低温回火时间对GCr15钢组织演变与力学性能的影响

Effect of low temperature tempering time on microstructure evolution and mechanical properties of GCr15 steel

采用扫描电镜(SEM)、能量色散光谱仪(EDS)、电子背散射衍射(EBSD)技术、X射线衍射(XRD)、万能试验机、洛氏硬度计等研究了低温回火时间对GCr15钢显微组织和力学性能的影响。结果表明:随着回火时间的增加,GCr15钢中碳化物面积分数不断增加,其平均直径先增加后减小;回火态与淬火态的碳化物类型主要为M7C3和M23C6;随着回火时间的增加,试验钢的回火马氏体逐渐分解消失,组织形态有显著变化,但其尺寸变化不大,抗拉强度逐渐升高,但硬度有一定程度降低。

Effect of low temperature tempering time on microstructure and mechanical properties of GCr15 steel was investigated by means of scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS) analysis, electron backscatter diffraction(EBSD) technology, X-ray diffraction(XRD), universal testing machine and Rockwell hardness tester. The results show that with the increase of tempering time, the area fraction of carbides of the GCr15 steel increases, and the average diameter of the carbides increases first and then decreases. The main types of carbides of the GCr15 steel after tempering and quenching are M7C3 and M23C6, respectively. With the increase of tempering time, the tempered martensite of the GCr15 steel gradually decomposes and disappears, which leads to the significant changes of microstructure morphology, but its size does not change much, and the tensile strength of the GCr15 steel gradually increases, but the hardness decreases slightly.