Importance of tribological conditions at multi-phase ironing

Abstract

The importance of tribological conditions in metal forming is well known and equal to other forming process factors – material, machine and tool. The results obtained in investigation of the effects of tribological conditions in cold metal forming are presented in the paper. A typical tribo-model is strip ironed between angled die surfaces. The changes in pressure, friction coefficient and surface topography in single and multi-phase sliding in the conditions of boundary lubrication were investigated. The low carbon mild steel sheet, suitable for plastic forming, was used. In dependence on conditions in contact, it is possible to realize various friction lows. In course of investigation the so called constant low friction has been realized in condition of high contact pressures. The results of multi-phase sliding, which simulates the moving of piece through dies, are especially significant.