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某地铁线路通车一段时间后,在钢轨轨头踏面出现点状伤损。调查了产生轨头踏面点状伤损的线路情况,并取样进行理化检验分析,钢轨踏面点状伤损部位表面含有锌元素,表面锌质量分数达到95%以上,基体组织为马氏体加少量贝氏体和少量残余奥氏体。分析表明高温金属液滴粘附在钢轨踏面,造成钢轨踏面局部金属被加热,导致其奥氏体化,然后迅速冷却,组织转变成马氏体加少量贝氏体和少量残余奥氏体,从而形成踏面点状伤损。若在地铁线路施工过程中,对钢轨进行保护可避免类似伤损的产生。
Some subway lines opened to traffic after a period of time, the rail head tread surface punctate injury. Investigate the situation of point-like wounds on rail treads and take samples for physical and chemical analysis. The surface of spotted rail treads contains zinc, the surface zinc content reaches more than 95%, and the matrix microstructure is martensite plus a small amount Bainite and a small amount of retained austenite. The analysis shows that the hot metal droplets adhere to the rail tread, causing the local metal on the rail tread to be heated, resulting in austenitization and rapid cooling. The microstructure is transformed into martensite plus a small amount of retained austenite and a small amount of retained austenite Formation of tread point damage. If the subway line in the construction process, the protection of the rail to avoid similar injuries.