稀土重轨钢BNbRE的流动应力模型研究

Study on Flow Stress Model of Rare Earth Heavy Rail Steel BNbRE

以稀土重轨钢BNbRE为研究对象,利用Gleeble-1500D热模拟机对稀土重轨钢BNbRE高温压缩试验,测定BNbRE在不同热加工条件下的应力应变曲线,根据测得的数据,研究变形温度、应变速率和变形程度对其流动应力关系,并在金相显微镜下观察部分工艺下的微观组织,分析变形工艺对材料晶粒尺寸的影响。确定了稀土重轨钢BNbRE的流动应力主要影响因素及数学模型,通过测得数据利用MATLAB进行多元非线性回归,建立流动应力数学模型;将理论计算与实测值进行检验并进行误差分析,证明该模型得到的预测值与实测值具有较高吻合度,且在预测大于6%的变形量和较快应变速率时,得到的流动应力有更高精度、更好的拟合特性,可为该钢种在实际应用中的数值模拟及工艺参数计算提供理论计算依据。

The high temperature compression test on rare earth heavy rail steel BNbRE was carried out by Gleeble-1500 D thermal simulator.The stress and strain curves of BNbRE under different hot working conditions were measured.Based on the measured data,the relationship between deformation temperature,strain rate and degree of deformation was studied.The microstructure was observed under a metallographic microscope,and the influence of the deformation process on the grain size of the material was analyzed.The main influencing factors and mathematical models of the flow stress of rare earth heavy rail steel BNbRE were determined.The mathematical model of flow stress was established by using MATLAB to perform multivariate nonlinear regression.After comparing the theoretical value with the measured value and analyzing the error,it is concluded that the predicted value obtained by the model is in good coincidence with the measured value.And when predicting deformation was hign than 6%and strain rates were high,the resulting flow stress had higher precision and better fitting characteristics.It can provide theoretical calculation basis for the numerical simulation and process parameter calculation of the steel in practical applications.