Method and mold for cold extrusion forming of wheel hub

A method for forming a wheel hub through cold extrusion, the method comprising:

• S1:
• placing a round cake of forgeable metal material into a first die set, and extruding, via a cold extrusion process by the first die set, the round cake of forgeable metal material to form a cylindrical blank which is U-shaped and comprises an opening facing downward, wherein an upper portion of the cylindrical blank forms a spoke and a lower portion of the cylindrical blank forms a rim, and a diameter of a flange of the cylindrical blank is greater than a diameter of the rim of the cylindrical blank, and removing the cylindrical blank from the first die set;
• S2:
• placing the cylindrical blank into a second die set, and extruding, via a cold extrusion process by the second die set, the cylindrical blank to obtain a secondary blank having a desired spoke shape, forming spoke recesses by extrusion on both upper and lower sides of a center of the spoke of the secondary blank, forming an extruded step on an outer wall of the flange of the secondary blank, and removing the secondary blank from the second die set;
• and
• S3:
• inverting the secondary blank 180 degrees and placing into a third die set, preliminarily forming, via a cold extrusion process by the third die set, the rim of the secondary blank to cause the rim to assume a flared shape, and then cold extruding and bending outward a top end of the rim, thereby obtaining a finished wheel hub.