Method of hydrostatic extrusion for holding a billet during insertion into a pressure chamber

摘要

A holding force for retaining a billet and die against a die support is obtained by forming a pressure drop in the pressure medium flow in a gap between the billet and a surrounding constructional element inside the pressure chamber. The gap may be formed by the outer surface of the billet and the inner surface of the high pressure chamber. The gap may also be formed between the outer surface of the billet and the inner surface of a spacing tube mounted within the pressure chamber. The spacing tube is constructed with a portion having a smaller diameter than the remainder of the spacing tube to provide a gap to achieve a sufficient pressure drop for retaining the billet and die against the die support.