某热力管线上不锈钢膨胀节开裂原因分析

Analysis of the Causes Leading to Cracking of RJ16-1000BI Stainless Steel Expansion Joint of a Hot-Water Transporting Pipe

某热力管线上RJ16-1000BI型不锈钢膨胀节运行4a后发生爆裂。调查了设备现场使用状况,取样分析了腐蚀产物的化学成分,用扫描电镜观察了断口形貌,同时根据现场条件进行了模拟腐蚀试验。试验结果表明,RJ16-1000BI型不锈钢膨胀节失效是因为严重的氯化物应力腐蚀和局部腐蚀导致的。

The RJ16-1000BI expansion joint made of stainless steel in heating system experienced cracking after being put into use for four years.Thus the state of the expansion joint in field application was investigated.The chemical composition of the parent metal and corrosion products was analyzed.The fractured surface of the failed parts were examined using a scanning electron microscope,aiming at revealing the causes leading to the cracking of the expansion joint.It was found that the failure of the expansion joint was attributed to severe chloride stress corrosion cracking and partial corrosion.