锻压技术

铸态Q345E钢的本构方程及动态再结晶行为

英文标题：Constitutive equation and dynamic recrystallization behavior for as-cast Q345E steel

作者：孔晓寒陈慧琴刘建生焦永星李国栋

分类号：TG115.21；TG142.7

出版年,卷(期):页码：2020,45(11):199-204

摘要：

以风电法兰用铸态Q345E钢为研究对象，利用Gleeble-1500D热模拟实验机，在变形温度为950~1250 ℃、应变速率为0.001~1 s-1、变形量为60%的条件下进行单道次热压缩实验，获得真应力–真应变曲线，并分析不同变形条件下该材料的热变形行为。结果表明：铸态Q345E钢在变形过程中，存在两种软化机制，变形温度小于1000 ℃、应变速率在0.001~1 s-1范围时，流动应力曲线均呈动态回复的软化特征；变形温度为1100 ℃及以上时，材料的主要软化机制为动态再结晶，且与发生动态再结晶的峰值应变相比，峰值应力对变形条件的改变更为敏感。基于Arrhenius双曲正弦函数，计算得出该材料的本构方程，求得其动态再结晶发生的临界应变，建立动态再结晶动力学模型。

For as-cast Q345E steel used for manufacturing wind-power flanges, the single-pass thermal compression experiments were conducted by thermal simulation test machine Gleeble-1500D under the deformation temperatures of 950-1250 ℃, the strain rates of 0.001-1 s-1 and the deformation amount of 60%, and the true stress-true strain curves were obtained. Then, the thermal deformation behaviors of material under different deformation conditions were analyzed. The results show that the deformation process of as-cast Q345E steel includes two kinds of softening mechanisms. When the deformation temperature is less than 1000 ℃ and the strain rate is in the range of 0.001-1 s-1 , the flow stress curves show the softening characteristics of dynamic recovery. However, when the deformation temperature is 1100 ℃ or above, the main softening mechanism of material is dynamic recrystallization, and comparing with the peak strain at which the dynamic recrystallization occurs, the peak stress is more sensitive to changes in deformation conditions. Furthermore, according to the Arrhenius hyperbolic sine function, the constitutive equation of as-cast Q345E steel is constructed, the critical strain for dynamic recrystallization is determined, and the kinetic model of dynamic recrystallization is constructed.

基金项目：

国家自然科学基金资助项目(51775361)

孔晓寒(1993-)，男，硕士研究生 E-mail：616526863@qq.com；通讯作者：陈慧琴(1968-)，女，博士，教授 E-mail：chenhuiqin@tyust.edu.cn

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