20G/316L双金属复合管焊接接头数值模拟与分析

Numerical simulation and analysis of welded joint of 20G∕316L bimetallic composite pipe

针对机械复合方式的双金属复合管,运用了ANSYS软件中的APDL进行有限元数值模拟,重点对20G/316L复合管模型的焊接接头进行了热分析和应力场分析。结果表明,在双金属复合管焊接完成后,焊缝两侧焊接温度场并没有出现偏移现象。焊接产生的应力主要残留在20G和316L不锈钢的焊缝区域,应力状态在x,z方向即横、纵方向表现为拉应力,在y方向即垂直方向表现为压应力。通过对比各个焊接速度产生的焊接应力场分布,当焊接速度为110 mm/min时,应力曲线比较平滑稳定;当焊接速度>110 mm/min时,应力较低但会造成焊接不充分,残余应力分布不均匀;而当焊接速度<110 mm/min时,应力峰值过大,应力集中较明显,表明焊后残余应力较大。

For the bimetal composite pipe with mechanical coincidence mode,APDL in ANSYS software was used for finite element numerical simulation,focusing on the thermal analysis and stress field analysis of the welded joint of 20G∕316L composite pipe model.The results showed that there was no deviation in the temperature field on both sides of the weld after the welding of bimetal composite pipe.The stress generated by welding mainly remained in the weld area of 20G and 316L stainless steel.The stress state changed in x and z directions,namely the transverse and longitudinal directions,as tensile stress,and in y direction,namely the vertical direction,as compressive stress.By comparing the distribution of welding stress field generated by each welding speed,when the welding speed was 110 mm∕min,the stress curve was relatively smooth and stable.When the welding speed was greater than 110 mm∕min,the stress was low,but the welding was not sufficient,the distribution of residual stress was not uniform.However,when the welding speed was less than 110 mm∕min,the stress peak of the curve was too large and the stress concentration was obvious,indicating that the residual stress after welding was large.