加氢装置原料运输线排污管节腐蚀失效原因  

Reasons for Corrosion Failure of Sewage Pipe Section in Hydroprocessing Uni

作　　者：柳旺 尤景泽 刘凯 郭静[1] 王汉奎[1] LIU Wang;YOU Jingze;LIU Kai;GUO Jing;WANG Hankui(China Special Equipment Inspection&Research Institute,Beijing 100029,China)

机构地区：[1]中国特种设备检测研究院,北京100029

出　　处：《腐蚀与防护》2024年第8期109-113,共5页Corrosion & Protection

基　　金：国家市场监督管理总局科技计划项目(2019MK134)。

摘　　要：某加氢装置原料运输线排污管节发生了腐蚀开裂。通过宏微观形貌观察、化学成分分析、腐蚀产物成分分析、金相检查等手段分析了管节腐蚀失效的原因,并提出了相应的改进措施。结果表明:管节化学成分和组织正常,管节材料未敏化;裂纹从管节内壁开始扩展至外壁,分叉特征明显,为穿晶裂纹;断口表面腐蚀产物中残存着氯元素。综合裂纹特征和腐蚀产物成分可以推断该管节发生了由氯离子引起的应力腐蚀开裂。管节两端存在较大的温差,造成了局部水相析出,介质中的腐蚀性氯元素在水相中聚集,形成应力腐蚀开裂的环境。Corrosion cracking occurred in a sewage pipe section of a raw material transport pipeline of a hydrogenation unit.The reasons of corrosion failure of the pipe section were analyzed by means of macro and micro morphology observation,chemical composition analysis,corrosion product composition analysis and metallographic examination,and the corresponding improvement measures were put forward.The results show that the chemical composition and microstructure of the pipe section were normal,and the material of the pipe section was not sensitized.The cracks extended from the inner wall to the outer wall of the pipe section,showing the obvious feature of bifurcation,and were transgranular cracks.Chlorine element remained in the corrosion products on the fracture surface.Stress corrosion cracking caused by chloride ion could be inferred from the crack characteristics and the composition of corrosion products.There was a large temperature difference at both ends of the pipe section,resulting in water phase precipitation in partial zone.And corrosive chlorine in the medium accumulated in the water phase,forming a stress corrosion cracking environment.

关 键 词：加氢装置 管节 应力腐蚀 347不锈钢 

分 类 号：TG172[金属学及工艺—金属表面处理]