METHOD FOR EXTRUDING SHORT-LENGTH TUBES Russian patent published in 2003 - IPC

FIELD: plastic metal working, namely production of short-length tubes of hard- to-form metals and alloys. SUBSTANCE: method comprises steps of placing in die holder centering ring whose inner diameter corresponds to that of molding needle at providing sliding fit; feeding heated blank with axial opening to container; extruding tube in gap between pressure pad and wall of container by one or several transitions for forming bottom and for separating bottom through cut-off ring; heating technological washer with axial opening; placing said washer between centering ring and blank in container when diameter of axial opening of heated technological washer corresponds to diameter of molding needle at providing sliding fit; extruding tube until forming bottom in technological washer. Before extrusion process needle is joined to ram with possibility of radial motion; pressure pad may freely move on needle. EFFECT: enhanced factor of metal usage due to lowered wall thickness difference of extruded tubes, due to extruding tube without forming bottom of tube material, reduced crops, normalized properties of extruded metal along the whole length of tube. 3 cl, 4 dwg