型钢热轧开坯过程金属变形分析

Deformation analysis of hot rolling cogging process of shape-metal

型钢热轧开坯是高温坯料在低温轧辊作用下的金属变形过程,高温下金属材料的变形抗力随温度和应变速率变化明显,而且变形中塑性功和接触面摩擦以及坯料和轧辊间的热传导、和空气对流换热、辐射散热等,将导致坯料温度场的变化。因此,利用有限元法分析变形过程时,必须同时计算温度场和位移场。采用Mises屈服准则和弹/粘塑性材料模型,推导了采用等向强化假设的材料物性关系中的塑性矩阵、温度修正矩阵、应变速率修正矩阵的具体表达式。分析了多道次H型钢孔型轧制的开坯过程,总结了坯料在孔型中的变形规律,通过和H型钢生产现场数据的对比验证了结果的准确性。

The yield stress of metal at high temperatures varies with the temperature changing. The heat generation by plastic work and friction work of the contact region, the heat conduction between hot stock and rollers, the convection with the air, the radiation with the surroundings effect the temperature filed of hot stock. So, the displacement and temperature must be solved simultaneously in order to analyze the strain, stress and temperature field. Model the metal with elastic/viscosity-plastic and adopt the Mises yield criteria, the plastic matrix, the temperature amendatory matrix, and the plastic strain rate amendatory matrix were proposed. A multi-pass H-beam cogging progress was analyzed. The deformation characters of the metal in the caliber were summarized, and the accuracy of the results were proved by the comparison with those proposed by the product line.