Power-energy conditions of round item hydro-mechanical pressing

Abstract

One of the main widespread methods of metal forming is pressing characterized by a favorable plastic deformation pattern with the predominant effect of all-round compressive stresses. This allows deforming low-ductile materials and alloys with sufficiently high degrees of deformation. This paper studies plastic deformation conditions at hydro-mechanical pressing as one of pressing types. A distinctive feature of hydro-mechanical pressing as compared to other pressing types is the ability to control the movement of the billet and prevent its ejection at the final process stage. The study covers the conditions of hydro-mechanical pressing which combines the use of high-pressure working fluid and the mechanical impact of the tooling on the pressing die. Formulas for the components of the total hydro-mechanical pressing stress are derived to serve the basis for determination of the optimal process tool geometry. Taper angles of the hydro-mechanical pressing die are optimized depending on the main pressing process parameters. The dependency graphs are plotted for the ratio of pressing stress to the resistance of pressed material deformation as a result of drawing that confirmed the presence of optimum taper angles of pressing dies.