朔黄铁路曲线下股热处理钢轨剥离伤损成因分析  

Analysis on the Formation Cause of Spalling and Damage of the Heat-Treated Low Rail on Shuohuang Railway Curve

作　　者：陈朝阳[1] 张银花[1] 刘丰收[2] 周清跃[2] 

机构地区：[1]中国铁道科学研究院金属及化学研究所,北京100081 [2]中国铁道科学研究院铁道科学研究发展中心,北京100081

出　　处：《中国铁道科学》2008年第4期28-34,共7页China Railway Science

基　　金：国家自然科学基金资助项目(50271048)

摘　　要：对朔黄铁路的5段75 kg.m-1的U75V钢轨性能进行检验,分析伤损钢轨裂纹附近的性能。分析表明:U75V热轧钢轨母材的组织和硬度均合格,但U75V热处理钢轨的淬火层深度及横断面硬度均未满足TB/T 2635—2004的要求;显微硬度数据显示,在钢轨横断面存在较薄的硬化层;曲线下股钢轨踏面中心裂纹的深度在1.3 mm左右,并呈现不同程度的剥离掉块,与钢轨硬度分布特征有关;裂纹萌生于钢轨轨头表面塑性流变层内,裂纹起始的发展与列车运行方向成一定的锐角,出流变层后基本以垂直方向朝轨头内部扩展,到一定程度后,裂纹呈鱼钩状,以大致与列车运行的相反方向朝轨顶面扩展,最终导致剥离掉块。建议使用符合标准的热处理钢轨;对曲线钢轨及时进行大机打磨;采取措施,降低纵横向蠕滑力。The performance of 5 segments of 75 kg· m^-1 U75V rail on Shuohuang Railway has been inspected to analyze the performance of the damaged rail near the crack. Analyses show that the microstructures and hardness of the parent metals of U75V hot-roll rail are eligible. Whereas, both the quenching layer depth and the transect hardness of U75V heat-treated rail fail to meet the requirements of TB/ T2635-2004. The results of rail micro-hardness show that there is a thin hardened layer in rail transect. The depth of the crack in the middle of the curve low rail tread is about 1.3 mm, and there are much different spalling that is related with the distribution characteristics of rail hardness. Cracks initiate from the plastic flow layer of rail head surface. There is an acute angle between the spread of crack initiation and the direction of train running. Cracks spread basically along vertical direction towards rail head when cracks are out of the plastic flow layer. When the cracks grow to certain extent, they manifest barb shape and spread approximately along the right-about with train running direction towards rail top. Finally, spalling is formed. In order to reduce the spalling of low rail at which heat-treated rail is used, and eligible heat- treated rail should be used and grinding also should be implemented at curve rail, and the transverse and longitudinal creepage force of rail should be decreased.

关 键 词：铁路曲线 75kg·m^-1热处理钢轨 裂纹 剥离掉块 

分 类 号：U213.42[交通运输工程—道路与铁道工程]