Method and device for surface hardening

Abstract

Abstract PURPOSE:To enable pollution-free surface treatment with easy assurance of quality by heating up a work to a prescribed temp. in a nonoxidative state and subjecting the surface thereof to a soft nitriding treatment and then to an oxidation treatment. CONSTITUTION:The work 8 is disposed in a heat treatment furnace 7 and is heated up in the nonoxidative state by the gaseous nitrogen supplied from a gas supply pipe 11. Gaseous ammonia is supplied by opening a solenoid valve 12 of a gaseous ammonia supply pipe 13 to start the soft nitriding treatment when the work 8 attains the prescribed temp. The solenoid valve 12 is closed after the soft nitriding treatment. A burner 16 is ignited and the combustion is continued in a combustion chamber 17. The waste combustion gas thereof is supplied into the heat treatment furnace 7 to oxidize the soft-nitrided surface of the work 8 and to form fine Fe3O4 having excellent resistance to wear and corrosion thereon. The work 8 is then lowered into a hardening oil tank 4 and is hardened. The film having excellent fatigue resistance strength, sliding characteristic, etc., is thereby easily formed.

Inventors

• 👤 Katsuyuki Matsui

Bibliographic Details