球罐裂纹成因分析

某公司一台液态烃球罐,按计划进行大修检查时在内表面发现较多微裂纹,裂纹最深达5.9mm。在现场检查、测厚、金相分析、腐蚀产物分析并结合工艺情况分析的基础上,初步判断裂纹是应力导向氢致开裂裂纹,裂纹产生的主要原因是罐内物料介质中硫化氢含量严重超标。建议在罐内采用涂层或阴极保护层的方法来阻止或减缓湿硫化氢环境中的腐蚀,从而降低裂纹的产生与发展的可能性。

Study on Cracks Formation of Spherical Tanks

In the scheduled overhaul investigation of a liquid hydrocarbon spherical tank in a company,many micro cracks were found in the internal wall,whose maximum depth was 5.9 mm.The site investigation,thickness measurement,metallographic analysis,corrosion product analysis and process condition analysis preliminarily concluded that the cracks were stress oriented hydrogen induced cracking(SOHIC),which was mainly caused by serious off-specifications of H2S in storage media in spherical tank.It was suggested to apply coating or cathodic protection to prevent or mitigate the corrosion in wet H2S environment.