Conclusion
Tool steels- Chemical composition and structure

Tool steels are a family of materials whose chemical composition generally consists of a fairly high carbon content, combined with "carburigenic" alloying elements such as molybdenum, tungsten, vanadium and chromium. The high hardness obtained after quenching and tempering is the result of obtaining a structure that is generally martensitic, and in most cases strengthened by the precipitation of secondary carbides. Cobalt can be added to improve hot hardness, and nickel to enhance impact resistance and quench penetration. Many grades have a greater or lesser quantity of primary carbides containing vanadium, molybdenum, tungsten and chromium in their microstructure, to enhance wear resistance. The prospects for this class of materials lie in two directions:

• low-carbon grades strengthened by precipitation of intermetallic phases combining the...