非牛顿特性下冷挤压流体动力润滑模型的建立

应用磨擦学和金属塑性成形理论，对冷挤压工艺中的流体动力润滑机理进行了分析。针对冷挤压高压、大剪应变率工况下，润滑剂呈非牛顿特性的特点，运用Ostwald非牛顿体模型，分别建立了冷挤压非稳定流体动力润滑状态和稳定流体动力润滑状态的数学模型，并运用该模型对以蓖麻油作润滑剂的纯铝冷挤压进行了分析。计算结果揭示了冷挤压过程中，润滑油膜厚度及油膜压力的分布。

Model of Hydrodynamic Lubrication under Non-Newtonian Feature of Lubricant During the Process of Cold Extrusion

The mechanism of hydrodynamic lubrication during the process of cold extrusion was analyzed by means of the theory of tribology and metal forming. In the light of the non-Newtonian feature of lubricant under the condition of high pressure and large shearing strain ratio during the cold extrusion, the mathematic models of unsteady and steady hydrodynamic lubrication states in cold extrusion were established respectively by Ostwald non-Newtonian model. Using this model, the cold extrusion of pure aluminum was analyzed, which uses castor oil as lubricant. The distribution of lubricant film thickness and stress during the cold extrusion was unveiled from the calculated result.