IN738高温合金焊后热处理残余应力数值模拟

Numerical simulation of residual stress of IN738 superalloy after post-weld heat treatment

采用三维有限元分析方法,对IN738高温合金激光焊接及热处理后的残余应力场进行数值模拟分析,研究了不同热处理方式对残余应力的影响。分析结果表明,IN738高温合金激光焊接完成后,热影响区残余应力最高,达到1040 MPa,超过了IN738合金室温时的屈服强度;焊件经900℃×15 h时效处理后,热影响区残余应力较焊接态降低了31%;经1120℃×2 h固溶和900℃×15 h时效处理后,热影响区残余应力较焊接态降低了49%,远低于IN738合金室温时的屈服强度。焊后采用固溶时效处理可以有效降低焊接残余应力。

The residual stress distribution of the IN738 superalloy laser welded and heat treated was analyzed by using 3 D finite element analysis method,and the effect of different heat treatments on the residual stress was studied. The results indicate that the residual stress in heat affected zone reaches the maximum value up to 1040 MPa,which exceeds the yield strength of the IN738 at room temperature. After aging at 900 ℃ for 15 h,the residual stress in the heat affected zone reduces by 31% compared with the welding state. And after heating at1120 ℃ for 2 h and aging at 900 ℃ for 15 h,the residual stress in the heat affected zone reduces by 49% compared with the welding state,which is significantly lower than the yield strength of the IN738 at room temperature. The post-weld solution and aging treatments can reduce the residual stress effectively.