Analysis of Shaped Bars with Various Curvatures UsingExtrusion Process through Inclined Die

Abstract

The mechanisms responsible for the formation of rectangular and trapezoidal bars by an extrusion process in which dies are inclined at various angles were investigated using numerical simulations. The greater the die inclination angle or the aperture exit angle, the smaller the radius of curvature of the extruded bar. The calculated radius of curvature agreed well with the radius observed in experiments. The particle flow pattern, one of the outputs of the simulation, was used as a basis for investigating the mechanisms of curvature generation. When the die inclination angle was increased in the case of the extrusion of rectangular bars, the volume of dead metal increased, causing material flow in the plane perpendicular to the extrusion direction. This material flow gave rise to curvature of the extruded bar. It was also found that when the cross section was trapezoidal, the asymmetry of the container aperture caused differences in material flow velocity between the top and bottom portions; these differences affected the curvature.

Effects of Die Dimensions for Curvature Extrusion of Curved Rectangular Bars

“…6,7) However, because the extrusion ratio is the ratio of areas, the effects of the aperture height ratio and the aperture width ratio are not necessarily equivalent. It is therefore necessary that each be evaluated independently and that the die thickness effect also be examined, for detail investigation of the die dimension effects.…”