316L奥氏体不锈钢的高温流变行为

Flow behaviors of 316L stainless steel at high temperature

为建立能准确描述316L不锈钢流动特性的本构模型并合理制定其热成形工艺参数,采用圆柱试样在Gleeble-3500热模拟试验机上对316L奥氏体不锈钢进行等温压缩变形试验,研究316L不锈钢在变形温度为900℃～1 100℃、应变速率为0.01s-1～2s-1条件下的流变行为,建立其热变形本构方程。结果表明,变形温度和应变速率对流变应力有明显影响,流变应力随变形温度升高而降低,随应变速率的增加而升高。建立了材料常数α,n,lnA,及应变激活能Q与应变之间的非线性关系;316L不锈钢的热变形行为可用包含Arrhenius项考虑应变、应变速率及温度影响的本构方程描述。通过相关系数r、平均相对误差（AARE）对本构方程的准确性进行分析,结果表明,该方程可以准确预测316L不锈钢的高温流变行为。

The flow stress behaviors of 316L stainless steel were investigated by isothermal compression cylindrical specimens at 900 ℃ ~1100 ℃ and strain rate of 0.01 s-1 ~2 s-1 with Gleeble-3500 thermo-simulation machine to obtain the optimum forming parameters and establish the constitutive model of hot deformation . The results showed that deformation temperature and the strain rate had great effects on the flow stress . The flow stress decreased with the rising of the deformation temperature and in-creased with the increase of the strain rate .Material constants α, n ,lnA and activation energy Q were calculated as a function of strain . The constitutive equations of Arrhenius-type incorporating the effects of strain , strain rate and temperature have been de-veloped to model the hot deformation behavior of 316L stainless steel . The accuracy of the constitutive equations was evaluated by the correlation coefficient r and the average absolute relative error . The flow stress values of 316L stainless steel predicted by the proposed constitutive equations showed a good agreement with the experimental results ,which indicated that the developed con-stitutive equations could give a precise prediction for the flow stress of 316L stainless steel .