Effect of Co on microstructure and strength and toughness of 4Cr5Mo2V steel

doi:10.13251/j.issn.0254-6051.2021.11.008

Abstract

Abstract: Effect of Co on microstructure, strength and toughness of the 4Cr5Mo2V steel was studied by means of OM, SEM, EDS, hardness test, room temperature impact and high temperature tensile tests. The results show that the 4Co5Mo2V-Co steel has more undissolved carbides and the martensite laths are thinner after quenching at 1010 ℃ for 30 min. When tempered at 510-600 ℃, the hardness of the 4Co5Mo2V-Co steel is 1-2 HRC higher than that of the 4Co5Mo2V steel, while the two steels have similar impact properties. The 4Cr5Mo2V-Co steel has higher high-temperature strength under the same initial hardness, which is because the addition of Co promotes the nucleation rate of secondary hardened carbides in the 4Cr5Mo2V-Co steel, and reduces the coarsening rate of carbides, thereby improving the strength of the 4Cr5Mo2V-Co steel.

Key words: heat treatment, hot work die steel, mechanical properties, solid solution strengthening

CLC Number:

TG113.25

Deng Junjie, Zhou Jian, Liu Jianxiong, Chi Hongxiao, Fan Yi. Effect of Co on microstructure and strength and toughness of 4Cr5Mo2V steel[J]. Heat Treatment of Metals, 2021, 46(11): 48-53.

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