B21J1/00—Preparing metal stock or similar ancillary operations prior, during or post forging, e.g. heating or cooling
B21J1/02—Preliminary treatment of metal stock without particular shaping, e.g. salvaging segregated zones, forging or pressing in the rough
B—PERFORMING OPERATIONS; TRANSPORTING
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
B21C23/001—Extruding metal; Impact extrusion to improve the material properties, e.g. lateral extrusion
Procédé de fabrication d'une pièce creuse en un matériau métallique et utilisation de ce procédé pour fabriquer une tige ou un balancier de train d'atterrissage