氯化聚乙烯反应釜内部锆复合层失效分析  

Failure Analysis of Internal Zirconium Composite Layer in CPE Reactor

作　　者：王金凯 商显栋 宋明大 张元[2] WANG Jin-kai;SHANG Xian-dong;SONG Ming-da;ZHANG Yuan(Shandong Special Equipment Inspection Institute,Jinan 250101,China;China University of Petroleum(East China),Shandong Qingdao 266580,China)

机构地区：[1]山东省特种设备检验研究院有限公司,济南250101 [2]中国石油大学(华东),山东青岛266580

出　　处：《失效分析与预防》2019年第5期336-340,共5页Failure Analysis and Prevention

摘　　要：通过金相检验、能谱分析、物相分析等技术手段对反应釜内部锆复合层焊缝处开裂问题进行分析,结果表明:该反应釜内部锆复合层的主要腐蚀形式包括点蚀、晶间腐蚀以及由于第二相引起的腐蚀;点蚀发生的主要原因是金属基体和氧化膜之间形成活化-钝化腐蚀电池,从而不断地从表面向内部腐蚀,形成点蚀;局部严重腐蚀的主要原因是在焊接过程中气体保护不充分,焊接时导热性不好或焊接参数过高,造成在焊缝处形成二氧化锆,导致晶界和晶粒之间存在电化学不均匀性,从而产生晶间腐蚀。The zirconium composite layer in CPE reactor cracked at the weld. The failure cause was analyzed by optical microscopy,EDS and XRD. The results show that the main corrosion forms of the internal zirconium composite layer include pitting,intergranular corrosion and corrosion due to the second phase. The main reason for the occurrence of pitting is the formation of an activation-passivation corrosion cell between the metal substrate and the oxide film, so that the corrosion continuously extended from the surface to the inside, forming punctiform pores. The main cause of local severe corrosion is insufficient gas protection during welding, poor thermal conductivity during welding or excessive welding parameters, resulting in the formation of zirconium dioxide at the weld and then resulting in the electrochemical inhomogeneity between grain boundaries and grains. The inhomogeneity produced intergranular corrosion.

关 键 词：R60702 焊缝 开裂 失效分析 

分 类 号：TQ052[化学工程]