Surface nanocrystallization and mechanical properties of mold steel induced via scanning electron beam treatment

Abstract

Improving the comprehensive mechanical properties of the surface of 5CrNiMo mold steel and prolonging the service life of the mold are important tasks of mold development. Hence, 5CrNiMo mold steel was irradiated by scanning electron beam to improve the property. It is indicated that during the electron beam irradiation process, the carbide nano-grains appeared in material surface, leading to a significant increase in surface microhardness by more than twofold to reach 845.6 HV. Additionally, the wear resistance of the specimen increased 7 times while its wear loss decreased to 0.2 mg from 1.4 mg. The surface roughness of the irradiated sample also decreased from 1.9 μm to 0.9 μm. The relationship between the comprehensive mechanical properties of the surface nanocrystallization is uncovered, which provides a dawn for producing 5CrNiMo mold steel with extraordinary properties.