Continuous hydrostatic extrusion process and apparatus
AssigneeTrefimetaux
InventorMarc Moreau
Life of this patent
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Abstract
The invention concerns a process and apparatus for continuous hydrostatic extrusion wherein the pressure of the hydrostatic fluid is used to apply the blank to be extruded firmly against the walls or the bottom of a groove provided in a rotor, in such a way that the blank is entrained by the rotor without slipping to an extrusion chamber from which the blank is spontaneously extruded through a die. The invention finds use in particular for continuous extrusion of metal and alloys, including those which have a low degree of ductility.
Claims10
Apparatus for continuous hydrostatic extrusion of a first object, referred to as a blank, of indefinite length, into the form of a second object, which is also of indefinite length but of different section;
- the apparatus comprising two co-operating coaxial members, one being a movable member, referred to as a rotor, and carrying at its surface a groove of revolution, defined by a pair of opposed side walls and a bottom, which is adapted to receive the blank to be extruded in contact with at least two of said walls and bottom to define separate outward and inward zones respectively above and below the points of contact with said two of said walls and bottom, the other member being fixed, referred to as a stator, and forming, over a first sector of the groove to contain the blank and a viscous fluid, a cover which is substantially sealed with respect to fluid, the stator also comprising, over a second sector of the groove disposed downstream of the first sector, a relief portion which totally blocks the section of the groove and which is precisely adapted thereto to seal the section of the groove relative to the viscous fluid, means for supplying solely the outward zone of the groove with viscous fluid under high pressure from a pressure generator which can be of known type, and an aperture disposed in the stator opposite the first sector of the groove, in the vicinity of the second sector, the aperture opening by way of an elongate conduit which passes through the stator, into an extrusion chamber which communicates with the exterior through at least one die orifice, the viscous fluid supply means producing in the first sector of the groove a pressure gradient from a point of entry for the blank, at ambient pressure, to the conduit which opens into the chamber in which the extrusion pressure exists.
A process for the continuous hydrostatic extrusion of a first object, referred to as a blank, of indefinite length, into the form of a second object which is also of indefinite length but different section, comprising the steps of introducing the blank, accompanied by a substantial amount of a viscous fluid, into a groove provided in a drive rotor wherein said blank defines two separate concentric zones, the first zone being on the outward side and being towards a stator which forms a cover applied to the rotor, said first zone directly receiving the viscous fluid under high pressure by an introduction means and generating a pressure which progressively increases from the entry point at ambient pressure, to a chamber in which the extrusion pressure is obtained, the pressure of the viscous fluid received in the first zone being generally higher than that obtained in the second zone, which is on the inward side at the bottom of the groove, this pressure difference applying to the blank a force which tends to press it into the groove and which produces a sufficient degree of grip for the movement of the rotor to entrain the blank without slipping, from the upstream region, at ambient pressure, in a downstream direction to the entry of a high-pressure chamber from which the blank issues by extrusion through at least one die orifice.
Dependencies are inferred from the claim text.