Continuous extrusion of metals

Apparatus for effecting continuous extrusion of metal from a feedstock in particulate or comminuted form, which apparatus includes:

• (a) a rotatable wheel member arranged for rotation when in operation by a driving means, said wheel member has formed peripherally thereon a continuous circumferential groove;
• (b) a cooperating shoe member which extends circumferentially around a substantial part of the periphery of said wheel member and which has a portion which projects in a radial direction partly into said groove with small working clearance from the side walls of said groove, said shoe member portion defining with the walls of said groove an enclosed passageway extending circumferentially of said wheel member;
• (c) feedstock inlet means disposed at an inlet end of said passageway for enabling feedstock in loose particulate or comminuted form to enter said passageway at said inlet end whereby to be engaged and carried frictionally by said wheel member, when rotating, towards the opposite, outlet end of said passageway;
• (d) an abutment member carried on said shoe member and projecting into said passageway at said outlet end thereof so as to substantially close said passageway at that end and thereby impede the passage of feedstock frictionally carried in said groove by said wheel member, thus creating an extrusion pressure in said passageway at said outlet end thereof;
• (e) a die member carried on said shoe member and having a die orifice opening from said passageway at said outlet end thereof, through which orifice feedstock carried in said groove and frictionally compressed by rotation of said wheel member, when driven, is compressed and extruded in continuous form, to exit from said shoe member via an outlet aperture;
• and
• (f) cooling means disposed downstream from said abutment member and adapted to cool adjoining parts of said abutment, shoe and wheel members at a location disposed immediately downstream of said abutment member, and to extract from said parts heat generated upstream of said abutment member in said passageway;
• said passageway comprising a primary zone extending downstream from said inlet end of said passageway, in which primary zone said particulate or comminuted feedstock is compacted, by rotation of said wheel member, to progressively eliminate voids in the advancing feedstock and so form an agglomerated mass of feedstock metal, and an adjoining, substantially shorter, secondary zone disposed downstream of said primary zone and extending at least to said die orifice, in which secondary zone said mass of metal is progressively compressed, by rotation by said wheel member, to a desired extrusion pressure sufficient to extrude said mass of metal through said die orifice, the radial depth of said passageway being substantially unchanging in said primary zone, and decreasing gradually in said secondary zone in the direction of rotation of said wheel member at a relatively high rate and in a manner such as to produce in that zone adjacent the die orifice a metal flow pattern more closely resembling that which is achievable with feedstock in solid form.