火车用C级钢的高温流动应力

High temperature flow stresses in C-grade steel for train components

C级钢因其优越的机械性能而广泛应用于火车车轮、车钩等重要零部件上。该材料零部件通常经热锻成形,因此对该材料在高温下的流动应力进行研究具有重要意义。该文采用Gleeble热力学模拟机对C级钢在温度为1 050～1 250℃、应变速率为0.01～10 s-1条件下的流动应力进行测试,获得C级钢的流动应力数据以及C级钢在不同热变形条件下的峰值及稳态流动应力。实验结果预测了C级钢存在动态再结晶现象,得到了变形温度、应变速率和变形程度对C级钢流变应力的影响规律。基于Sellers-Tegart方程拟合本构参数,包括应力水平参数、应力指数、变形激活能和结构因子,建立了C级钢的本构关系式,可作为C级钢零部件热成形加工工艺选择和参数确定的依据,同时也可作为C级钢零部件锻造工艺数值模拟的基础数据。

C-grade steel is widely used for train wheels,train couplings and other parts,some of which are subjected to high temperatures and plastic deformation.Thus,the high temperature mechanical properties are important.This paper reports experiment data taken on a Gleeble thermo-mechanical simulator for the strain-stress curves for various deformation conditions.The results indicate that dynamic recrystallization occurs during high temperature deformation.The flow stresses for different conditions were analyzed to relate the flow stress,temperature and strain rate in a Sellers-Tegart equation.This stress model for C-grade steel at high temperatures can be used to design hot processing techniques.The data can be used to validate numerical simulations of the forging of C-grade steel parts.