低碳9Ni钢的动态再结晶数学模型

利用MMS-300热模拟实验机对9Ni钢进行了温度范围为800～1150℃、应变速率范围为0.05～1s-1的单道次压缩实验.通过应力-应变曲线研究了9Ni钢的动态再结晶规律,采用硬化率-应力(θ-σ)曲线较精确地确定了动态再结晶的临界条件和峰值应力应变.采用回归法确定了双曲线本构方程中的材料常数和动态再结晶激活能(269kJ/mol),并建立了临界应变、峰值应变和峰值应力与无量纲参数Z/A之间的关系.利用Avrami方程和应力应变曲线建立了9Ni钢动态再结晶动力学模型.

Mathematical Modeling for Dynamic Recrystallization Behavior of Low-Carbon 9Ni Steels

The dynamical recrystallization (DRX) behavior of 9Ni steel was investigated via a single-pass reduction test on a MMS-300 simulator over the temperatures range from 800 to 1 150 ℃ at the strain rates range from 0.05 to 1 s~(-1). The critical conditions for DRX and peak stress/ strain were determined by the relationship between work hardening rate (θ) and flow stress (σ). The material parameters in the hyperbolic sine constitutive equation were determined with regression analysis, and the DRX activation energy was thus obtained to be 269 kJ/mol. The relationship between critical strain, peak strain/stress and the dimensionless parameter Z/A were established by linear regression. Mathematical model of the DRX kinetics was developed for low-carbon 9Ni steel by using Avrami equation and stress-strain curses.