Production of ductile metal wheels

摘要

1,057,066. Making wheels; extruding; forging; stamping. REYNOLDS METALS CO. Oct. 16, 1963 [Oct. 24, 1962], No. 40919/63. Addition to 971,259. Headings B3A, B3H, B3P and B3Q. [Also in Division B7l A ductile metal wheel, particularly for a vehicle, is made by compressing a workpiece between punches 248, 264, Fig. 8, and extruding the flowing metal through an annular gap to form the cylindrical wall. In the manufacture of an integral vehicle wheel from magnesium, copper or preferably aluminium or its alloys, Fig. 1, a continuous cast billet 20 is sawn into discs 24 which are grit blasted, heated at 26, upset at 30 between dies, Fig. 3 (not shown), to form blanks 32 from which the flash 42 is sheared by an annular die, Fig. 4 (not shown). The resulting blank 34 is then heated at 54, simultaneously backwardly and forwardly extruded at 60 and the ends trimmed at 68. After further heating at 86 the blank 70 is deformed at 90 to wheel rim shape between co-operating dies, further heated and deformed at 100, 102 respectively and quenched, preferably in boiling water, at 112. The second deformation step may be omitted. Various finishing operations such as punching the bolt, valve and hub receiving holes 104, 111, 106, Fig. 7, are followed by etching, polishing, burnishing, anodizing and painting the finished wheel 303. Alternative forms of wheels for receiving solid tyres are described, Figs. 20, 22 (not shown), and references are made to the manufacture of pulley and gear wheels. Specific examples are given, including the temperatures used, for the manufacture of wheels from various aluminium alloys and the results of comparative rolling and fatigue tests against conventional steel wheels. Lubricating.-During the upsetting, extruding and deforming operations the workpiece is lubricated with colloidal graphite. Extruding.-The upset and trimmed blank 56 located by a centering boss 34 is extruded between a stationary lower punch 248, Fig. 8, a reciprocable upper punch 264, and a surrounding annular die 218 having a slightly conical downwardly converging surface 242. The die 218 is biased downwardly against a ring 206 by springs 231. Both punches have enlarged diameter noses 276, 278, Fig. 15 (not shown), to reduce frictional drag of the flowing metal, and longitudinal grooves 292, 294, Fig. 11 (not shown) for forming internal ribs 288, 290 in the workpiece 62, Fig. 1. Electric heaters 258, 274 are provided for the punches. After extrusion the upper punch 264 is raised, Fig. 16 (not shown) whilst the workpiece is held between the lower punch and die 218 by the pinch effect of the conical surface 242. Then the die 218 is raised by compressed air admitted through ducts 220, 222, 224, and assisted by a hydraulically-operated knock-out rod 260 whose head 262 engages the centring boss 34, to lift the workpiece from the lower punch 248, Fig. 17 (not shown). Finally the workpiece is ejected from the die when latter is lowered subsequently into the extrusion position. Stamping.-After trimming the ends and further heating, the workpiece is deformed between upper and lower dies 320, 322, Fig. 12 (not shown), whilst enclosed by three die segments such as 330, 332, pressed inwardly by an inclined surface 344 on cam ring 346 secured to a cam-operated vertically movable platen 347 carrying the upper die 320. The segments slide transversely on a spring-loaded pad 336 and are held in their closed position by member 374. When the platen 347 is raised the die segments 330, 332 are withdrawn by inclined surfaces 380 co-operating with surfaces 382 on outer members 383 secured to the die segments by bolts 3831. All the dies are heated by electric heaters such as 388 and a stripper plunger 386 is provided. After further heating to a solution heat treating temperature, a further deformation step is performed in similar dies, Fig. 13 (not shown), but having four die segments.