某地铁用锚固螺栓断裂原因分析
张金,邹定强
(中国铁道科学研究院 金属及化学研究所,北京 100086)
摘要:某地铁用锚固螺栓在使用过程中发生断裂失效。采用断口形貌检查、扫描电镜观察、化学成分分析、硬度测试及金相显微组织分析等方法,分析了螺栓的断裂性质和失效原因。结果表明,螺栓的断裂性质属于疲劳断裂。螺栓滚丝成型时,在螺纹齿根处形成了拉伤沟表面缺陷,使该处的抗疲劳性能降低,且使用过程中螺纹齿根处易产生应力集中,从而促进了疲劳裂纹的萌生及扩展,最终导致螺栓断裂失效。
关键词:地铁;锚固螺栓;表面缺陷;疲劳断裂
中图分类号:U213.5+2           文献标识码:B        文章编号:1006-0316 (2013) 05-0071-03
Reason analysis on fracture of anchor bolt with a subway
ZHANG Jin,ZOU Ding-qiang
( Metals & Chemistry Research Institute, China Academy of Railway Sciences, Beijing 100086, China )
Abstract:Anchor bolt of a subway during using process occurred fracture failure. By fracture appearance examination, scanning electron microscope (SEM) observation, chemical composition analysis, hardness testing, metallurgical microstructure analysis and other methods, the fracture mode and failure reasons of the bolt were analyzed. The results show that the fracture mode of the bolt is fatigue fracture. With bolt thread rolling forming, the thread root place form strain groove surface defect, to reduce its anti-fatigue performance, and the thread root place during using process easy to produce stress concentration, so as to promote the fatigue crack initiation and propagation, which eventually led to the bolt fracture failure.
Key words:subway;anchor bolt;surface defect;fatigue fracture

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收稿日期:2012-11-08
作者简介:张金(1981-),男,黑龙江哈尔滨人,硕士研究生,助理研究员,主要从事金属材料研究及失效分析工作。
 

 

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