This article discusses the characteristics, composition limits, and classification of wrought tool steels, namely high-speed steels, hot-work steels, cold-work steels, shock-resisting steels, low-alloy special-purpose steels, mold steels, water-hardening steels, powder metallurgy tool steels, and precision-cast tool steels. It describes the effects of surface treatments on the basic properties of tool steels, including hardness, resistance to wear, deformation, and toughness. The article provides information on fabrication characteristics of tool steels, including machinability, grindability, weldability, and hardenability, and presents a short note on machining allowances.

Tool steels are any steel used to make tools for cutting, forming, or shaping manufactured parts. Most tool steels are wrought products alloyed with relatively large amounts of tungsten, molybdenum, vanadium, manganese, and/or chromium. The article describes a wide variety of tool steels, including high-speed steels, hot and cold-work steels, shock-resisting steels, and special-purpose steels. Hot-work steels are designed to withstand excessive amounts of heat, pressure, and abrasion, suiting them for punching, shearing, and high-temperature forming applications. Cold-work tool steels have exceptional dimensional stability and wear resistance, but lack the alloy content necessary to resist softening at temperatures above 205 to 260 deg C. The article examines standard designations for all tool steel types and provides corresponding composition and property ranges. It also discusses surface treatments, fabrication issues, and in-service measures of performance.