Manufacturing methods for wheel rim, spoke and steel wheel and steel wheel formed by methods

A method for manufacturing a wheel rim of a steel wheel, comprising:

• Step 1:
• heating a round tubular object in a heating furnace;
• Step 2:
• transferring the heated round tubular object onto a hot press, a temperature of the heated round tubular object transferred onto the hot press being higher than a required temperature, and the required temperature being at least 950° C.;
• Step 3:
• machining an internal contour of the round tubular object by use of a mold of the hot press to form the wheel rim;
• and
• Step 4:
• while keeping the wheel rim in the mold of the hot press, cooling the wheel rim by use of a water sprayer in the hot press, wherein the water sprayer comprises a nozzle array, and the nozzle array sprays water onto a tire mounting surface of the wheel rim in an overlapping and crossing manner, such that the wheel rim is cooled to about 200° C. and then extracted from the mold of the hot press, the extracted wheel rim then is tempered at 400° C., wherein tempering time is between 20-60 minutes.