打孔管道焊接修复结构的残余应力测试

输油管道上的打孔盗油案件时有发生。对被打孔的管道，只能采用焊接方法抢修，而焊接产生的残余应力影响管道承压能力和剩余寿命。为了解管道修复中焊接残余应力对管道完整性的影响，用钻孔法分别测试了打孔管道的不同焊接修复结构的残余应力，并和管道螺旋焊缝处的残余应力进行了对比。测试结果表明，焊缝近处存在残余应力，且距焊缝越近，残余应力越大。管道修复结构中的残余应力的第一主应力多为拉应力，其最大值为管材屈服极限的70．94％；管道螺旋焊缝处的残余应力的第二主应力为压应力，其最大值约为管材屈服极限的74.66％。同时在焊接接管的根部存在较大的残余应力。

Residual stress test on welding repair structure of drilled pipeline

Some oil transmission pipelines are often drilled holes by oil stealers, These drilled pipelines must be repaired by welding way in time. The residual stress produced in welding process has effects on the loading capability and service life of pipelines, The residual stress tests were conducted on different weld structures of repaired pipelines by drill-hole method in order to investigate the influence of welding repair on pipeline integrity. The test results show that there exists the residual stress near a weld seam, and the closer distance from a weld seam is, the higher residual stress is. The first principal stresses of residual stresses on welding repair of the drilled pipeline are mostly tensile. The highest residual stress in tensile is about 70.94% of the yield limit of pipe material. Whereas the second principal stresses of residual stresses near a spiral weld seam are compressive. The highest residual stress in compression is about 74.66% of the yield limit of pipe material. In addition, the high residual stress occurs at the bottom of a tube welded on pipelines.