淬火温度对5Cr15MoV钢空冷淬火组织与性能的影响

Effect of quenching temperature on microstructure and properties of 5Cr15MoV steel by air-cooling quenching

通过1000~1200℃间隔50℃的系列加热温度对5Cr15MoV马氏体不锈钢进行空冷淬火试验,并采用光学显微镜、EBSD和洛氏硬度计对不同温度淬火后组织和硬度进行检测,研究了淬火温度对试验钢组织、晶粒尺寸、残留奥氏体含量以及硬度的影响。结果表明,试验钢淬火后组织为马氏体+未溶合金碳化物+残留奥氏体。随着淬火温度升高,马氏体板条尺寸增大,未溶碳化物量逐渐减少直至消失,残留奥氏体含量先增加后减少。试验钢的硬度变化趋势为先增加后显著降低,在淬火温度为1050℃达到最大值60.8 HRC。试验钢硬度主要是马氏体的含碳量、晶粒尺寸、残留奥氏体含量和碳化物含量综合作用的结果。

Air cooling quenching experiment was performed on 5 Cr15 MoV martensitic stainless steel at a series of heating temperatures ranging from 1000 ℃ to 1200 ℃ at an interval of 50 ℃. The test of microstructure and hardness were performed by means of optical microscope, EBSD and Rockwell hardness tester after quenching at different temperatures. The effect of quenching temperature on microstructure, grain size, retained austenite content and hardness of the tested steel was studied. The results show that the quenched steel consists of martensite, undissolved carbide and retained austenite. With the increase of quenching temperature, the size of martensitic lath increases, the amount of undissolved carbide decreases gradually until it disappears, and the content of retained austenite increases first and then decreases. The hardness of the tested steel increases first and then decreases significantly, and reaches the maximum of 60.8 HRC at 1050 ℃. The hardness of the tested steel is mainly the result of comprehensive effect of carbon content of martensite, grain size, retained austenite content and carbide content.