AZ31镁合金热轧开坯变形行为的有限元模拟

采用二维弹塑性大变形热力耦合有限元法(FEM),对半连续铸造AZ31镁合金热轧开坯过程第一道次进行模拟,分析变形区内轧件的应力场、应变场的分布及整个热轧过程中的温度场的变化规律.实验结果表明:在轧件变形区内,等效应力沿轧制方向逐渐增大,在中性面附近达到最大值54.1 MPa,随后又逐渐减小;靠近轧件表层σ_x为压应力,靠近心部为拉应力,在变形区σ_y主要为压应力,由表面到中心σ_y逐渐减小;等效应变沿轧制方向逐渐增大,在轧件出口处达到最大值0.253;在整个轧制过程中,轧件内部节点的温度变化缓慢,而表面节点的温度变化剧烈,轧制完成后,表面温度从500℃降低到467℃,中部温度从500℃升高到503.1℃,心部温度从500℃升高到502.2℃.

Finite element simulation of deformation in hot rolling process of AZ31 magnesium alloy

The first pass hot rolling of direct casting AZ31 magnesium was simulated by using two-dimensional elastic-plastic thermal-mechanical coupled finite element method (FEM).The distribution of stress field, strain field and temperature field of deforming region and the change of them during the whole process were analyzed.The results show that in the deforming zone the equivalent stress increases gradually along the direction of rolling and reaches the maximum value of 54.1 MPa nearby neutral face, then decreases gradually; σ_x near the surface is compressive stress, while it is tensile stress near the center, σ_x is mainly compressive stress, σ_x decreases gradually from surface to center.The equivalent strain increases gradually along the direction of rolling and reaches the maximum value of 0.253 at outlet of work piece; the surface temperature changes sharply during the rolling process, while the center temperature changes a little.After rolling, the surface temperature decreases from 500 ℃ to 467 ℃, while the temperature of the middle part increases from 500 ℃ to 503.1 ℃, and the center temperature increases from 500 ℃ to 502.2 ℃.