零件近净成形新工艺——差温无模锻造的热力耦合有限元模拟分析

Simulating analysis on thermal differential mouldless forging ——a new near net forming process by using coupled thermal-viscoplastic FEM

以AISI10 4 5钢圆柱体在环形加热源局部加热下的差温无模锻造为例 ,利用热力耦合有限元方法模拟其成形过程。模拟结果表明 ,差温无模锻造作为零件近净成形的一种新工艺是可行的。差温无模锻造成形的关键是要获得和控制金属坯料内部适宜的不均匀分布温度场 ,加热环和冷却环的适当组合可以获得成形所需的温度分布花样。在快速变形方式下 ,变形前的温度分布花样基本上决定了金属的流动模式 ,变形过程的持续加热对其影响甚微 ;在慢速变形方式下 ,变形过程的持续加热对金属的流动模式产生一定的影响。

The thermal differential mouldless forging of the AISI 1045 steel cylindrical rod subjected to ring heat sources, as an example, is simulated by using coupled thermal-viscoplastic FEM. The results reveal that it is feasible to use the thermal differential mouldless forging as a new near net forming process. Obtaining and controlling appropriate nonhomogeneous temperature distributions within metal billet is key for this forming process. The suitable combination of the heating and cooling rings can produce such temperature distributions. The metal flow mode is basically determined by temperature distributions prior to deformation under fast deformation operation and is affected very slightly by continuously in-situ heating during deformation. But the metal flow mode is affected by both the temperature distributions prior to deformation and the continuously in-situ heating during deformation under slow deformation operation.