大秦铁路重车线U78CrV钢轨锈蚀断裂原因分析

针对大秦铁路重车线U78CrV钢轨锈蚀断裂的问题,分析了钢轨锈蚀的原因,然后对不同材质钢轨的耐蚀及抗断裂性能进行试验研究,对钢轨断裂原因进行了探讨。试验结果表明:隧道漏水会导致局部钢轨轨底锈蚀;冬季使用含有Cl-的防冻液则会加剧钢轨的锈蚀;曾出现过断轨的U78CrV钢轨和其他材质钢轨相比有着相对较差的耐应力腐蚀性能及抗断裂性能;钢轨轨底在环境因素的影响下发生锈蚀并形成锈蚀坑,在钢轨内部拉应力(温度应力及残余应力)以及大轴重列车通过钢轨时产生的动弯曲应力的作用下,轨底锈蚀坑会成为应力集中点而形成裂纹源,当钢轨材质抗断裂性能不足时裂纹扩展较快,最终导致断裂。

Cause Analysis of Rust Corrosion and Fracture of U78CrV Rails in Datong-Qinhuangdao Heavy Haul Railway

Aiming at rust corrosion and fracture of U78CrV rails in Datong-Qinhuangdao heavy haul railway,this paper analyzed the causes of rail rust corrosion,then experimental study on corrosion resistant performances and anti-fracture performances of different materials was carried out,and the fracture causes were discussed. The test results show that the water in tunnels can cause corrosion of rail base,and the use of antifreeze in winter which containing Cl^- makes the situation even w orse.C ompared with other materials,the U78CrV rail which ever broken has relatively poor stress corrosion resistant performance and anti-fracture performance. Corrosion pit caused by environmental factors mainly forms in the rail base.Under the actions of the internal tensile stress( both temperature stress and residual stress) and the dynamic bending stress when the heavy haul train passes by,the pit will become a stress concentration point and then become into a crack. If U78CrV rail hasn’t suff icient anti-fracture performance,the cracks extend rapidly and lead to a break eventually.