16Mn钢热变形流变应力模型及晶粒大小

MATHEMATIC MODEL OF FIOW STRESS AND GRAIN SIZE OF 16Mn STEEL UNDER HOT DEFORMATION

利用热变形模拟试验装置,在850～1150℃变形温度、0.1～60 s^(-1)变形速率的条件下16Mn钢单道次压缩试验得到热变形的流变应力模型为σ=4.4ε^(0.158)ε^(7.22×10^(-5T))exp(4383/T)形变激活能Q为366 kJ/mol,应力指数n为9.56。>900℃出现明显的动态再结晶。应力—应变曲线呈单蜂状;<850℃出现动态回复。流变应力σ、峰值应力σ_p、再结晶晶粒大小与Z参数呈线性关系σ_(ε(?)0.2)=3.67Z^(0.098);σ_p=2.9Z^(0.11);D_r=105.13Z^(-0.046)。

The isothermal single-stage compression test of 16Mn steel has been carried cut by using Thermecmastor-Z Simulator at the deformation temperature of 850℃～1150℃, strain rate of 0.1 s^(-1)～60s^(-1). The mathematic model of the flow stress under hot deformation has been obtained:σ=4.4ε^(0.138)ε^(7.22×10^(-5))Texp(4383/T) The deformation activation energy of 16Mn steel is 366 kJ/mol and the stress index is 9.56. It is shown that dynamic recrystallization occurs above 900℃, and the ture stress-strain curves show single peak. Below 850℃, only dynamic recovery appears. The dependence of flow stress σ(ε=0.2) or the peak stress σ p on Z parameter is as follows:σ(ε=0.2)=3.67Z^(0.098)σ_p=2.9Z^(0.11) The dependence of dynamic recrystallized austenite grain size on Z parameter is in accordance with the following formula: σr=105.13Z^(-0.046)