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为了研究铸态P91耐热合金钢的高温变形流变特性,建立铸态P91耐热合金钢高温流变应力本构方程,采用Gleeble-3500热模拟实验机对铸态P91耐热合金钢进行等温热压缩实验,研究了变形温度为900~1200℃、应变速率为0.01~5 s-1、变形量为60%条件下的热变形行为。研究结果表明,随着变形温度的升高和应变速率的降低,动态再结晶现象越容易发生,流变应力显著降低,曲线由加工硬化型向动态回复及动态再结晶型转变。在双曲正弦修正的Arrhenius型方程及Zener-Hollomon参数的基础上,考虑真应变对流动应力的影响,建立了铸态P91耐热合金钢的流变应力模型及本构方程。误差分析表明,所建立的本构方程具有良好的精度。
In order to study the high temperature deformation rheology of as-cast P91 heat-resistant alloy steel, the constitutive equation of high temperature flow stress of as-cast P91 heat-resistant alloy steel was established. The cast P91 heat-resistant alloy steel was treated with Gleeble-3500 thermal simulation machine The thermal deformation experiments were carried out to study the thermal deformation behavior under the condition of deformation temperature of 900 ~ 1200 ℃, strain rate of 0.01 ~ 5 s-1 and deformation of 60%. The results show that with the increase of deformation temperature and strain rate, the dynamic recrystallization phenomenon occurs more easily and the flow stress decreases remarkably. The curve changes from work hardening to dynamic recovery and dynamic recrystallization. Based on the hyperbolic sinusoidal modified Arrhenius equation and the Zener-Hollomon parameter, the flow stress model and constitutive equation of as-cast P91 heat-resistant alloy steel are established considering the effect of true strain on the flow stress. Error analysis shows that the established constitutive equation has good accuracy.