地铁钢轨闪光焊缝裂纹伤损成因分析与对策——以杭州地铁某线为例

Analysis and Countermeasures on Flash Weld Crack Damage of Subway Rails——Taking a Hangzhou Subway Line as an Example

以杭州地铁某线发生的闪光焊缝裂纹伤损作为研究对象,分析裂纹伤损成因,通过统计裂纹伤损在不同列车线型、运行方向、运行频次及钢轨部位下的发生频率,明确裂纹伤损的易发场景,开展对策研究。分析发现:1)在圆曲线区段最易出现闪光焊缝裂纹伤损,从焊缝裂纹伤损数的每公里占比角度,以及导致需加固或更换大修的线型占比角度分析可知,圆曲线区段出现的频率均高于缓和曲线区段和直线区段;2)线路上行区段相比下行区段更易出现裂纹伤损;3)在单位时间内,列车作用频次越多,越容易导致裂纹伤损的出现。为降低闪光焊缝裂纹伤损的发生率,提出预防与控制对策:在焊接技术应用初期,应优化焊接参数与焊接过程;后期,严密监控裂纹伤损的发展状况,根据伤损程度制定缩短探伤周期、打磨车打磨、钻眼加固、伤轨更换等轻重缓急有别的检查、养护与修理(检养修)方案。相关分析研究思路可极大地提升闪光焊缝质量,降低裂缝伤损发生率,节约"检养修"成本,有力保障地铁行车安全,为国内其他地铁单位的运维管理提供值得参考借鉴的经验与做法。

Taking the flash weld crack damage on a Hangzhou subway line as the research object,the causes of the crack damage are analyzed,and through statistics of the occurrence frequency of the crack damage under different train lines,running directions,running frequencies and rail positions,the easy occurrence scenarios of the crack damage are made clear,and the countermeasure study is carried out.It is found that:1)Flash weld crack damage is most likely to occur in the circular curve section.From the perspective of the ratio of weld crack damage per kilometer and the ratio of line type which leads to reinforcement or replacement overhaul,it can be seen that the frequency of circular curve section is higher than that of transition curve section and straight line section.2)The upstream section of the line is more prone to crack damage than the downstream section.3)In unit time,the more frequent the train acts,the easier it is to cause crack damage.In order to reduce the incidence of flash weld crack damage,the prevention and control measures are put forward:In the initial stage of welding technology application,the welding parameters and welding process should be optimized.In the later period,closely monitor the development of crack damage,and formulate inspection,maintenance and repair schemes with different priorities,such as shortening the flaw detection cycle,polishing by grinding cars,drilling reinforcement and replacement of damaged rails,per the damage degree.The relevant analysis and research ideas can improve the quality of flash welds,reduce the incidence of cracks and injuries,save the cost of inspection maintenance and repair,and effectively ensure the safety of subway operation,which provides valuable experience and practices for the operation and maintenance management of other domestic subway units.