碳钢与304不锈钢焊接残余应力的计算

采用弹塑性有限元法计算了Q235碳钢与304不锈钢的焊接温度场和焊接残余应力,计算结果表明,由于二者物理性能的差异造成了焊接温度场和残余应力分布的不均匀,焊接残余应力的峰值出现在304不锈钢一侧,其值略低于304不锈钢的屈服强度.当焊接热源偏向Q235钢时,焊接残余应力峰值变化较小,但高应力区减小,焊接变形明显减小,当焊接热源偏向304不锈钢时结果相反.当焊接热输入增大时会导致焊后高应力区范围的扩大,残余应力的峰值略有降低.采用红外热像仪测量了焊接过程中焊接接头上表面的温度变化情况,有限元计算的结果与其符合较好.

Welding residual stress calculation of carbon steel and stainless steel joint

Elasto-plastic finite element method is used for simulating the welding temperature field and the residual stress in butt-welded Q235 and 304 stainless steel.The results indicate that differences between their physics property caused the inhomogeneous distribution of the welding temperature field and the residual stress.And the peaks of the residual stress show on 304 stainless steel side,and the peak value is slightly less than the yield strength of 304 stainless steel.When the heat source was moved towards Q235,the peak value had small changes,but the high-stress and the welding distortion were decreased.On the contrary,when the heat source was moved towards 304 stainless steel,the high-stress area would be expanded with higher welding heat,and the peak value of the residual stress was slightly decreased.An infrared thermal imager was also applied to measure surface temperature changing of welding materials in welding process,the results are in accordant with that drawn from elasto-plastic finite element simulation.