| 摘要 |
PURPOSE: To provide a cold forging process capable of improving operating ratio of forging press by solving a problem of crack formation on product and reducing product manufacturing process. CONSTITUTION: The cold forging process comprises a step of cutting a work; a normalizing step of air cooling the heated work after heating the cut work to 850 deg.C and maintaining a heating temperature to 850 deg.C for a first set time; a spheroidizing step of air cooling the work at 640 deg.C through slow cooling(furnace cooling) while maintaining the work at a set temperature for a set time per respective steps after heating the normalized work to 730 deg.C and maintaining a heating temperature to 730 deg.C for a second set time; a step of shot blasting the spheroidizing completed work; a step of pretreating(lubricating) the shot blasting completed work; and a step of cold forging the pretreatment completed work by composite forming consisting of forward extrusion, up setting and backward extrusion.
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