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应用有限元模拟和统计分析方法研究变形参数对直齿圆柱齿轮成形过程中变形和显微组织演变的影响。将有限元方法与显微组织演化模型相集成建立了基于浮动凹模设计的齿轮成形有限元模型。采用Gleeble热力模拟实验和定量金相分析技术获得镁合金高温流动应力曲线和动态再结晶模型。数值模拟和实验检验表明,由于齿轮形状复杂,且坯料与模具间存在接触摩擦,齿轮各部位变形和显微组织存在不均匀现象。变形温度降低或者变形速率增加,有利于获得平均晶粒尺寸细小的组织,但是变形和显微组织不均匀性增大,其原因和流动应力曲线特征有关。
The effects of deformation parameters on the deformation and microstructure evolution of spur gear during forming process were studied by finite element method and statistical analysis. The finite element method was integrated with the microstructure evolution model to establish a finite element model of gear forming based on floating die design. Gleeble thermal simulation experiments and quantitative metallographic analysis were used to obtain high temperature flow stress curves and dynamic recrystallization models of magnesium alloys. Numerical simulation and experimental tests show that due to the complicated shape of the gear and the contact friction between the billet and the mold, the deformation and the microstructure of the gear are uneven. Decreasing the deformation temperature or increasing the deformation rate is conducive to obtaining the microstructure with small average grain size, but the deformation and the microstructure heterogeneity increase due to the characteristics of the flow stress curve.