To provide a nitriding-quenching method, a heater for nitriding-quenching and a nitriding-quenching apparatus by means of which discomposed quantity of ammonia gas on the surface of the heater is made constant and residual ammonia concentration in a furnace is stabilized, thereby the quality of the nitriding-quenched parts can be improved.
The nitriding-quenching method is provided in which a workpiece 11 constituted of an iron or an iron alloy is set in a heat treating furnace 1 supplied with ammonia, and the inside of the heat treating furnace 1 is heated with the heater 13 which is constituted of a metallic member and disposed in contact with the atmosphere in the heat treating furnace 1, whereby nitrogen is penetrated and diffused into the workpiece 11 and also the quenching is performed. In the method, the degree of decomposition of the ammonia on the surface of the heater 13 is controlled by adjusting the forming range of an oxide film on the surface of the heater 13.
MITSUHAYASHI MASAHIKO
YAMAMOTO IZURU
TAWA HISAYOSHI
KABASAWA HITOSHI
NIPPON TECHNO KK
| JPS63303132A | 1988-12-09 | |||
| JPH0827515A | 1996-01-30 | |||
| JPH08260059A | 1996-10-08 | |||
| JP2007046088A | 2007-02-22 |
Next Patent: TITANIUM ALLOY BILLET HAVING EXCELLENT DEFECT DETECTABILITY IN ULTRASONIC CRACK INSPECTION TEST