Metal extrusion
AssigneeAlcan International Limited
InventorsMartin R. Jarrett, William Dixon
Life of this patent
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Abstract
A billet of extrudable metal, particularly an Al alloy is tapered at its back end. The billet is compressed longitudinally so that the metal of the tapered end is upset transversely. The compressed billet is hot extruded. The upsetting improves the fracture toughness of the back end of the extrusion. This is useful in long extrusions for the aircraft industry.
Claims13
A method of producing an extrusion, which method comprises providing a billet of extrudable metal said billet having an untapered part towards its front end and a back end which has a reduced cross section along at least part of its length, the cross-sectional area of the billet at the back end being up to 90% of the cross-sectional area of the untapered part of billet, compressing the billet along its length such that the metal of the back end of the billet is upset in a transverse direction, and extruding the compressed billet.
Dependencies are inferred from the claim text.