法兰开裂原因分析  

Failure Analysis of Flange Crack

作　　者：王影[1] 谢国君[1] 韩露[1] 逄锦程[1] WANG Ying XIE Guo-jun HAN Lu PANG Jin-cheng(Aerospace Research Institute of Materials ＆ Processing Technology, Be~l＇ing 100076, China)

机构地区：[1]航天材料及工艺研究所,北京100076

出　　处：《失效分析与预防》2016年第6期369-371,共3页Failure Analysis and Prevention

摘　　要：不锈钢法兰安装到发动机上后在宁波停放5年,检查发现多件法兰表面均存在多条径向裂纹。通过对裂纹及断口形貌观察、金相分析、材料成分检测,分析法兰的断裂原因。结果表明,法兰的开裂模式为应力腐蚀,发生应力腐蚀的原因是由于法兰所用材料牌号与设计要求不符合,用1Cr17Ni7材料代替了304不锈钢,而1Cr17Ni7材料的耐腐蚀及晶间腐蚀性能均比304不锈钢差,同时1Cr17Ni7材料组织存在沿晶分布的网状碳化物,导致其耐晶界腐蚀能力进一步下降。There were many radial cracks on the stainless steel flange surface after storing for five years in Nibo. Marco and micro observation,chemical composition analysis and metallurgical examination were carried out to find out the failure cause. The results show that the fracture mode is stress corrosion. The material of the flange is 1Cr17Ni7,but the not required material：304. The corrosion resistance of 1Cr17Ni7 is poorer than that of 304. In addition,the carbide network along the grain boundaries in the 1Cr17Ni7 promoted the occurrence of stress corrosion.

关 键 词：法兰 不锈钢 应力腐蚀 网状碳化物 

分 类 号：TG115[金属学及工艺—物理冶金]