Tool steels refers to a variety of carbon and alloy steels that are particularly well-suited to be made into tools. Their suitability comes from their distinctive hardness, resistance to abrasion and deformation and their ability to hold a cutting edge at elevated temperatures. As a result tool steels are suited for their use in the shaping of other materials.

There are six groups of tool steel:

  1. water-hardening tool steels,
  2. cold-work tool steels,
  3. shock-resisting tool steels,
  4. high-speed tool steels,
  5. hot-work tool steels,
  6. special purpose/plastic mold tools steels.

You have full details of six groups tool steel here: What Is Tool Steel ? (Six Groups With Details)