非停输管道焊接修复极限压力设计

Determination of extreme pressure for in-service welding of pipelines under repair

打孔盗油管线在焊接修复过程中产生的局部高温使热源周边材料强度降低,因此在非停输状态下进行焊接可能导致管道在内压作用下发生破裂事故。基于ANSYS有限元软件平台,对焊接修复过程中的温度场进行数值模拟,并根据模拟结果,计算管道的有效壁厚,从而确定在非停输状态下焊接修复时管道所能承受的极限压力,并进一步分析了焊接速度对极限压力的影响。结果表明,随着焊接速度的减小,管道承压能力降低。

During the course of repairing drilled pipelines, local high-temperature generated by welding leads to strength degrada- tion of the materials surrounding the heat source, and the in-service pipelines will blast if the internal pressure of the pipeline ex- ceeds some pressure limit. Based on ANSYS, dynamic finite element numerical simulation of welding for in-service pipeline was carried out and the effective wall thickness was calculated according to the distribution of temperature field. Based on the effective wall thickness, the extreme pressure that pipelines could bear was determined. Also, the effects of welding speed on extreme pres- sure were discussed. The results show that the extreme pressure of pipelines decreases with the decrease of the welding speed.