Common Grades of Tool Steels

Tool steels are primarily used to make tools used in manufacturing and in trade professions to work and form metals, wood, plastics, and other industrial materials. Tools must withstand high specific loads – often concentrated at exposed areas. In addition, they may have to operate at elevated or rapidly changing temperatures, be in continual contact with abrasive types of work materials, be subjected to frequent shocks, or perform under other varieties of adverse conditions. Nevertheless, when employed under circumstances that are regarded as normal operating conditions, the tool should not suffer major damage, untimely wear resulting in the dulling of the edges, or be susceptible to detrimental metallurgical changes.

Tools for less demanding uses, such as ordinary hand tools, including hammers, chisels, files, mining bits, etc., are often made of standard AISI steels that are not considered as belonging to any of the tool steel categories. The steel for most types of tools must be used in a heat‑treated state, hardened and tempered, to provide the properties needed for a particular application. Tool steels must also be adaptable to heat treatment with a minimum of harmful effects while maintaining beneficial changes in material properties.

To meet such varied requirements, steel types of different chemical composition, often produced by special metallurgical processes, have been developed. Due to the large number of tool steel types produced by steel mills, under their own proprietary designations, it can be difficult for the user to select those types that are most suitable for any specific application, unless the recommendations of a particular steel producer or producers are obtained.