大棒材热轧工艺的数值模拟

Numerical simulation of hot rolling of large bars

大棒材轧制属于高温大变形塑性成形过程,为了研究轧制过程中轧件温度场、应变场及微观组织演变的规律,在热模拟实验的基础上建立了大棒材初轧道次热-力-组织耦合的有限元模拟模型。模拟结果显示,轧制过程中轧件由于发生再结晶使晶粒得到细化,初轧完成后,轧件平均晶粒尺寸由芯部到表层逐渐减小;由于大棒材初轧过程中轧件芯部变形量较小,不利于轧件芯部孔隙性缺陷的压实,因此提高热轧连铸坯的芯部致密度是改善大棒材芯部质量的重要措施之一。

Large bar rolling is a high-temperature,large-deformation plastic forming process.To study the evolution of the temperature field,strain field and microstructure of the rolling workpiece in the rolling process,a thermal-mechanical and microstructure coupling FE model of large bar during blooming was established on the basis of thermal simulation experiments.The numerical simulation reveals that fine grain size is obtained due to recrystallization,and the grain size is reduced from center region to surface layer in the rolling workpiece.The deformation in the center region of the workpiece is small during large bar blooming,which is disadvantageous to compaction of porosity defects,and increasing the center density of the continuous casting blank used for large bar rolling is one of the important methods to improve the quality of the large bar.