交流发电机前端盖断裂分析

Fracture analysis of front end cover of alternator

某国产品牌轿车在装配后试车阶段交流发电机前端盖发生断裂,通过断口宏微观观察、金相组织检验、扫描分析及EBSD分析等方法对断裂零件进行分析。结果表明,由于零件材料本身存在较多冷豆缺陷,严重地降低了材料的力学性能,在外力作用下,由应力集中处开裂。试样组织中存在较多脆性相Fe相及氧化夹渣,同样也降低了材料塑性,对断裂也起到了促进作用。

The front end cover of an AC generator of a domestic brand car broke during the test run after assembly. The fracture parts were analyzed by means of macro and micro observation of fracture surface, metallographic examination, scanning analysis and EBSD analysis. The results show that there are many cold bean defects in the material itself, which seriously reduces the mechanical properties of the material. Under the action of external force, the material cracks at the stress concentration. There are more brittle Fe phases and oxidized slag in the sample structure, which also reduces the plasticity of the material and promotes the fracture.