information on special considerations for stainless steel castings is also provided. The heat treatment processes explained in the chapter are preheating, annealing, stress relieving, hardening, tempering, austenite conditioning, heat aging, and nitride surface hardening. Finally, some special considerations for stainless steel castings are discussed.

Induction heating, in most applications, is used to selectively heat only a portion of the workpiece that requires treatment. This chapter covers the basic principles, features, and metallurgical aspects of induction heating. The discussion includes the conditions required for induction heating and quenching, the use of magnetic flux concentrators to improve the efficiency of surface heating, and the quenching systems used for induction hardening. The discussion also provides information on time-temperature dependence in induction heating, workpiece distortion in induction surface hardening, residual stresses after induction surface hardening and finish grinding, and input and output control of steel for induction surface hardening of gears.

This appendix is a compilation of terms and definitions related to metallurgy.