热轧过程微观组织演变的数值预报与试验研究

NUMERICAL PREDICTION AND EXPERIMENTAL RESEARCH OF MICROSTRUCTURE DEVELOPMENT DURING HOT ROLLING

对于热力耦合大变形问题 ,构造了同时求解变形和温度的热弹塑性变分原理和相应有限元法 ,并与金属微观组织演变数学模型相结合 ,提出了热变形过程微观组织的数值预报方法。针对再结晶动力学方程和晶粒长大方程对时间和温度的高度非线性 ,定义了一个经温度补偿的适用于变温过程的等效时间 ,解决了变温状态下对时间的叠加问题。作为应用 ,模拟了H型钢热轧过程的微观组织演变 ,并相应地进行了试验研究。预报值与实测值吻合良好 。

For the thermomechanical coupled large deformation problems,a thermal elastic plastic variational principle and corresponding finite element method are developed.Integrating the method with mathematical model of microstructure evolution,a numerical method to predict the microstructure during hot deformation is proposed.In regard to the highly non linearity of the equations for recrystallisation fraction and grain growth,an effective time compensated by temperature is defined,by which the time additivity is reasonable and suitable for temperature varying conditions.As an application,the microstructure evolutions of H team during hot rolling are simulated,and corresponding experimental research are performed.The coincidence of the predicted grain sizes with measured ones shows that the method is able to?successfully predict the microstructure of metals after hot deformation.