CPC C21D 9/40 (2013.01) [C21D 1/18 (2013.01); C21D 1/42 (2013.01); C21D 9/0062 (2013.01); F16D 3/2055 (2013.01)] | 9 Claims |
1. A method for manufacturing a trunnion for a constant velocity joint, the trunnion having a plurality of journal units provided on the outside thereof around a hub unit, the method comprising:
a first step of manufacturing the trunnion;
a second step of thermally treating a rounded outer circumferential surface of the journal unit; and
a third step of thermally treating a connection unit disposed between the journal unit and the hub unit and having a diameter smaller than that of the journal unit,
wherein the second step or the third step further includes
a heating step, through a high-frequency induction heating device, of carrying out heating for 1.5 to 2.8 seconds with an output from 64 to 68 kilowatts (KW),
a delaying step of having a time difference from 0.05 to 0.15 seconds, and
a cooling step of carrying out cooling for 4.5 to 5.5 seconds, and
wherein, in the second step or the third step, an input current is from 150 to 159 amperes (A), a positive voltage is from 5.6 to 6.2 kilovolts (KV), and a positive current is from 4.5 to 5.0 A.
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