| 摘要 |
PURPOSE: To provide a heat treatment method of gas nitriding capable of stably maintaining quality and productivity during mass production of steel products by controlling process conditions only without additional facility expansion when hardening the surface of the steel products by gas nitriding. CONSTITUTION: In a method for gas nitriding metal products, the heat treatment method of gas nitriding comprises first step of heat treating the metal products for a first set period of time in the state that a predetermined temperature is maintained; second step of heat treating the first heat treated metal products for a second set period of time at an increased temperature compared with the first step; and third step of discharging the second heat treated metal products in a temperature range of about 120 deg.C while slowly cooling the metal products, wherein the metal products are heat treated at about 510 deg.C for 30 hours in the first step, and wherein the metal products are heat treated at about 530 deg.C for 52 hours in the second step.
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