热挤压模磨损规律及磨损对模具寿命的影响

采用Archard磨损模型模拟分析了模具硬度、初始温度、润滑条件在一次成形后对模具磨损的影响规律。结果表明：模具初始硬度越高,模具抗磨损能力越强;当摩擦因子m〉0.35时,模具的磨损量迅速增大;温度对磨损的影响较为复杂,一方面温度使模具表层发生软化,加速磨损,另一方面温度又使模具表面形成氧化膜,阻止金属表面的大面积接触,磨损量反而减小。最后将温度引入Archard磨损模型中,提出了用磨损量来预测模具使用寿命的新方法。

Wear Rule and Effects on the Die Service Life during Hot Extrusion

The rules of the wear were analyzed by using the Archard wear model at different original hardness and original temperature of the punch and different frictional coefficients during one extrusion. It shows that the higher of hardness of the punch the better resists wear, and that the wear of the die increase rapidly when the frictional coefficient exceeds 0.3, and that the effect of temperature on the wear is complex. On one hand, it increases the wear by making the surface layer of the die soften; on the other hand it decreases the wear by forming oxidation film on the face of the die. At last, the estimation method of die service lifetime by wear during hot extrusion processes was put forward by importing the temperature into the Archard wear model.