套管结构异种金属多层多道焊接数值模拟

Numerical simulation of multi-layer multi-pass welding for dissimilar metals in casing pipe structure

采用SYSWELD焊接专用模拟软件模拟分析套管结构异种金属多层多道焊接温度场和应力场,并采用金相截面和X射线衍射应力测试校核模型。结果表明,采用校核后的热源模型模拟的焊接温度场推断形成的焊缝截面与实际一致,焊缝根部节点温度随时间变化曲线存在14个温度起伏,每个起伏有2个温度峰值;采用X射线衍射实测残余应力与模拟结果基本吻合,不同焊接位置的轴向残余应力分布规律相同,焊接位置为0°和90°时轴向残余应力较大,最大残余应力数值接近300 MPa;不同焊接位置环向残余应力数值大小分布相同,距离首道焊缝根部15 mm处的最大环向残余压应力接近300 MPa;最大Von Mises应力出现在低合金钢热影响区,90°焊接位置最大Von Mises应力值为377 MPa。

Special welding simulation soft SYSWELD is applied to simulate temperature field and stress field of multi-layer muhi- pass welding for dissimilar metals in casing pipe structure,and the metallographic section observation and X-ray diffraction stress test are used to check the simulation model. The results show that the weld section obtained by simulative welding temperature field of checked model is consistent with the actual weld section,the temperature of the root joint fluctuates 14 times over time.each fluctuation has two peaks; simulation results are basically same with residual stress measured by X-ray diffraction, the distributions of axial residual stress at different welding position demonstrate similar regulation,axial residual stress at welding position of 0 degree and 90 degree are much higher,and the maximum residual stress is close to 300 MPa;numerical valves and distribution of circumferential residual stress at different welding position are same,the maximum circumferential residual stress is close to 300 MPa at 15 mm away from the root of first weld;the maximum Von Mises stress appears in the heat affected zone of low alloy steel,and the maximum Von Mises stress at welding position of 90 degree is 377 MPa.