42CrMo钢泵筒内壁激光相变硬化组织模拟

采用有限元软件SYSWELD建立三维模型,考虑相变潜热及材料热物理性能随温度的变化,将温度场和相变模型进行耦合,对泵筒内壁激光相变硬化组织转变过程及硬度分布进行数值模拟。结果表明:激光相变硬化是一个快速加热和冷却的过程;在加热过程中激光照射区域组织转变为奥氏体,而在冷却过程中奥氏体发生马氏体转变;激光相变硬化处理后,完全淬火区主要以马氏体为主,其最大体积分数可达90%左右。相变区硬度提高约2倍,最大可达540.6 HV0.2;相变区的组织及硬度模拟结果与试验结果吻合较好。

Numerical simulation of microstructure on laser transformation hardening on inner wall of 42CrMo pump barrel

A 3-D finite element model was established for the numerical simulation of laser transformation hardening on the inner wall of pump barrel through a finite element code-SYSWELD.The change of thermal mechanical parameters with temperature was considered during the simulation.The metallurgy transformation was predicted by coupling phase evolution model with the results of temperature field.The hardness distribution was predicted using the simulation results of metallurgy transformation.The results show that laser transformation hardening is a fast heating and cooling process.During heating,the microstructure of laser heated zone is transformed to austenite which changes into martensite during cooling.After treatment,martensite could be achieved as a main phase in the hardened zone with a volume fraction of about 90%.The hardness of hardened zone is three times as that of base metal and the maximum value could reach 540.6 HV0.2.The predicted microstructure and hardness of the hardened zone agree well with the experimental results.