Influence of nitriding modes and ammonia on nitrogen content of oriented silicon steel

The effects of ammonia proportion and the nitriding modes of spraying as well as non-spraying on nitrogen content in oriented silicon steel were studied.The change of oxidation film before and after nitriding is analyzed.The results show that the nitriding which is proceeded in the steel with the oxide film of 0.1μm at 750 ℃,1%～5%(volume percentage) NH3 has no prominent nitriding effect in a short time.However,the nitriding effect is prominent when volume percentage of NH3 is 10%～40%.With increasing the volume percentage of NH3,the nitrogen content increases.When the volume percentage of NH3 is 30%,nitrogen content by spraying nitriding mode is 2.5 times as much as that by non-spraying.Hydrogen in the nitriding atmosphere can deoxide the thickness of the oxidation film by 20%.