不锈钢气管泄漏分析

Analysis on leakage of stainless steel vent-pipe

通过宏观检验、化学成分分析、金相检验、扫描电镜以及能谱分析等方法,对TP316不锈钢气管腐蚀开裂泄漏原因进行分析。结果表明,该气管的化学元素组成符合相应的材料标准,通过能谱分析显示腐蚀泄漏区域具有硫和氯元素沉积,显微组织中含有形变马氏体,固溶处理不充分,另外该气管在冷拔后没有进行去应力退火,在管内通入的气体中含有硫、氯等杂质元素情况下,导致气管的内表面产生应力腐蚀裂纹,裂纹不断扩展,最终致使气管泄漏。因此,应力腐蚀是导致气管产生泄漏的主要原因。

The corrosion cracking and leakage reasons for TP316 stainless steel vent-pipe were analyzed by means of macroscopic examination, chemical compositions analysis, metallographic examination, SEM and EDS analysis. The results show that the chemical elements of vent- pipe are complying with the relevant material standards, and the EDS results show that there are sulfur and chlorine elements deposition at the corrosion leakage position, and there is deformation martensite in the microstructure, which indicates that the solution treatment is insufficient. In addition, the vent-pipe without stress annealing after cold drawing is inlet gas containing sulfur, chlorine and other impurity elements, which lead to stress corrosion cracking at the inner surface of vent-pipe, and the cracks expanded continuously and finally cause leakage. The main reason for the vent-pipe leakage was stress corrosion.