油气计量装置弯管接头腐蚀失效的原因

Corrosion Failure Reasons of Elbow Joint of an Oil and Gas Metering Device

采用宏观形貌、显微组织观察,腐蚀产物成分分析和电化学方法,分析了某采油厂计量装置采用的弯管接头在原油介质中发生穿孔的原因。结果表明:失效弯管接头热影响区存在焊接缺陷,导致其耐腐蚀性能减弱;腐蚀产物主要成分为FeOOH,氧腐蚀为主要腐蚀类型;弯管接头外弧侧耐腐蚀性能最弱,且不断受到流体冲蚀,腐蚀加剧,最终形成穿孔。

The reasons for perforation of the elbow joint used in metering device of an oil production plant in crude oil medium was analyzed by observation of macroscopic morphology,microstructure,composition analysis of corrosion products and electrochemical method.The results show that the heat affected zone of the failed elbow joint had welding defects,which weakened the corrosion resistance of the joint.The main component of corrosion products was FeOOH,and oxygen corrosion was the main corrosion type.The outer arc side of the elbow joint had the weakest corrosion resistance,and was eroded by the fluid continously,which led to more serious corrosion and perforation in the end.