Search Results for medium-alloy cold-work tool steel

Tool steels represent a small, but very important, segment of the total production of steel. Their principal use is for tools and dies that are used in the manufacture of commodities. For the most part, the processes used for heat treating carbon and alloy steels are also used for heat treating tool steels, that is, annealing, austenitizing, tempering, and so forth. This chapter focuses on these heat treating processes of tool steels. Classification and approximate compositions and heating treating practices of some principal types of tool steels are provided. The steel types discussed include water-hardening; shock-resisting; oil-hardening cold-work; air-hardening, medium-alloy cold-work; high-carbon, high-chromium cold-work; low-alloy, special-purpose; mold; hot-work; and high-speed tool 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 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.

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.

The possible classification for tool steels is their division into four groups according to their final application: hot-worked, cold-worked, plastic mold, and high-speed tool steels. This chapter mainly follows such division by application, but the grade nomenclatures used here are primarily from AISI. It presents the classification of tool steels and discusses the principles and processes of tool steel heat treating, namely normalizing, annealing, hardening, and tempering. Various factors associated with distortion in several tool steels are also covered. The chapter discusses the composition, classification, and properties of unalloyed and low-alloy cold-worked tool steels; medium and high-alloy cold-worked tool steels; and 18% nickel maraging steels.

Tools steels are defined by their wear resistance, hardness, and durability which, in large part, is achieve by the presence of carbide-forming alloys such as chromium, molybdenum, tungsten, and vanadium. This chapter describes the alloying principles employed in various tool steels, including high-speed, water-hardening, shock-resistant, and hot and cold work tool steels. It discusses the influence of alloy design on the evolution of microstructure and properties during solidification, heat treating, and hardening operations. It also describes critical phase transformations and the effects of partitioning, precipitation, segregation, and retained austenite.

The air-hardening cold-work tool steels, designated as group A steels in the AISI classification system, achieve their processing and performance characteristics with combinations of high carbon and moderately high alloy content. This chapter describes the microstructural features and hardenability of air-hardening cold-work tool steels and discusses the processes involved in the hardening and tempering of tool steels.

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.

The oil-hardening cold-work tool steels, designated as group O steels in the AISI classification system, derive their high hardness and wear resistance from high carbon and modest alloy contents. This chapter describes the microstructures and hardenability of oil-hardening tool steels and discusses the processes involved in the hardening and tempering of tool steels. It also covers the selection criteria and applications of oil-hardening cold-work tool steels.

The high-carbon, high-chromium tool steels, designated as group D steels in the AISI classification system, are the most highly alloyed cold-work steels. This chapter describes the microstructures and hardenability of high-carbon, high-chromium tool steels and discusses the processes involved in the hardening and tempering of tool steels. It also covers the selection criteria and applications of high-carbon, high-chromium tool steels.

This article provides an overview of tool steels, discussing their composition, properties, and behaviors. It covers all types and classes of wrought and powder metal tool steels, including high-speed steels, hot and cold-work steels, shock-resisting steels, and mold steels. It explains how the properties of these steels are determined by alloying elements, such as tungsten, molybdenum, vanadium, manganese, and chromium, and the presence of alloy carbides. It describes the types of carbides that form and how they contribute to wear resistance, toughness, high-temperature strength, and other properties.

This chapter describes the processes involved in the fabrication of wrought and cast metal products. It discusses deformation processes including bending and forming, material removal processes such as milling, cutting, and grinding, and joining methods including welding, soldering, and brazing. It also discusses powder consolidation, rolling, drawing and extrusion, and common forging methods.

Tool steels are a special class of alloys designed for tool and die applications. High-speed steels are a subset of tool steels designed to operate at high speeds. This chapter describes the composition, properties, heat treatment, and use of wrought and alloyed tool steels, high-speed steels, and their counterparts made by powder metallurgy. It includes information on the chemical composition and application range of many commercial tool steels and explains how to apply coatings that reduce friction, thermal conductivity, and wear.

This chapter focuses on the failure aspects of tool steels. The discussion covers the classification, chemical composition, main characteristics, and several failures of tool steels and their relation to heat treatment. The tool steels covered are hot work, cold work, plastic mold, and high-speed tool steels.

This chapter describes the equipment and processes used to form titanium alloy parts. It discusses the advantages and disadvantages of hot and cold forming, the factors that influence formability, and the effect of forming temperature and lubricants. It describes common processes, including brake forming, stretch forming, deep drawing, and spin forming as well as roll forming, drop-hammer forming, tube bulging and bending, and superplastic forming. It also discusses dimpling and joggling and the use of hot sizing to correct springback.

This chapter discusses the types, methods, and advantages of heat treating procedures, including annealing, normalizing, tempering, and case hardening. It describes the iron-carbon system, the formation of equilibrium and metastable phases, and the effect of alloy elements on hardenability and tempering response. It discusses the significance of critical temperatures, the use of transformation diagrams, and types of annealing treatments. It also provides information on heat treating furnaces, the effect of heating rate on transformation temperatures, quench and temper procedures, and the use of cold treating.

Steels for hot-work applications, designated as group H steels in the AISI classification system, have the capacity to resist softening during long or repeated exposures to high temperatures needed to hot work or die cast other materials. These steels are subdivided into three classes according to the alloying approach: chromium hot-work steels, tungsten hot-work steels, and molybdenum hot-work steels. This chapter discusses the composition, characteristics, applications, advantages, and disadvantages of each of these steels.

This appendix is a collection of tables listing coefficients of linear thermal expansion for carbon and low-alloy steels, presenting a summary of thermal expansion, thermal conductivity, and heat capacity; and listing thermal conductivities and specific heats of carbon and low-alloy steels.

Metal removal processes for gear manufacture can be grouped into two general categories: rough machining (or gear cutting) and finishing (or high-precision machining). This chapter discusses the processes involved in machining for bevel and other gears. The chapter describes the type of gear as the major variable and discusses the machining methods best suited to specific conditions. Next, the chapter provides information on gear cutter material and nominal speeds and feeds for gear hobbing. Further, it describes the cutting fluids recommended for gear cutting and presents a comparison of steels for gear cutting. The operating principles of computer numerical control and hobbing machines are also covered. This is followed by sections that discuss the processes involved in grinding, honing, and lapping of gears. Finally, the chapter provides information on the superfinishing of gears.

The appendix provides a glossary of practical heat treating terms.