Effect of tempering temperature on microstructure and mechanical properties of 42CrMo steel

doi:10.13251/j.issn.0254-6051.2021.01.006

Abstract

Abstract: Through microstructure observation and mechanical properties test,the changes of microstructure and mechanical properties of 42CrMo steel at different tempering temperatures were analyzed.The distribution of elements in the 42CrMo steel tempered at 500 ℃ was analyzed by 3DAP technology,and the influence of Cr,Mn,Mo,etc.on the steel properties was studied.The results show that the microstructure of the steel is tempered troostite when tempered at 450 ℃ after water quenching.In the tempering range of 500-650 ℃,the microstructure are tempered sorbite.With the increase of tempering temperature,granular carbides increase,the tensile strength and the specified plastic elongation strength decrease,and the -40 ℃ low temperature impact performance increases.Tempering at 500 ℃ can reach the mechanical index of grade 12.9 bolts (R_m≥1200 MPa,KV₂≥27 J) and obtain the best mechanical properties,and meet the requirements of bolt steel in low temperature environments.The 3DAP results show that the alloying elements in the steel improve the performance of steel through solid solution strengthening and precipitation strengthening.

Key words: 42CrMo steel, tempering temperature, mechanical properties, microstructure, 3DAP

CLC Number:

TG142

Lü Chaoran, Shi Chao, Jiang Weibin, Liu Jinde, Xu Le, Wang Maoqiu. Effect of tempering temperature on microstructure and mechanical properties of 42CrMo steel[J]. Heat Treatment of Metals, 2021, 46(1): 32-37.

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