直缝埋弧焊管焊接残余应力的数值模拟

Numerical Simulation of SAWL Pipe Welding Residual Stress

直缝焊管焊接过程中产生的焊接应力和变形会影响焊管的使用性能和寿命。应用大型通用软件ABAQUS,基于双椭球热源模型,利用"生死单元"技术,模拟了直缝焊管多丝埋弧焊的内外焊接过程,描述了准稳态温度场和残余应力场计算数值及其在整个管体上的分布情况。结果表明,在焊接过程中焊缝附近温度梯度很大,在远离焊缝的地方温度梯度渐渐趋于平缓;随着热源的移动,温度中心也随之移动,最高温度可达母材的熔点。焊后残余应力主要分布在焊缝附近,管体在其他部位应力很小,最大残余应力为528 MPa;纵向残余应力在焊缝及热影响区表现为拉应力,并且最大值位于焊缝长度中心截面上;在圆周上表现出拉应力并伴有逐渐变小的趋势。

The welding stress and deformation produced during SAWL pipe welding process affect the performance and working life of pipe. By using general finite element method （FEM） software ABAQUS, based on double-ellipsoid heat source model, to simulate the inside and outside welding process of SAWL pipe through the “ birth-death element” technology, and described the distribution of quasi-steady temperature field and residual stress field on the whole pipe body. The results indicated that during welding process, the temperature gradient near weld is large;it is tend to smooth transition far away from the weld. With welding heat source moving, the temperature center also move, the highest temperature can reach the melting point of base metal. The residual stress after welding mainly distributed near weld, the residual stress in other parts of pipe is small, and the largest value of residual stress is 528 MPa. The longitudinal residual stress in weld and HAZ show tensile stress. On the circumferential direction, the longitudinal residual stress show tensile stress and accompanied by the trend of gradually smaller.