不锈钢焊接波纹管失效原因分析

Failure Analysis of Expansion Joint of Stainless Steel Bellows

针对某公司不锈钢波纹管膨胀节开裂失效进行了化学成分分析、硬度测试,并进行了裂纹部位金相组织分析、断口解理和断口异物的能谱分析。研究表明,不锈钢波纹管材质的化学成分符合相关技术要求,但主要合金元素铬、镍含量均处下限;断裂面腐蚀区含有与硫、氯相关的腐蚀物,波纹管内壁峰底区加工后的拉应力和服股中拉应力迭加作用下产生应力腐蚀开裂。

The expansion joint cracking failure is analyzed by chemical composition analysis,hardness testing,metallographic analysis,crack fracture and fracture energy spectrum analysis.All these show that the chemical composition of stainless steel bellows material is in accordance with the relevant technical requirements,but the main alloying elements content of Cr and Ni are lower;the fracture surface corrosion zone contains S and Cl corrosion related,and the occurrence of stress corrosion by the tensile stress after the processing of the peak bottom area with the tensile stress in use together has been proved.