B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES, PROFILES OR LIKE SEMI-MANUFACTURED PRODUCTS OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
B21C23/00—Extruding metal; Impact extrusion
B21C23/02—Making uncoated products
B21C23/03—Making uncoated products by both direct and backward extrusion
B—PERFORMING OPERATIONS; TRANSPORTING
B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
B21D51/00—Making hollow objects
B21D51/16—Making hollow objects characterised by the use of the objects
B21D51/36—Making hollow objects characterised by the use of the objects collapsible or like thin-walled tubes, e.g. for toothpaste
Procédé de refoulage pour le corroyage d'un lopin métallique, procédé de préparation d'un lopin à une opération de forgeage selon le procédé et dispositif de mise en oeuvre du procédé