409L不锈钢后消连接管失效分析  

Failure analysis of the connecting pipe made of 409L stainless steel

作　　者：徐勇[1] 沈虹[1] 尹海[1] 

机构地区：[1]上海机动车检测中心,上海201805

出　　处：《金属热处理》2011年第3期111-113,共3页Heat Treatment of Metals

摘　　要：用409L不锈钢作焊管的汽车排气系统后消连接管使用一段时间后焊缝部位发生开裂。采用扫描电镜、金相、能谱检测、化学成分测试等方法对失效件进行综合分析。结果表明,409L钢连接管缝部位开裂的主要原因是燃烧尾气中的SO2与冷凝水反应生成的硫酸、亚硫酸等酸性液体使焊缝部位形成应力腐蚀裂纹,另外,焊缝部位的晶粒粗大促进其晶间腐蚀。The connecting pipe made of 409L stainless steel cracked in the weld joint during the service period.The fracture morphology,microstructure and chemical composition of the connecting pipe were analyzed by SEM,EDAX test and metalloscope.The results show that the cracking is mainly stress corrosion cracking（SCC） that occurs in weld joint caused by sulfuric acid and sulfurous acid solution,which is produced by the reaction of SO2 in the combustion exhaust and condensed water.In addition,coarse grain of the weld joint of the pipe promotes the intergranular corrosion.

关 键 词：409L不锈钢 连接管 焊缝开裂 应力腐蚀开裂 

分 类 号：TG172.3[金属学及工艺—金属表面处理]