贝氏体等温淬火对H13热作模具钢组织及热疲劳性能的影响

Effect of bainite isothermal quenching on microstructure and thermal fatigue performance of H13 hot working die steel

采用光学显微镜、扫描电镜和热疲劳试验等研究了常规淬火和等温淬火两种不同工艺对H13钢显微组织和热疲劳性能的影响。结果表明:等温淬火处理后H13钢的显微组织为马氏体+下贝氏体(M/B下)。与常规淬火相比,具有M/B下复相组织的试验钢的硬度有所降低,冲击韧性有所提高。热疲劳裂纹分析表明,经等温淬火处理后试样的热疲劳裂纹在长度和密度上均小于常规淬火处理的试样,表明M/B下复相组织有益于提高H13钢的热疲劳性能。

Effect of conventional quenching and isothermal quenching on microstructure and thermal fatigue properties of H13 steel was studied by means of optical microscope, scanning electron microscopy and thermal fatigue test. The results show that the microstructure of the H13 steel after isothermal quenching is martensite and lower bainite(M/BL). Compared with conventional quenching, the hardness of the experimental steel with martensite and lower bainite(M/BL) complex microstructure decreases slightly, and the impact toughness increases slightly. The thermal fatigue crack analysis shows that the thermal fatigue crack of the sample after isothermal quenching is smaller in length and density than that of the sample treated by conventional quenching, which indicates that the(M/BL) complex microstructure is beneficial to improve the thermal fatigue performance of the H13 steel.