不同压制工艺对粉末冶金制品性能影响的有限元模拟

利用MSC/MARC有限元分析软件对金属粉末压制过程进行模拟分析.采用基于更新拉格朗日方法的热-力耦合分析不同工艺条件(温度、摩擦条件和压制方式等)对压坯性能的影响规律,同时对压制过程中的力学特征(压制力、脱模力、侧压力和应力分布等)进行分析.结果显示,摩擦条件是影响压坯密度大小及分布的关键因素,通过采用双向压制方法可以有效地改善单向压制压坯密度分布不均、差值较大的现象.温度的提高有利于提高粉末颗粒的塑性变形能力,但效果不明显.另外,由于温度影响润滑剂润滑性能,因此在制定压制工艺时需考虑温度对压坯性能的影响.此外温度的提高、摩擦的降低均有利于降低压制力,提高压坯密度均匀性,改善压坯应力集中现象.

Finite Element Simulation of Influence of Different Compacting Processes on Powder Metallurgic Products Properties

The metal powder compaction process is simulated with the finite element analysis software MSC/MARC. The simulation applies thermal mechanically coupled analysis based on the updated Lagrangian method to study the influencing rules of different compacting processes (temperature, friction, compacting style, etc). The mechanical characters (compacting force, ejecting force, stress distribution, etc) of the compaction process are also analyzed. The results indicate that friction condition is the crucial factor which influences the value and distribution of green density, double compaction can improve the distribution and values of green density which is made uneven and large deviation by means of single compaction. Increasing temperature is propitious to improve the plastic deformable capacity of powder particles, but the effect is not evident. Otherwise, the compaction temperature influences the properties of lubricant which influences the condition of friction so that the temperature should be considered when the compaction process is made. Increasing temperature and decreasing friction are propitious to decrease compaction pressure, improve the distribution of density, and also improve the phenomenon of stress concentration.