高速铁路新材料

对青藏铁路格拉段正线与站线在役钢轨，现场测试了钢轨硬度、廓形、焊接接头平直度等数据，调研分析了钢轨母材与焊接接头磨耗、轻伤、重伤、折断等服役情况，获得了钢轨服役现状。结果表明：用于小半径曲线的U71Mn热轧钢轨磨耗速率较快，硬度与强度等级不足，选用在线热处理钢轨U75VH可明显提高钢轨耐磨寿命。格拉段站线钢轨的轻伤数量明显高于区间正线钢轨，鱼鳞伤与剥离掉块在上股钢轨与道岔钢轨中较为常见，钢轨擦伤与机械碰伤占轻伤总数的27%。道岔钢轨母材重伤率是正线钢轨母材的3倍，焊接接头的重伤主要发生在铝热焊接头，铝热焊接头重伤率是气压焊接头的5倍，铝热焊接头的主要重伤类型为内部核伤、气孔、夹渣、夹砂。

In the main line and station line of Golmud-Lhasa Qinghai-Tibet railway, the service conditions of wear, minor injury, serious injury and fracture of rail base metal and welded joint were investigated by means of investigation, test and analysis. Data such as rail hardness, profile, and straightness of welded joints were tested on-site, and the statistical analysis was performed on these data to obtain the current status of rail service. The results show that the U71Mn hot-rolled steel rails used for sharp curves present a faster wear rate and insufficient hardness. The selection of U75VH on-line heat treatment rails can significantly improve the wear resistant life of the rails. The number of minor injuries of the rails on station line of Golmud-Lhasa section is significantly higher than that of the rails on the main line in this section. Rail corner fine cracks and shelling defects are more common in the high rail of the curve and the turnout, and wheel burns and mechanical injuries account for 27% of the statistical minor injuries. The serious injury rate of the turnout rail base material is 3 times as much as the main rail base material. The main serious injury of welding joint is thermite welding, which is 5 times that of pressure gas welding. The main serious injury forms of aluminothermic welded joints were internal transverse defect, porosity, slag inclusion, and sand inclusion.