铁道货车车轮CL60钢在450℃时的低循环疲劳行为

Low cycle fatigue behaviours at 450 ℃ of CL60 steel for railway freight wheel

铁道货车车轮产生损伤失效的主要原因是承受了复杂的热载荷和机械载荷的联合作用,而高温低循环疲劳是车轮踏面区域产生损伤的重要机理之一.针对铁道货车车轮CL60钢进行了450℃时的高温低循环疲劳实验.研究发现:在整个循环过程中,应力-应变关系曲线的变化趋势基本一致;随着循环周次的进行,拉压应力峰值呈现出连续的降低态势,压应力峰值减幅略大于拉应力峰值减幅,表现了低循环疲劳的典型特性;试样断口上出现了较为严重的氧化现象,断口裂纹扩展以穿晶为主.

The main reason resulting in the damages of railway freight wheel is due to the interactive ef- fects of thermal and mechanical load, which belongs to High-temperature low cycle fatigue （LCF）. In this paper, High-temperature LCF experiments of CL 60 steel for freight wheel were conducted at 450℃. The results show that the stress-strain relation curves keep a steady trend during the whole cy- cle process. The peak value of tensile and compressive stress is successively decreasing along with the cycle period, and the compressive stress decreases more than the tensile stress, which reflects typical characteristics of LCF. The fracture of the specimen is covered by an oxidation film, and the cracks on the fracture are mainly in the intergranular form.