Improvement of machining yield and life of hemispherical core die for hollow extruded shape of 6063 aluminum alloy by casting core material

Abstract

The present work is on the development of casting core of extrusion die for a hollow shape of 6063 aluminum alloy. The static stress distribution of a hemispherical core during extrusion was analyzed by finite element method. The adoption of hemispherical core is found to be effective in the reduction of die weight and in the moderation of peak tensile stress on the core, which in turn improves the life of die, in comparison to a conventional port-hole die. The cooling arrangement for unidirectional solidification of near-net shape cast block was determined through a solidification simulation, which could attain the mechanical properties necessary for cast materials. By machining a hemispherical core die from the near-net shape cast block, the machining time is shortened by 50%, the machining yield increases 2.6 times and the amount of raw material is reduced by 38% in comparison to a hemispherical core die made from a forged ingot. The displacement during extrusion of the shape of the cast core is less than that of a hemispherical core made from a forged ingot.