加热器TP304不锈钢换热管腐蚀泄漏原因分析

Reasons Analysis on Leakage of TP304Stainless Steel Heat Exchanger Tubes of a Heater

通过宏观检验、化学成分分析、金相检验、力学性能测试、扫描电镜以及能谱分析等方法,对某加热器TP304不锈钢换热管腐蚀开裂泄漏原因进行了分析。结果表明:该TP304不锈钢换热管腐蚀泄漏区域有硫和氯元素沉积,显微组织中含有形变马氏体,其力学性能远远高于标准要求,导致换热管外表面产生应力腐蚀裂纹,裂纹不断扩展最终致使换热管泄漏;换热管固溶处理不充分和管程外的介质没有达到锅炉水质要求,是导致换热管产生泄漏的主要原因。

The leakage reasons of TP304stainless steel heat exchanger tubes of a heater were analyzed by means of macroscopic examination,chemical compositions analysis,metallographic examination,SEM and EDS analysis.The results show that there were sulfur and chlorine elements accumulation at the leakage position,and there was deformation-induced martensite in the microstructure,which led the mechanical properties of the tube to exceed standard requirement highly and stress corrosion cracking to happen at the tube outer surface,and the cracks expanded continuously and finally resulted in leakage.So the main reason for the leakage was that the solid solution treatment of the heat exchanger tubes was insufficient and the medium outside the tube did not meet the requirement of the water quality.