Structure and properties of cast rapidly cooled high-speed steel R6M5

Special features of the structure and properties of cast high-speed steel R6M5 cooled from a solid-liquid condition at various rates are considered. Liquid metal is cast into a permanent graphite mold heated to 20, 300, and 600degreesC and cooled in open air or in liquid nitrogen. It is shown that with increase in the cooling rate the degree of alloying of the solid solution and the amount, morphology, and distribution of the carbide component of the steel vary during the crystallization. The parameters of the structure are shown to depend on the properties of the metal (hardness, strength, impact toughness, heat resistance, and wear resistance). Results of wear tests of cast metal-cutting tools are presented.