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
B21C37/00—Manufacture of metal sheets, rods, wire, tubes, profiles or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
B21C37/06—Manufacture of metal sheets, rods, wire, tubes, profiles or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes
B21C37/15—Making tubes of special shape; Making tube fittings
B21C37/28—Making tube fittings for connecting pipes, e.g. U-pieces
Corps de chauffe pour radiateur electrique comportant un filament metallique a enroulement helicoidal a zones de spires differenciees et procede de realisation dudit enroulement
Procede de preparation d'un element longiligne en forme d'helice, en resine synthetique pour sa fixation dans un corps tubulaire, par liberation de tensions internes induites