There is a fairly wide variety of different tool steels for different applications. The American Iron and Steel Institute (AISI) classification of tool steels includes seven major categories: water-hardening tool steels, shock-resisting tool steels, cold work tool steels, hot work tool steels, low-alloy special-purpose tool steels, mold tool steels, high-speed tool steels, and powder metallurgy tool steels. This chapter provides discusses the manufacturing process, composition, properties, types, and applications of these tool steels and other cutting tool materials, such as cemented carbides. It also describes the methods of applying coatings to cutting tools to improve tool life.

High-speed tool steels have in common the ability to maintain high hardness at elevated temperatures. High speed steels are primarily used for cutting tools that generate heat during high-speed machining. They are designated as group M or group T steels in the AISI classification system, depending on whether the major alloying approach is based on molybdenum or tungsten. This chapter describes the effects of each of the alloying elements and carbon content on the processing, microstructures, and properties of high-speed steels. It discusses the processes involved in the solidification, hot work, annealing, austenitizing for hardening, and tempering of high-speed steels. It also discusses the processes involved in controlling grain size during austenitizing and reviews the characteristics of cooling transformations and other property changes in tempered high-speed steels. Information on multipoint cutting tools is provided. The chapter discusses the applications of high-speed tool steel and factors in selecting high-speed tool steels.

The qualities that make superalloys excellent engineering materials also make them difficult to machine. This chapter discusses the challenges involved in machining superalloys and the factors that determine machinability. It addresses material removal rates, cutting tool materials, tool life, and practical issues such as set up time, tool changes, and production scheduling. It describes several machining processes, including turning, boring, planing, trepanning, shaping, broaching, drilling, tapping, thread milling, and grinding. It also provides information on toolholders, fixturing, cutting and grinding fluids, and tooling modifications.

This chapter discusses the factors that influence the cost and complexity of machining titanium alloys. It explains how titanium compares to other metals in terms of cutting force and power requirements and how these forces, along with cutting speeds and the use of cutting fluids, affect tool life, surface finish, and part tolerances. The chapter also includes a brief review of nontraditional machining methods.

This chapter covers the practical aspects of machining, particularly for turning, milling, drilling, and grinding operations. It begins with a discussion on machinability and its impact on quality and cost. It then describes the dimensional and surface finish tolerances that can be achieved through conventional machining methods, the mechanics of chip formation, the factors that affect tool wear, the selection and use of cutting fluids, and the determination of machining parameters based on force and power requirements. It also includes information on nontraditional machining processes such as electrical discharge, abrasive jet, and hydrodynamic machining, laser and electron beam machining, ultrasonic impact grinding, and electrical discharge wire cutting.

This article discusses the applications, compositions, and properties of cemented carbides and cermets. It explains how alloying elements, grain size, and binder content influence the properties and behaviors of cemented carbides. It also discusses the properties of steel-bonded carbides, or cermets, the various grades available, and the types of applications for which they are suited.

Beryllium’s machining characteristics are similar to those of heat-treated cast aluminum and chilled cast iron. Like the other materials, it can be turned, milled, drilled, bored, sawed, cut, threaded, tapped, and trepanned with good results. This chapter explains how these machining operations are conducted and describes the effect of tooling materials, cutting speeds, metal-removal rates, and other variables. It also explains how to assess and remove surface damage caused by machining such as microcracks and twins.

This chapter focuses on the metallurgical factors governing the machinability of stainless steels. It begins by describing the chemistry, cleanliness, structure, processing history, and the cross-section size of the stock of the different grades of stainless steel. This is followed by a general description of the machining behavior of the stainless steel families, namely ferritic, martensitic, austenitic, precipitation hardening, duplex, and super stainless steels. The beneficial effect of controlled inclusions is then discussed. The chapter ends with a section providing information on high-speed tool steel and carbide tooling, along with tool coatings and coolants applicable to stainless steel.