CAJ | 학술논문

某厂生产的45Mn2螺栓进行拉伸实验时出现非正常断裂,采用宏观断口分析、金相分析等方法对断裂螺栓进行了分析.结果表明,非正常断口的形成是螺栓在拉伸前螺纹根部就存在裂纹.螺栓根部长的裂纹是淬火中形成的,在冷挤压螺栓时螺纹根部就形成微裂纹,这些微裂纹淬火时成为根部淬火裂纹形成的关键原因.
모엄생산적45Mn2라전진행랍신실험시출현비정상단렬,채용굉관단구분석、금상분석등방법대단렬라전진행료분석.결과표명,비정상단구적형성시라전재랍신전라문근부취존재렬문.라전근부장적렬문시쉬화중형성적,재랭제압라전시라문근부취형성미렬문,저사미렬문쉬화시성위근부쉬화렬문형성적관건원인.
The non-normal fracture appeared on 45Mn2 bolt during the tensile test was analyzed by macrofractography, metallographic analysis and so on. The results show that the non-normal fracture of the bolt is caused by generation of the crack in the root of thread before the tensile test; the long crack in the root of thread is formed by quenching, the micro-crack in the root of thread is formed in cold extrusion process and the micro-crack leads to the formation of the long crack by quenching.