背面冷却对316L对接接头焊接残余应力和变形的影响

Effect of Back Cooling on Welding Residual Stress and Deformation of Butt Joint of 316L Steel

基于热弹-塑性理论和有限元理论,以Abaqus软件为平台,结合Python和Fortran语言编辑程序建立分析步、控制焊缝单元生死和施加双椭球热源载荷,考虑材料热物理性能、力学性能的非线性,开发了焊接热、力耦合有限元模型,分析了作用于焊缝背面的冷源宽度、冷源功率对316L不锈钢对接接头焊接残余应力和变形的影响规律。结果表明:随着冷源宽度、冷源功率的增加,焊缝表面的纵向、横向残余拉应力峰值降低;当冷源宽度大于20 mm时,上侧焊缝表面的纵向残余应力峰值降低不明显,即冷源宽度存在最佳值;随着冷源功率的增加,上侧焊缝表面的残余应力峰值降低幅度减少,下侧焊缝表面的残余应力峰值降低幅度明显。此外,随着冷源宽度、冷源功率的增加,焊件的变形增加;当冷源宽度大于20 mm时,增加冷源宽度对变形的影响不明显。

Based on theory of thermoelasto-plasticity and finite element,taking Abaqus software as the platform,a thermal-mechanical coupling finite element model for the welding of butt joint was established by using Python language editing program to establish analysis steps and to control the death and birth of the weld elements,and using Fortran language editing program to apply double ellipsoid heat source load.The nonlinearity of thermal physical properties and mechanical properties of material was considered in modeling process.The effects of width and power of the back cold source on the welding residual stress and deformation of 316L stainless steel butt joint were analyzed.The results show that with the increase of the width and power of the cold source,the peak value of longitudinal and transverse residual tensile stress on the weld surface decreases.However,there is an optimal value for the width of cold source.When the width of cold source is greater than 20 mm,the peak value of longitudinal residual stress on the upper weld surface does not decrease significantly.With the increase of cold source power,the peak value of residual stress on the upper weld surface does not decrease significantly,while the residual stress on the lower weld surface decreases obviously.In addition,with the increase of the width and power of the cold source,the deformation of the weldment increases.When the width of the cold source is greater than 20 mm,the effect of increasing the width of the cold source on the deformation value is not obvious.