复杂锻件净成形过程中模具回火现象的数值模拟研究

Numerical analysis of temperature field and temper of net-shape forming dies during cyclic forming processes

以数值模拟方法为工具 ,以齿轮的温态净成形 (Net ShapeForming)工艺为对象 ,研究了复杂锻件净成形过程中热力学因素与模具材料性能的关系 ,重点研究了模具在循环热交换条件下的模具瞬态温度场及由此产生的回火现象。模具温度场连续变化的数据用于H13材料的回火模型 ,获得了连续锻打后的模具硬度 ;测定了生产中已失效模具的硬度分布 ,模拟计算值与实测值吻合较好 ,证明了分析模型和算法的正确性。分析结果为模具寿命预测和工艺优化提供了依据。

The cyclic varied temperature field of net-shape forming dies during continuous processes is analyzed by numerical simulation method. The research is focused on temper phenomenon of dies caused by the heat transfer from hot workpiece to die and the die cooling processes in environment. Based on the analysis results, the relationship between thermodynamical factors and variation of die material property is proposed. In turn, the calculation of hardness decrement during the die life cycle is conducted according to temper theory. The hardness values of a failed die for precision forming of bevel gears in workshop are measured. The comparison between calculated hardness values and measured ones shows good agreement, and gives verification of the analysis model and algorithm.