改变摩擦方式的挤压成形研究现状

Research status on extrusion with changing friction mode

挤压成形时坯料和模具之间的摩擦力使得成形载荷显著增加,严重影响模具寿命和工件质量。因此,改善摩擦条件、使之对成形的不利影响降低就成为目前挤压成形研究的关键之一。对静液挤压、挤压筒的有效摩擦、振动辅助挤压成形、往复旋转辅助挤压成形以及变滑动摩擦为滚动摩擦等几种改变摩擦方式的挤压成形进行了分析,结果表明:流体润滑、界面摩擦因子降低、摩擦矢量改变方向以及滚动摩擦代替滑动摩擦都能有效地降低摩擦对挤压成形的不利影响。

The friction between die and billet in extrusion will increase the forming load significantly, which results in poor precision and low die life. Therefore, it is critical to reduce friction and negative influences on metal forming. The approaches to realize extrusion by changing friction types were analyzed including hydrostatic extrusion, active friction of extrusion cylinder, vibration assisted extrusion, cy- clic torsional assisted extrusion and changing slide friction to roll friction. The results show that fluid lubrication, reducing interface fric- tion factor, changing friction vector direction and rolling friction can effectively reduce the negative influences on extrusion.