工具转速对AZ31B镁合金圆锥盒摩擦热渐进成形板料温度及成形能力的影响

Influence of tool speed on sheet temperature and formability of magnesium alloy AZ31B cone box in frictional heat incremental forming

针对镁合金室温下成形性能差的缺点,为了提高其成形性能,采用不需要外部加热而依靠自身摩擦热进行的镁合金摩擦热渐进成形进行研究,介绍了镁合金圆锥盒摩擦热渐进成形的基本原理、工艺路径设计以及成形过程分析。制定了2 mm厚AZ31B镁合金板料成形锥角45°和高度60 mm的圆锥盒形件的工艺方案,选择工具旋转速度为0~6000 r·min^(-1)、进给速度为1000~2000 mm·min^(-1),设计成形工具的运动轨迹之后进行渐进成形工艺实验。实验结果表明,成形高度和进给速度等因素对成形性能的影响较小,而工具转速对成形性能影响较大,转速越高(0~6000 r·min^(-1))则板料与工具摩擦产生的温度就越高。当转速在0~1000 r·min^(-1)或≧1500 r·min^(-1)时,成形不能进行,转速在1000 r·min-1≤ω≤1500 r·min^(-1)时,成形可以顺利进行。因此可以通过控制工具转速所产生的摩擦热有效提高板料的成形性能。

For the poor formability of magnesium alloys at room temperature,it was studied the frictional heat incremental forming method for magnesium allog sheets from self frictional heat instead of external heating to improve forming performance. The forming principle,process plans and forming process were introduced,and the process plan was designed that a circular conical cup magnesium alloy AZ31 B with 2 mm thickness was formed with 45° inclination angle and 60 mm height. Furthermore,the forming trajectory was designed,and then incremental forming experiments were done by choosing tool rotational speeds 0- 6000 r·min^（-1）and feed rates 1000- 2000 mm·min^（-1）.Experiment results show that forming height and feed rate have little effect on forming performance,and the tool rotation speed has great influence on the forming performance,thus,the faster the tool rotation speed is,the higher the temperature is. But the forming is failed when the tool rotation speed is 0- 1000 r·min^（-1）or ≧ 1500 r·min^（-1）,while the forming is successful at 1000 r·min^（-1）≤ω≤1500 r·min^（-1）. The forming performance is enhanced by frictional heat from tool rotation speed.