| 摘要 |
936,583. Extruding. REYNOLDS METALS CO. April 19, 1960 [April 27, 1959], No. 13672/60. Class 83 (4). In the extrusion of metal tubes of varying diameters, a mandrel 100 is used comprising two portions 104, 112 of larger cross-section arranged alternately with two portions 108, 116 of smaller cross-section. A heated aluminium billet 12 is extruded by a ram 16 between a die 14 and the mandrel 100 to form a tube with internal and/or external thickened portions 126. The die bore and the cross-section of the mandrel may be circular, oval, square hexagonal, octagonal or triangular. The ram and mandrel may be integral or movable relatively to each other. A terminal end 120 of the mandrel determines the inside diameter of the forward end portion of the tube; the rear end of the tube is thickened externally only. The transition portions 114, 118 of the mandrel may be tapered or curved convexly or concavely, Fig. 9 (not shown). Other embodiments are described for forming tubes with two or more external thickenings. These tubes may be given a slight overall internal taper by using a mandrel with a slight overall taper.
|
