导流模和分流模金属挤压流动成形的数值模拟

建立了铝合金导流模和分流模挤压分析模型,利用有限体积法(FVM)分别对导流模和分流模模具在铝合金挤压过程中坯料的应力分布和速度场分布进行了比较和分析,发现坯料应力的分布与工作带高度的设定、出材流动是否均衡没有直接的联系,而工作带的调节对改善金属的流动有一定的作用.针对型材出口处的金属流动均匀性,提出了一个判定能否获得稳定合格型材的依据.计算出口型材的标准速度场偏差(SDV),当SDV随时间增加逐渐减少,并且其收敛值小于一个临界值时,认为能够获得稳定合格的型材.

Numerical Simulation of Metallic Flow Forming via Extrusion in Pocket and Porthole Dies

Two models to analyze the aluminium alloy extrusion in the pocket and the porthole dies are respectively established, and the distributions of stress and velocity field of the billet respectively in the two dies during the extrusion are then compared and analyzed using the finite volume method (FVM). The results indicate that the stress distribution of the billet is not directly related to the height of the die bearing and the flow equilibrium of the material, while the adjustment of the die bearing plays a certain role in the improvement of metal flow. Aiming at the flow equilibrium of the material at the outlet, a criterion is then proposed to judge whether stable qualified products can be obtained by the extrusion. Moreover, the standard deviation of the velocity field (SDV) at the outlet is calcula-ted. The results show that, when the SDV decreases with the increase in time to less than a critical convergence va-lue, stable qualified products can be obtained.