Φ88.9 mm×6.45 mm L80-13Cr油管穿孔原因分析

Cause Analysis of Φ88.9 mm×6.45 mm L80-13Cr Tubing Perforation

针对Φ88.9 mm×6.45 mm L80-13Cr油管穿孔现象,采用宏观分析、化学成分分析、金相分析、力学性能测试及扫描电子显微镜、能谱仪等手段,对规格为Φ88.9 mm×6.45 mm的L80-13Cr马氏体不锈钢油管发生穿孔的原因进行了分析。结果表明:该油管材质的化学成分、显微组织及力学性能等未见异常,但内壁存在严重的均匀腐蚀以及孔蚀,腐蚀形貌呈苔地状,腐蚀产物及腐蚀坑内填充物主要为Fe_(3)O_(4)、FeOOH、FeCr_(2)O_(4)及CrOOH。因此穿孔的发生主要是由于油管内壁的水中存在溶解氧,导致油管发生了严重的均匀腐蚀及孔蚀,孔蚀处壁厚减少,导致油管穿孔。

In order to solve the perforation ofΦ88.9 mm×6.45 mm L80-13Cr tubing,the reasons for perforation of L80-13Cr martensitic stainless steel tubing with the specification ofΦ88.9 mm×6.45 mm were analyzed by means of macro analysis,chemical composition analysis,metallographic analysis,mechanical property test,scanning electron microscope and energy spectrometer.The results show that the chemical composition,microstructure and mechanical properties of the tubing are normal,but there are serious general corrosion and pitting corrosion on the inner wall.The corrosion morphology is lichen like and the main corrosion products and fillers in corrosion pits are Fe_(3)O_(4),FeOOH,FeCr_(2)O_(4) and CrOOH.Therefore,the occurrence of perforation is mainly due to the dissolved oxygen in the water of the inner wall of the tubing,which leads to serious general corrosion and pitting corrosion of the tubing.The wall thickness of the pitting corrosion is reduced,which leads to the perforation of the tubing.