重载铁路用U77MnCr钢轨的试验研究

Research on the Performances of U77MnCr Used for Heavy-haul Railway

研究目的：含Cr低合金钢轨在国外重载铁路已得到了成功应用，而我国重载铁路在含Cr低合金钢轨使用方面还是一个空白。本文对U77MnCr钢轨的母材性能、焊接性能进行试验研究，并跟踪研究其在重载铁路上铺设的使用情况。研究结论：U77MnCr钢轨母材材质具有很好的纯净度和良好的强韧性，适合铺设在重载铁路的直线地；U77MnCr钢轨不含贵重的钒合金，只加入较便宜的0．25％～0．40％的铬合金，强塑性较好，具有很好的性价比；U77MnCr钢轨母材具有良好的焊接性能，焊接接头具有自硬化性能，正火后无需进行喷风冷却，轨顶面的硬度就可与母材的硬度匹配；U77Mncr钢轨具有良好的抗接触疲劳伤损能力和焊接性能，对提高重载铁路钢轨使用寿命有一定的作用。

Research purposes： The heavy - haul railway of foreign countries has successfully used the low - alloy rails containing Cr, but there was no application of low - alloy rails containing Cr in Chinese heavy haul railway in the past. The parent metals and welding of U77MnCr rail as well as the application of U77MnCr rail are studied in this paper. Research conclusions：The parent metals of U77MnCr rail is suitable for being used in the straight section of heavy - haul railway because of its high purity and good strength - toughness, has a perfect cost performance because it only contains the cheap chrome alloy of 0.25% - 0.40% with good elasticity and does not contain the treasure vanadium alloy, has a good welding performance with self - harden ability of welding joints, so it does not need air cooling after normalizing and the toughness of the rail top surface matches the toughness of the parent mental, and has a good fatigue resistance that can prolong the service life of the rail on heavy - haul railway.