The Use of Cryogenic Thermal Treatments to Increase the Fracture Toughness of a Hot Work Tool Steel Used to Make Forging Dies

The use of cryogenic heat treatments is not nowadays common in the manufacture of forging dies and other kind of tools though it has been recognized that they can reduce or eliminate retained austenite and also promote the formation of very small carbides, improving the general mechanical properties of the steels.The hardness, strength and the fracture toughness of an H13 tool steel submitted to different heat treatments, including cryogenic ones, were evaluated in this research work and the obtained results were explained based on microstructure modifications (carbide size and distribution, retained austenite, etc.) and differences on the operative fracture micromechanisms.