镍铬基合金管结构GTAW打底焊接变形和残余应力的有限元预测

Finite Element Prediction of Residual Stress and Deformation for Nickel-chromium Based Alloy Tube Structure GTAW Bottom Welding

采用钨极惰性气体保护焊(GTAW)方法对大口径Inconel 718镍铬合金管结构进行打底焊接,采用数值模拟方法预测了焊缝及其邻近区域的温度场、残余变形和残余应力的分布。数值模拟时,考虑了材料热物理性能参数随温度变化的非线性关系,同时也考虑了相变潜热对温度变化的影响。结果表明,最大焊接残余变形为0.236681 mm,主要分布于焊缝及其邻近区域;残余应力主要以轴向残余拉应力为主,在0°和90°位置,最大值分别为468.5和307.9 MPa;在180°和270°位置,最大值分别为152.9和58.2 MPa。

Inconel 718 nickel-chromium alloy tube structure with large diameter was GTAW backing welded, the distribution of temperature field, residual deformation and residual stress of the weld and its surrounding area was predicted by numerical simulation. In numerical simulation, the nonlinear relationship of thermo-physical performance parameters varying with temperature was considered, and the latent heat of temperature change was also considered. The results show that the largest welding residual deformation is 0.236681 mm, which mainly distribute at the weld and its surrounding areas, and the residual stress is mainly axial residual tensile stress . At the 0° and 90° position, the maximum is 468.5 and 307.9 MPa, respectively. At 180° and 270° position, the maximum value is 152.9 and 58.2 MPa, respectively.