钢轨闪光焊焊缝断裂原因分析  

Cause analysis of flash weld fracture of rail

作　　者：邢丽贤[1] 邹定强[1] 杨其全[1] 

机构地区：[1]中国铁道科学研究院金属及化学研究所,北京100081

出　　处：《铁道建筑》2014年第9期109-112,共4页Railway Engineering

摘　　要：某运营线路一钢轨闪光焊焊缝发生全断面断裂,通过宏观、微观形貌观察,微区成分分析,金相组织、化学成分及低倍检验,分析钢轨闪光焊焊缝的断裂性质及断裂原因。分析结果表明:钢轨焊缝断裂性质为折叠裂纹导致的横向脆性断裂,在钢轨焊缝区域轨腰和轨底之间过渡圆弧部位的焊接推凸飞边根部形成的类似折叠裂纹缺陷导致疲劳裂纹的萌生,进而发展为横向脆性断裂。建议钢轨闪光焊焊接时尽量减小焊接推凸区厚度并避免在焊接推凸飞边根部形成类似折叠裂纹缺陷,防止焊缝发生横向脆性断裂。Full-section fractures appeared in the flash butt welding joint of one operation railway. This paper analyzed the fracture properties and causes by macro and micro observation, energy spectrum analysis,metallographic examination, chemical composition analysis and macroscopic examination. The test results showed that the fracture of the rail butt welding joint is transverse brittle fracture caused by fold crack, and that fatigue cracks appear because the similar fold crack defects formed from the welding pushing convex flash root in the arc transition area between the rail base and rail web of the rail welding zone, which results in transverse brittle fracture. It is suggested that welding pushing convex region thickness should be reduced and similar fold crack defects formed from welding pushing convex flash root should be avoided in rail flash butt welding, which could prevent transverse brittle fracture of the rail welding joint effectively.

关 键 词：钢轨闪光焊接 焊接推凸区 折叠裂纹 脆性断裂 

分 类 号：U213.46[交通运输工程—道路与铁道工程]