X80钢连头管段长度对焊缝附近残余应力的影响

Influence of length of X80 steel pipe tie-in on residual stress near the weld

随着经济快速发展,薄壁大管径的高钢级管道应用广泛。由于管道铺设受到多种外加因素的影响,在实际施工过程中不可避免地需要采用连头连接两侧管道。连头的长度是可变化的,因此针对连头口管段长度变化展开连头口焊缝有限元分析及ECA评估。研究了连头管段长度对连头口焊缝附近残余应力变化的影响。根据有限元结果可知,随管段长度的增加,连头口焊缝附近的残余应力水平显著下降。且管段长度在大于3000 mm时,残余应力下降速率减缓。之后考虑残余应力的影响,开展了不同长度连头管段的ECA评估研究,评估结果表明,随着连头管段长度的增加,可接受的临界裂纹尺寸增大。因此在一定的范围内,为尽可能减少焊缝附近的残余应力集中,应适当增加连头口两侧连头管段长度。

The rapid development of the economy brings the wide application of high steel pipelines with thin walls and large diameters.Tie-in is indispensably used to connect two sides of the pipeline due to many external factors on pipeline laying in the actual construction process.The length of the tie-in is variable,so finite element analysis and ECA evaluation of the weld are carried out towards the change of the tie-in pipeline length.The influence of different lengths of tie-in pipelines on the residual stress near the weld is studied.According to the finite element results,the residual stress near the weld decreases significantly with the increase in pipeline length.When the pipeline length is greater than 3000 mm,the decline of residual stress slows down.Then,ECA evaluation studies were carried out for different length of tie-in considering the influence of residual stress.The evaluation results show that the acceptable critical crack size increases with the increase of the length of the tie-in.Therefore,in the acceptable range,to reduce the residual stress concentration near the weld as much as possible,the pipeline length on both sides of the joint should be appropriately increased.