Extrusion press pressure plate allowing complete venting of entrapped air - has convex curvature at front face of plate and passage(s) in (expansion) wear ring

摘要

Vented rigid pressure plate has a dia. smaller than that of an adaptor or the ram to which it is attached and can travel with play in the extrusion container. Wear ring, made of the same material as the pressure plate, is fitted between the pressure plate and the adaptor or the ram and has a thickened outer edge region which is flush with the front face of the pressure plate and which thickens in the outward direction at an obtuse angle. Venting is obtd. by provision of a convex curvature (2) at the front face of the pressure plate (1) and passage(s) (4) in the (expansion) wear ring (7). Passages (4) are pref. located in the wear ring (7) where the sides of the acute angle (13) of the thickened portion (9) intersect. Wear ring (7) pref. has an overlap region (5) which overlaps the adaptor (3) or the ram. ADVANTAGE - Design provides complete venting of air trapped between the billet, the container and the pressure plate.