U75VG钢轨钢与温度相关的循环塑性变形行为

采用单轴拉伸试验和循环塑性变形试验研究了U75VG钢轨钢在不同温度(25,300,600℃)时的单轴拉伸性能以及循环塑性变形行为。结果表明:在应变控制循环载荷下,25℃时U75VG钢轨钢表现出循环软化特性,300℃时在动态应变时效作用下表现出循环硬化特性,600℃时动态应变时效作用消失,表现出更明显的循环软化特性;在应力控制循环载荷下,U75VG钢轨钢在不同温度下均表现出明显的棘轮行为特征,棘轮应变速率随平均应力或应力幅的增加而增大,在300℃时棘轮应变演变呈现出准安定状态,在600℃时随着平均应力或应力幅的增加棘轮应变加速增大。

Temperature-Dependent Cyclic Plastic Deformation Behavior of U75VG Rail Steel

The uniaxial tensile property and cyclic plastic deformation behavior of U75VG rail steel were studied by uniaxial tensile tests and cyclic plastic deformation tests at different temperatures(25,300,600℃).The results show that the U75VG rail steel presented initial cyclic softening characteristics under strain-controlled cyclic load at 25℃,and initial cyclic hardening characteristics at 300℃ by the dynamic strain ageing.The dynamic strain ageing effect disappeared and the cyclic softening feature was obvious at 600 ℃.The U75VG rail steel exhibited obvious ratcheting behavior characteristics under stress-controlled cyclic load at different temperatures.The ratcheting strain rate increased with the increase of mean stress or stress amplitude.The ratcheting strain rate was close to the stable state at 300℃,and increased rapidly with the increase of mean stress or stress amplitude at 600℃.