某气田316L双金属复合管焊缝腐蚀穿孔原因分析

Cause Analysis of Corrosion and Perforation of 316L Bimetallic Composite Pipe Weld in a Gas Field

本文采用金相、扫描电镜等方法分析了新疆某气田地面集气系统316L双金属复合管的焊缝的腐蚀原因。结果表明:该双金属复合管焊缝处腐蚀穿孔是沉积在管线底部腐蚀性较强的地层水使其产生的点蚀破坏,并且复合管碳钢外管与不锈钢内衬管、不锈钢焊缝之间发生电偶腐蚀,加速复合管碳钢外管的腐蚀破坏,使焊缝处腐蚀孔洞进一步地发展。

In this paper,the corrosion causes of welds of316L bimetallic composite pipe in a gas field in Xinjiang are analyzed by metallography and scanning electron microscopy.The results show that the corrosion perforation at the weld of the bimetallic composite pipe is the pitting corrosion caused by the formation water of strong corrosive at the bottom of the pipeline,and galvanic corrosion occurs between the carbon steel outer tube of the composite pipe and the stainless steel inner liner and the stainless steel weld,accelerate the corrosion of the carbon steel outer tube of the composite pipe,so that the weld at the further development of corrosion holes.