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新型镍基粉末高温合金热挤压工艺有限元模拟与实验验证

Finite element simulation and experimental verification on hot extrusion of a novel nickel-base P/M superalloy

  • 摘要: 采用有限元模拟的方法对一种新型镍基粉末高温合金热挤压工艺进行了优化设计,分析讨论了几种主要参数对热挤压结果的影响,并通过热挤压实验验证了有限元模拟的可靠性。结果显示,在热挤压过程中,坯料初始温度对应力和温度影响显著,对应变速率和应变无明显影响;挤压杆速度是调整应力和应变速率的重要参数;采用较小的模角(小于45.0°)可以使应力、应变速率、应变和温度分布的均匀性大幅度提高,有效避免挤压棒材开裂和保证显微组织均匀性。由模拟结果推出的主要热挤压参数为:坯料初始温度1100℃,挤压杆速度40 mm·s-1,模角40.0°。将推荐的参数用于热挤压实验,结果证明了有限元分析结果准确,热挤压参数合理。

     

    Abstract: The finite element method was used to optimize the hot extrusion process of a novel nickel-based powder metallurgy superalloy in this paper, the influences of finite element parameters on hot extrusion were analyzed and discussed, and the reliability of finite element simulation was verified by extrusion experiment. The results show that, the initial temperature of billet has a significant effect on the stress and temperature during hot extrusion process, but has no obvious influence on the strain rate and strain. The speed of extrusion stem is an important parameter to control the stress and strain rate. The uniformity of stress, strain rate, strain, and temperature can be greatly improved by using smaller die angles (< 45.0°), which can effectively avoid the cracking of extrusion bar and ensure the uniformity of microstructures. The main hot extrusion parameters are recommended as following: the initial temperature of billet is 1100℃, the speed of extrusion ram is 40 mm·s-1, and the die angle is 40.0°. It is proved that the parameters applied to the hot extrusion experiment based on the finite element analysis are accurate and reasonable.

     

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