手拉葫芦用吊钩断裂原因分析

Fracture of Hand Chain Block Hook

采用金相组织、宏观形貌、SEM等方法,对吊钩早期断裂失效的原因进行分析。结果表明:该吊钩的断裂性质属于过载脆性断裂,其主要原因是吊钩终锻温度过高,导致粗大魏氏组织和晶粒形成,从而降低了材料的强度和增大了材料的脆性;当吊钩荷载大于材料强度时,裂纹在最薄弱的吊钩内缘产生,随后快速扩展至脆性断裂。据此提出吊钩改善热处理工艺制度和加强生产质量检验的建议。

The reasons for the early fracture of the hook on the hand chain blocks are investigated in the paper by means of metallographic structure, macro morphology and SEM. The results show that the property of the hook failure is the overload brittle fracture, and the main reason is found that the forging-ending temperature of the hook is too high, resulting in the coarse Widmanstatten structure and coarse grain, which not only reduce the strength of the material, but also increase the brittleness of the material. And when the load on the hook exceeds the strength of the material,crack initiation is on the inner edge of the hook, and expends rapidly to the brittle fracture. Based on the findings, the suggestions are made that include the improvement of the heat treatment process system as well as that of the quality inspection of the hook in production.