【摘要】 玻璃润滑热挤压工艺是生产大口径厚壁无缝钢管的重要方法,然而对玻璃润滑热挤压润滑行为的理论分析仍然非常欠缺。将玻璃润滑行为分为两个阶段,熔融玻璃的形成阶段和玻璃润滑膜在定径带上的演化阶段,得到玻璃垫内的温度、玻璃粘度、玻璃流动速度沿玻璃垫厚度方向的分布,分析熔融玻璃的流量和玻璃润滑膜的厚度,得到两种速度边界条件下预测挤压制品表面覆盖的玻璃润滑膜厚度的理论模型,并得到判定玻璃润滑工艺是否稳定的稳定性判据,从理论上验证大口径厚壁无缝钢管在70 mm/s速度下实现稳定润滑工艺的可行性。提出采用数值模拟预测坯料表面温度随挤压过程的变化,并结合理论模型预测玻璃润滑膜厚度的方法,与试验结果对比,证明该模型具有较好的预测精度。更多还原

【Abstract】 Glass lubricated hot extrusion process is a very important way to manufacture large-diameter,thick-walled seamless steel tubes.However,theoretical study on its lubrication behavior is still inadequate.The lubrication process is divided into two stages,the formation of the melted glass and the evolution of the film during the calibration phase.The temperature distribution,viscosity distribution and the velocity distribution throughout the lubrication pad is obtained.The glass flow rate based on two velocity boundary conditions and the stability parameter are obtained.The feasibility to extrude large steel tubes at 70 mm/s is verified theoretically.The way to predict the glass film thickness throughout the extruded product combining a FEM model to calculate the surface temperature of the billet and a theoretical model is proposed.The predicted glass film thicknesses are in good agreement with experimentally observed results.更多还原