摘要
为研究35~40 t轴重钢轨和焊接接头的适应性,在美国交通技术中心加速测试试验线开展此轴重条件下实车验证试验,分析钢轨伤损变化规律。结果表明:68 kg·m^(-1) U78CrVH钢轨在通过总质量为254 Mt时曲线上股侧磨速率为0.0054 mm·Mt^(-1),在近200 Mt时出现1处轨头纵横裂型核伤,与钢质洁净度和轮轨关系相关,在科学养修条件下,U78CrVH钢轨适应35~40 t轴重铁路;由于闪光焊接接头硬度高于母材硬度,接头磨耗不显著,其出现疲劳伤损的主要原因是焊筋尖缺口处存在大的应力集中,综合考虑磨耗和疲劳伤损,闪光焊接接头适应35~40 t轴重铁路;铝热焊接接头出现明显的马鞍形磨耗和低塌,磨耗最大值为0.62 mm,其出现疲劳伤损的最小通过总质量为46 Mt,因初始硬度偏低,易产生磨耗和低塌,且为铸态组织,不适应35~40 t轴重铁路。为此,通过提高钢质洁净度、减少铝热焊接接头数量以及研究更适合的焊接方式,可提高大轴重条件下钢轨和焊接接头的服役寿命。
To study the adaptability of rail and welding joints with 35-40 t axle load,a real-vehicle verification test specific to that load was carried out in the United States through TTCI’s FAST program,to analyze the variation law of rail damage.Results show that the side wear rate on the upper track of 68 kg·m^(-1)U78CrVH rail was 0.0054 mm·Mt^(-1)with the total passing mass of 254 Mt.A longitudinal-transverse kidney-shaped crack appeared in the rail head was detected close to 200 Mt,which was related to the steel cleanliness and the wheel/rail relationship.Under condition-based maintenance,the U78CrVH rail was suitable for the heavy haul railway with 35-40 t axle load.The wear of the flash welding joints was less visible because the hardness of the joints was higher than that of the base metal.The main factor causing the fatigue damage was the higher stress concentration at the notch of the welded reinforcement tip.Considering the wear and fatigue damage comprehensively,flash welding joints were suitable for the 35-40 t axle load railway.Serious saddle-shaped wear and collapse appeared on thermite welding joints with the maximum wear of 0.62 mm.The fatigue damage of the joint appeared at its minimum total passing mass of 46 Mt.It was not suitable for the 35-40 t axle load railway due to its low initial hardness level,which would potentially lead to wear and collapse,and its ascast microstructure.Thus,improving the steel cleanliness,reducing the number of thermite welding joints,and developing more suitable welding methods could improve the service life of rail and welding joints with large axle loads.
作者
石彤
张银花
高振坤
冯子凌
周韶博
杨光
SHI Tong;ZHANG Yinhua;GAO Zhenkun;FENG Ziling;ZHOU Shaobo;YANG Guang(Metals and Chemistry Research Institute,China Academy of Railway Sciences Corporation Limited,Beijing 100081,China)
出处
《中国铁道科学》
EI
CAS
CSCD
北大核心
2022年第3期26-36,共11页
China Railway Science
基金
国家重点研发计划项目(2021YFB2601000)
中国铁道科学研究院集团有限公司科技研究开发计划项目(2021YJ213)。
作者简介
第一作者:石彤(1990-),女,河北保定人,助理研究员。E-mail:shitongthu@163.com;通讯作者:张银花(1965-),女,黑龙江虎林人,研究员。E-mail:nup@sina.com。
