摘要
螺钉在装配时发生断裂。采用扫描电镜和金相检查对螺钉断口进行宏观和微观分析,并进行硬度及化学成分检测。螺钉断口均呈沿晶形貌,局部有韧窝,晶界面上有细小条状的撕裂棱线;金相组织为回火索氏体;化学成分符合标准要求;显微硬度值明显高于正常螺钉硬度值。结果表明,螺钉热处理不当,造成抗拉强度明显过高;同时酸洗过程中,螺钉在酸溶液中浸泡时间过长,致使大量氢渗入螺钉,增大了螺钉氢脆的敏感性,最终导致螺钉氢致脆性断裂。
The screws appear fracture during the assemblage. The screw fracture were macro and micro analyzed by means of scanning electron microscope and metallographic examination, hardness testing and chemical components inspection. The screw fracture occur intergranular profile, local has dimple, the grain boundary surface has a small strip tearing ridge. Microstructure is tempered sorbite. Chemical composition meets the requirements of standard. Microbardness value is significantly higher than normal screw hardness. The results show that the higher strength is caused by improper heat treatment, and immersion time of screw in acidic solution is longer in the process of acid pickling, which increase the sensitivity of hydrogen embrittlement, and the fracture of screw was finally caused by the hydrogen embrittlement.
出处
《金属制品》
2016年第2期64-66,共3页
Metal Products
关键词
螺钉
氢脆断裂
抗拉强度
酸溶液
screw
hydrogen embrittlement fracture
tensile strength
acidic solution
