Effect of Magnesium Treatment on Microstructure and Properties after Quenching and Tempering Industrial H13 Steel

Abstract

The effect of magnesium treatment on the microstructure and mechanical properties of industrial H13 steel after quenching and tempering. The impact toughness and tensile tests were mainly carried out, and the microstructure was performed by SEM, EBSD, and X-ray diffraction. The results show that magnesium treatment is still feasible in industrial trials. It is mainly manifested in the refinement of lath martensite and carbides. Compared with calcium treatment, the prior austenite grains and carbides size of industrial H13 steel treated with magnesium decreased after quenching. And the second phase particles of VC carbides in Mg treatment obviously spheroidized and distributed uniformly and increased in quantity significantly after quenching and tempering. Moreover, the impact toughness, yield strength, and ultimate tensile strength of industrial H13 steel with magnesium treatment increase by 28%,65.5Mpa, and 123.7 MPa respectively. The increment of strength mainly comes from dislocation strengthening, grain refinement strengthening, and precipitation strengthening, among which precipitation strengthening accounts for the largest proportion.

Keywords: industrial H13 die steel, Mg treatment, Heat treatment, carbide