鉄鋼のガス浸硫窒化法

抄録

The authors investigated the effects of ammonia concentration on gas nitrosulfidizing of iron and steel at 570°C for 120min. in the atmosphere of mixed gases composed of a carrier gas, H₂S, and NH3. The amount of nitrosulfidizing (weight increase during this treatment) was lager with the increase of ammonia concentration. The hardness of cross-section obtained at 30-50% of NH₃ concentration was similar to that obtained by nitriding treatment. It was confirmed by X-ray diffraction and EPMA that the surface layer obtained at 10% of NH₃ concentration was mainly composed of FeS; and it was composed of FeS, Fe_1-xS, FeN₃, Fe₄N, etc. when obtained at 30-50% of NH₃ concentration.