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针对外星轮热挤压成形性能波动,模具杆部过渡圆角区磨损严重的问题,对关键模具结构和挤压工艺参数开展优化研究。基于有限元数值模拟仿真,结合析因试验分析首先得到影响磨损和填充的关键参数及其影响方向。随后对核心参数构造代理模型替代有限元机理模型,用于磨损和填充性能的数值预测。并使用线性加权和法将所得近似模型转化为单目标函数,耦合遗传算法进行全局寻优。计算发现,当入口斜度y=30°,根部圆角a=18.6 mm,杆部圆角b=5 mm,模具硬度HRC60,摩擦因数m=0.1,挤压速度v=10 mm/s,模具预热温度T=300℃,坯料初始温度t=1 180℃时,在保证锻件填充完全的前提下可获得模具最大磨损量的显著降低,模具寿命较初始提高约2 100件。最后通过仿真和生产试验验证了优化结果的正确性。
In allusion to the fluctuation of hot extrusion forming performance and the severe abrasion of the fillet area of the mold stem, the key mold structure and extrusion process parameters are optimized. Based on the finite element numerical simulation and the analysis of factorial analysis, the key parameters influencing wear and filling and their influence directions are obtained first. Subsequently, the core parameters are used to construct the proxy model instead of the finite element model for numerical prediction of wear and filling properties. The linear approximation method is used to convert the approximate model into a single objective function, and the coupled genetic algorithm is used for global optimization. The calculated results show that when the inlet gradient is y = 30 °, the root radius is a = 18.6 mm, the radius of the rod is b = 5 mm, the die hardness is HRC60, the friction coefficient is m = 0.1 and the extrusion speed is v = 10 mm / Preheating temperature T = 300 ℃, the initial temperature of the blank t = 180 ℃, the maximum wear of the die can be significantly reduced under the premise of ensuring forging full filling, and the die life is about 2 100 pieces higher than the original. Finally, the correctness of the optimization result is verified through simulation and production test.