Transactions of Materials and Heat Treatment

Title：Influence of heat treatment parameters on microstructure and property of Cr8 cold working die steel

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ClassificationCode：TG142

year,vol(issue):pagenumber：2020,45(1):168-172

Abstract：

For the secondary hardening problem of Cr8 cold working die steel, the influences of low temperature tempering and high temperature tempering on microstructure and property of Cr8 cold working die steel were studied by metallographic microscope, SEM, EDS and Rockwell hardness tester. The result shows that the structure of raw material are pearlite and a small amount of eutectic carbides with the length of 9-41 μm and the width of 2-11 μm, and after tempering at different temperatures, the structures of material are martensite and a small amount of large particle eutectic carbides with the length of 4-25 μm and the width of 1-8 μm as well as small secondary precipitation carbides. When the material is quenched at 1030 ℃ and tempered at 520 ℃, the material shows secondary hardening phenomenon with the hardness of 58.4 HRC, which is 1.4 HRC higher than that at a low temperature of 200 ℃. Furthermore, the secondary hardening of Cr8 steel is caused by the substantial precipitation of secondary nano-sized small particle carbides after tempering at a high temperature of 520 ℃, and the particles are evenly distributed in the matrix.

Funds：

国家重点研发计划项目（2016YFB0300405）

元莎（1990-），女，博士研究生 E-mail：741916485@qq.com 通讯作者：蒋鹏（1964-），男，博士，博士生导师，研究员 E-mail：jp1964@163.com

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