常减压装置塔底奥氏体不锈钢弯头开裂原因分析及处理

Analysis for the Cracking of Austenitic Stainless Steel Elbows in Crude Distillation Unit and the Solution Measures

对某常减压装置塔底管线在检修开车期间,奥氏体不锈钢弯头出现开裂的问题进行了分析。从应力腐蚀环境,焊接残余应力,不锈钢的敏化三个方面探讨了常减压装置中连多硫酸应力腐蚀开裂引发的原因,并提出了相应的处理措施。

During the shutdown and restarting of a crude distillation unit,cracking was discovered on the elbows of stainless steel pipelines at the bottom of atmospheric and vacuum distillation columns.This paper figures out that the reason of the cracking is Polythionic acid stress corrosion cracking(PTA SCC).According to the stress corrosion environment,residual stress of welding and sensitization of austenitic stainless steel,the reasons of PTA SCC are analysed and mitigation methods are provided.