风机机壳早期腐蚀开裂的影响因素  

Factors Affecting Premature Corrosion Cracking of Blower Casings

作　　者：孙少东[1] 盛定高[1] 舒韵[2] 王翔[2] 吴欣强[2] SUN Shaodong1, SHENG Dinggao, SHU Yun2, WANG Xiang2, WU Xinqiang2(1 Mechanical and Electrical Engineering Department, Huaian College of Information Technology, Huaian 223003, China 2 Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, Chin)

机构地区：[1]淮安信息技术学院机电工程系,淮安223003 [2]中国科学院金属研究所,沈阳110016

出　　处：《腐蚀科学与防护技术》2018年第2期202-206,共5页Corrosion Science and Protection Technology

基　　金：江苏省科技厅产学研合作促进计划项目(BY2014103)~~

摘　　要：研究了SAF2205双相不锈钢风机机壳腐蚀裂纹特征和腐蚀产物成分,表明机壳早期失效机制为Cl^-促进的应力腐蚀开裂(SCC),并且SCC裂纹萌生于机壳背面。分析认为,焊接导致焊缝附近区域组织发生变化,进而引起了机壳材料耐蚀性下降;泄漏的卤水蒸汽在机壳背面不断冷凝浓缩形成了强侵蚀性高浓度Cl^-水膜;焊接残余内应力叠加工作应力使得机壳所受应力值大幅度提高。风机机壳SCC失效是上述3个因素协同作用的结果,其中强侵蚀性高浓度氯离子水膜的存在是造成机壳早期SCC的关键因素。现场验证表明,去除覆盖在机壳背面的保温棉可有效预防其早期SCC开裂。The cracking feature and the corrosion product composition of a casing of SAF2205 duplex stainless steel were investigated for an out of operation blower. It is found that the premature failure of the blower casing is due to stress corrosion cracking（SCC） promoted by chloride ions, and the SCC initiates and propagates on the back surface of the casing. The welding caused the change of microstructure and degradation of corrosion resistance of the casing material. The water film rich in strong corrosive chloride ions was formed due to the continuouscondensation and concentration of the leaked brine steam on the back surface of the casing. The welding residual stress combined with the working stress made the casing stress increase to a great extent. The premature failure of the blower casing is induced by the synergic action of the above three factors, and the presence of the water film rich in strong corrosive chloride ions is the key factor. Removing heat preservation cotton covering on the back surface has been proved to be an effective measure to prevent the blower casing from SCC.

关 键 词：风机机壳 双相不锈钢 应力腐蚀开裂 卤水蒸汽 保温棉 

分 类 号：TG142.71[一般工业技术—材料科学与工程]