摘要
通过金相和扫描电镜观察、显微硬度检验、化学成分分析对某门式起重机主梁连接螺栓的断裂原因进行了分析。结果表明:裂纹源头位于螺纹根部加工缺口处;由于螺栓内部组织是板块状回火马氏体和针状下贝氏体,脆性较大,当螺栓承受较大外应力时,裂纹沿着内部微裂纹和孔洞扩展,最终发生断裂。
Through the metallographic and scanning electron microscope observation, micro-hardness test, chemical composition analysis, fracture reasons of a door type crane main beam connecting bolts were analyzed. The results show that the crack source locates at the machined breach of the root of the thread; as the internal microstructure of the bolt is the plate-shaped tempered martensite and acicular lower bainite, its brittleness is greater, and when the bolt bears larger external stress, cracks expand along microcracks and the holes, and eventually rupture occurs.
出处
《热加工工艺》
CSCD
北大核心
2017年第7期249-250,257,共3页
Hot Working Technology
基金
广东省质监局科技项目(2015CT02)
广州市创新平台建设与共享专项项目(201509010008)
