| 摘要 |
PURPOSE:To reduce dimensional errors due to the sagging of the tips of teeth when carburized and hardened toothed parts such as gears are produced, by subjecting the tips of the teeth to carburization preventing treatment such as copper plating before carburization followed by hardening and tempering. CONSTITUTION:A case hardening Cr steel as stock is forged into a blank, this blank is turned to a prescribed outside diameter and a carburization preventing layer 3 is formed on the peripheral surface by copper plating. Toothing and shaving are then carried out to form a cylindrical helical gear 1. The gear 1 having copper plating 3 for preventing carburization on the tips 2 of the teeth is gas-carburized at 900-850 deg.C, oil-hardened and tempered at 180 deg.C. The tips of the teeth do not sag and gears having superior accuracy in the tooth profile can be produced in a high yield.
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