移去热源前后中高碳钢堆焊温度场和应力场的数值模拟

Numerical simulation of temperature field and stress field of medium carbon steel before and after hardfacing

以中高碳钢60CrMnMo为研究对象,测量了堆焊后的残余应力场。采用有限元分析对热源移去前后堆焊温度场和应力场进行了数值模拟。残余应力场实测结果与模拟结果基本吻合,证明了模型的有效性。温度场模拟获得了不同时刻整个试样的温度分布及试样上各典型截面的温度变化曲线。堆焊16 s后移去热源前后温度场分布有很大差异,堆焊结束后,热量迅速向下表面及周界方向传播。直至180 s,试样温度场显现平衡态,传热基本停止,此时温度峰值位于靠近下表面心部,内外温差不大。利用温度场模拟结果模拟了堆焊热源移去前后几个关键时刻的瞬态过程应力。结果表明,应力峰值出现于热影响区与母材区交界面,跃变点前后变化十分显着。

The residual stress field of hot roller steel 60Cr-MnMo after hardfacing was measured by using X-ray stress analysis. From temperature simulation results, the temperature distribution of specimen and temperature curve at different location of the specimen at different time can be obtained, which can represent the whole process of temperature variation during hardfacing. When the hard-facing time is 16 sec, the temperature at different location of the specimen is very different. When hardfacing process is finished, the heat spread quickly to other directions. Up to 180 sec, the temperature is similar to each other between center and surface of the specimen, the temperature distribution of the whole specimen is uniform. The highest temperature appears near the lower surface. Comparison between the simulated results of the residual stress fields with measured ones shows that there is a good agreement with each other, which proves this model is effective. According to this model, the stresses at different time during cooling after hardfacing was simulated too by using the temperature field mentioned above. The results show that the tensile stress at the dangerous location appears at the interface, change of stress between the mutation is great.