Abstract

A simple mathematical model has been developed which describes the flow curve behavior up to the peak true stress or a true strain of 0.6 in unstable austenite. The hot working behavior was analyzed by compression tests over a temperature range of 750–1000 °C and at strain rates of 0.1–50 s⁻¹. The constitutive behavior focused on the interaction between work hardening and dynamic softening attributed to recovery, recrystallization and dynamic austenite to ferrite transformation. This model extends the application of the well-established Estrin and Mecking (EM) work-hardening model in the unstable austenite region. The work hardening is countered by softening kinetics, represented in this model by JMAK-type expressions for both dynamic transformation and recrystallization. The predicted results correlate well with experimental results in VN and Nb-Ti microalloyed steels.

中文翻译：

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VN和Nb-Ti微合金钢在热压缩变形过程中的高温流动应力建模

摘要

已开发出一个简单的数学模型，该模型描述了不稳定奥氏体中直至峰值真实应力或真实应变为0.6的流动曲线行为。通过压缩测试在750–1000°C的温度范围内以及0.1–50 s ^-1的应变速率下分析了热加工行为。本构行为集中于工作硬化和动态软化之间的相互作用，这归因于恢复，再结晶以及动态奥氏体到铁素体的转变。该模型扩展了已建立的Estrin和Mecking（EM）工作硬化模型在不稳定奥氏体区域中的应用。加工硬化被软化动力学抵消，该动力学在该模型中由JMAK型表达式表示，用于动态转变和重结晶。预测结果与VN和Nb-Ti微合金钢的实验结果很好地相关。