A variety of existing methods for modifying the surface of tool materials can be divided into four groups: surface heat treatment; chemical-thermal
treatment; coating synthesis; combined hardening. Heat treatment leads to a change in the structure of the material and an improvement in surface properties without a significant change in the chemical composition. Chemical-thermal treatment to a greater extent leads to changes in the chemical composition, structure and properties of the surface. The coating makes it possible to obtain materials with a new chemical
composition and surface structure, which provides a strong change in properties. Combined hardening is a kind of superposition of the above methods.