To provide a nitriding treatment method which reduces variations of hardness on the surface of a steel material and surely imparts it desired hardness, and to provide a nitriding treatment apparatus.
The nitriding treatment method includes: introducing a gas containing ammonia and oxygen into the nitriding treatment apparatus 6; heating the gas to a predetermined temperature range; measuring oxygen concentration in the nitriding treatment apparatus 6; and adjusting the oxygen concentration in the nitriding treatment apparatus 6 on the basis of the measured oxygen concentration. The adjusting method includes: previously setting a concentration range of necessary oxygen on the basis of relationship between the hardness on the surface of the steel material and the oxygen concentration; decreasing the amount of oxygen to be introduced into the nitriding treatment apparatus 6, when the measured oxygen concentration is higher than the set range; and increasing the amount of oxygen, when being lower. The nitriding treatment apparatus includes: a heating means for heating the inside of three nitriding treatment apparatus; an ammonia-gas-introducing means 22; an oxygen-gas-introducing means 23a; an oxygen-concentration-detecting means 35a for detecting the concentration of oxygen in the nitriding treatment apparatus 6; and an oxygen-concentration-adjusting means for adjusting the concentration of oxygen in the nitriding treatment apparatus 6, on the basis of the oxygen concentration detected by te oxygen concentration-detecting means 35a.
NARITA NAOKI
SARUYAMA MASAOMI
TAKAGAKI MASASHI
YAMAGUCHI KAZUYOSHI
SUMITA TERUHIKO
KOYO THERMO SYS KK
| JPS62270761A | 1987-11-25 | |||
| JPS60251265A | 1985-12-11 |
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