900MPa级析出强化钢高温变形行为

Hot deformation behaviors of 900 MPa grade precipitation strengthening steel

针对900MPa级析出强化型热轧高强钢，利用Gleeble．3800热模拟试验机研究其在变形温度为950～1150℃、变形速率为0．1～10S-I条件下的压缩变形行为。根据应力．应变曲线图获得峰值应力，并用双曲正弦方程描述热压缩变形过程中的试验钢峰值应力与Zener-Hollomon参数的关系。回归分析得到方程中变形激活能及其他材料变形参数，并对试验在高温条件下的流变应力本构方程并对其进行了验证。结果表明，采用该本构方程计算出的流变应力值与试验所得应力值非常接近，为估算成形时所需的最大载荷及设备选取提供参考。

Dealing with the 900 MPa grade hot rolled steel with precipitation strengthening, the hot deformation behavior was investigated with a compression test on Gleeble-3800 simulator with a temperature range of 950-- 1 150 ℃ and strain rate range of 0.01-10.0 s-1. The accurate values of peak stress were obtained from the stress-strain curve. A hyperbolic sine equation was employed to describe the relationship between the peak stress and Zener-Hollomon parameter, in which the activation energy of deformation and other constants were obtained using regression analysis. The flow stress constitutive equation by hot compression was obtained and it was tested and verified. The results show that the flow stress predicted by the proposed models agrees well with the experimental results. This can provide reference for the limited load during the process of forming and for the choosing of equipment.