多拐曲轴镦挤成形过程轴向流动模拟分析与试验验证

目的 解决多拐曲轴镦挤复合成形过程中，轴向流动导致尺寸精度低的问题。方法 从坯料加热、成形过程、成形后冷却等全流程模拟出发，以建立镦挤成形装置运动学、成形过程热力学、曲轴材料本构模型、几何模型等为基础，建立有限元模型，分析产生轴向偏差的原因。结果 有限元模拟分析表明，坯料体积、飞边厚度是镦挤成形过程产生轴向流动的关键性因素，可以通过优化台阶轴毛坯几何形状，控制轴向异常流动。结论 试验表明，多拐曲轴的轴向流动得到有效控制，单拐轴向长度偏差控制在±1 mm，成品率提高至90%以上。

Axial Flow Simulation and Experimental Verification for Upsetting & Extrusion Process of Crankshaft

The paper aims to solve the issue of low dimensional accuracy caused by axial flow in upsetting & extrusion process of crankshaft. A finite element model was established according to simulation on the whole flow of heating, forming and cooling of blanks based on kinematics of upsetting & extrusion process device, thermodynamics of forming process, constitutive model of crankshaft material, geometric model, etc. to analyze causes of axial deviation. Based on simulation analysis of finite element, billet volume and flash thickness were the keys for axial flow in upsetting & extrusion forming. The abnormal axial flow might be controlled by optimizing the geometrical shape of blanks for step shaft. Experimental results show that the axial flow of the crankshaft is controlled effectively. The length deviation of single crank shaft is controlled within the range of ±1 mm and the qualified rate of crankshaft forging is up to 90%.