The nitriding process can be applied to various materials and part geometries. This chapter focuses on tool steels, pure irons, low-alloy steels, and maraging steels. Various considerations such as the surface metallurgy requirements of the die, including case depth, compound layer formation, and temperature, are also discussed in this chapter. The chapter also addresses steel selection and surface metallurgy of gears.

This chapter first lists the compositions of typical steels that are suitable for nitriding. It then presents considerations for steel selection. The chapter also shows the influence of alloying elements on hardness after nitriding and the depth of nitriding. It provides a detailed discussion on plasma nitriding of type 422 stainless steel, nitriding of type 440A and type 630 (17-4 PH) stainless steel. The chapter also discusses plasma nitride case depths.

This chapter discusses the factors that affect die steel selection for hot forging, including material properties such as hardenability, heat and wear resistance, toughness, and resistance to plastic deformation and mechanical fatigue. It then describes the relative merits of various materials and the basic requirements for cold forging dies. The chapter also covers die manufacturing processes, such as high-speed and hard machining, electrodischarge machining, and hobbing, and the use of surface treatments.

This appendix is a collection of selected continuous cooling transformation diagrams for carbon steels; Mn steels; Mn-Mo, Mn-Ce, Mn-Ni-Mo, and Mn-Ni-CrMo steels; silicon steels; nickel steels; Ni-Cr-Mo steels; and chromium steels.

The several specific grades or compositions of tool steels have evolved over time and have been organized into useful groupings. This chapter presents the AISI classification system for tool steels, which categorizes tool steels by their alloying, applications, or heat treatment, and briefly describes the characteristics of each major group. It discusses selection criteria for tool steels, along with examples.

This appendix is a collection of isothermal diagrams for carbon steels, chromium-molybdenum steels, nickel-chromium-molybdenum steels, nickel-molybdenum steels, and chromium steels.

This appendix provides tensile property and fracture toughness data for various low-alloy and stainless steels.