进口淬火钢轨的性能及应用研究

Study on the Service Performance of the Imported Quenched Rails

针对20世纪90年代中期我国进口并铺设使用的日本、法国、奥地利及俄罗斯淬火钢轨,进行性能和应用状况分析,研究钢轨出现滚动接触疲劳缺陷的原因,提出解决措施。研究结果表明,日本、法国、奥地利的钢轨淬火工艺为离线欠速淬火工艺,仅对轨头进行加热和冷却处理,从而得到较高的强度和硬度。这种钢轨虽然在小半经曲线上表现出较高的抗磨耗性能,但在直线段上当通过总重达到4～5亿t.km时,钢轨踏面会出现隐伤、斜裂纹、剥离掉块等较严重的滚动接触疲劳缺陷;俄罗斯的钢轨淬火工艺为淬火+回火工艺,钢轨全断面经过加热和冷却处理,虽硬度和强度略低,但因其不同的廓面形状和较好的轮轨匹配关系,使得滚动接触疲劳伤损较轻;进口淬火钢轨出现的斜裂纹一般形成在轨距角处,与行车方向大致成40°～50°角并向行车方向发展。疲劳裂纹是由材料的棘齿形滞回效应引起的,并在高的接触应力下扩展。因此定期打磨钢轨和使用新廓面钢轨是解决滚动接触疲劳问题的有效方法。

The service performance of heat-treatment rails which produced by NSC and France and Voestalpine AG and Russia in the middle of 1990s are researched in this paper, RCF （rolling contact fatigue） of these heat-treatment rails are discussed, some adaptive suggestions are put forward. The results show that the heat-treatment way of NSC and France and Voestalpine AG rails is slack quenching, rails has a better property of resist-wear at small radius line, if NSC and France and Voestalpine AG heat-treatment rails are laid at straight line, RCF such as squat and spalling and head crack will appear on rail tread when the accumulative passing gross weight of rail is 400-500 Mt · km Russia＇s rail quenching process is quenching and tempering process, the whole section of the rail been heated and cooled, though slightly lower hard- ness and strength, but because a different profile in the shape and better match between wheel and rail, it makes the damage of RCF more minor. Head crack usually occurs at the gauge corner, and develops along 40-50 angle direction of train running. Fatigue crack is brought by the ratchet effect, and spreads by high contact stress. Regular grinding and new rail profile are effective way to solve RCF.