摘要
某单位生产的汽车门窗用10.9级20钢高强度螺钉在服役约一个月后相继出现多个断裂现象。利用光学显微镜、扫描电子显微镜、直读光谱仪、能谱分析仪和显微硬度计等对螺钉的断裂原因进行了分析。结果表明:该螺钉断裂的主要原因是其在使用之前就存在微裂纹,造成应力集中,在静载荷拉应力的作用下,材料中的氢原子向裂纹尖端移动、富集,使局部氢浓度较高,导致螺钉发生了氢致延迟脆性断裂;另螺钉表面硬度过高也增加了其对氢脆断裂的敏感性。
10.9 grade high strength screws made of 20 steel fractured after being used for about one month. Macro-examination,chemical compositions,hydrogen content,micro-hardness,microstructure,EDS and SEM analysis were carried out on the cracked screws.The results show that the screws existed micro cracks before using. The primary cracks made stress concentration,so the hydrogen in material moved to the crack top,enriched and caused of tension stress.The hydrogen content continuous to increase,while it come to the up-limited of the fracture hydrogen content,the screws occurred hydrogen ductile-brittle fracture.
出处
《理化检验（物理分册）》
CAS
2010年第4期263-266,273,共5页
Physical Testing and Chemical Analysis(Part A:Physical Testing)
关键词
高强度螺钉
微裂纹
应力集中
氢致延迟脆性断裂
high strength screw
micro-crack
stress concentration
hydrogen ductile-brittle fracture
