IMPACT EXTRUSION METHOD, TOOLING AND PRODUCT

摘要

A hollow preform impact extruded from a metal billet to produce a progressing wall at a transition wall thickness. An axially forward portion of the progressing wall is ironed by extrusion past an extrusion point to form a sidewall portion of a lesser thickness. Extruding is stopped while some of the billet remains to form the closed bottom end. The preform has a bottom portion, a sidewall portion and a transition wall portion extending between the bottom portion and the sidewall portion. The transition wall portion is thicker than the sidewall portion and can be formed into at least part of the rim of an expansion shaped container. An impact extrusion punch has a central axis, an axially forward, impact surface for impacting metal to be extruded, a transition region for directing material displaced by the impact surface and a rear extrusion point for ironing material extruded past the transition region.

主权项

1. An expandable metal preform for an expansion shaped metal container having a closed bottom, a rim and a sidewall, the preform comprising,
a closed end; and a tubular wall extending from the closed end and defining a longitudinal axis of the preform; the closed end including a bottom forming portion with a bottom wall thickness and the tubular wall including a sidewall forming portion with a sidewall thickness; the preform further including a rim forming portion intermediate the bottom forming portion and the sidewall forming portion, the rim forming portion including a transition wall adjacent the bottom forming portion and having a transition wall thickness larger than the sidewall thickness.