连续油管环焊温度场及残余应力场数值分析

Numerical Analysis on Circumferential Welding Temperature Field and Residual Stress Field for Coiled Tubing

采用有限单元法,初步模拟了连续油管环焊温度场及残余应力场的分布情况。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;随着焊接热源的移动,温度中心也随之移动,最高温度可达母材的熔点;在每一道焊接结束后,温度迅速下降,越接近层间温度,降温所用的时间也越长。焊后残余应力主要分布在焊缝附近,管体其他部位应力很小,只有几十兆帕;最大残余应力在焊缝壁厚的中心位置,其值为592 MPa,应力值较大,建议采用相关热处理技术来消除焊缝处的残余应力。

The circumferential welding temperature field and residual stress distribution of the coiled tubing were simulated initially with the method of finite element method.The results showed that temperature gradient was great near the weld and remained even away from the weld.With the movement of welding thermal source,the temperature center also moved and the maximum temperature was up to the melting point of the base metal;the temperature dropped rapidly after each welding,the closer to the interlayer temperature and the longer cooling time need.Post welding residual stress distributed near to weld only a few dozen Megapascal in other parts of pipe body,the maximum residual stress 592MPa presented in the center of weld wall thickness.It suggests the residual stress in weld should be eliminated by related heat treatment technology.