摘要
某压力容器用12. 9级螺栓在使用一段时间后发生断裂,通过化学分析、显微组织观察、断口观察等方法进行了分析,结果表明:螺栓分为两阶段断裂,螺牙根部存在多处集中分部的加工折叠缺陷,在随后的使用过程中在缺陷处产生应力集中,在裂纹在缺陷处萌生,随后由于氢脆产生沿晶扩展裂纹。在压力容器停用维修时已生成的裂纹被氧化为暗色,重新启用后,螺栓剩余未断裂部分可能经受异常较大受力,导致第二阶段为过载一次性断裂。
A class 12.9 bolt used for pressure vessel was broken after using for a certain period,and then the bolt was analyzed by means of chemical analysis,microstructure examination,and fracture observation. The results show that the fracture process is divided into two stages,lots of machining defects are found at the root of thread which induced stress concentration in service,thus the crack initiated at the defect area,then hydrogen embrittlement produced intergranular propagation crack. It is inferred that the fracture was oxidized to dark color during the maintenance of pressure vessel,then the remaining unbroken part of the bolt might undertake a bigger abnormal stresses and induced a second stage overload fracture when the vessel was put in use again.
作者
姚良
周君泽
陈亮
刘丽
Yao Liang;Zhou Junze;Chen Liang;Liu Li(Suzhou Metal Services Co.,Ltd.,Suzhou Jiangsu 215126,China)
出处
《金属热处理》
CAS
CSCD
北大核心
2019年第3期242-244,共3页
Heat Treatment of Metals
关键词
螺栓断裂
加工折叠缺陷
氢脆
过载断裂
bolt broken
machining folding defect
hydrogen embrittlement
overload fracture
