加圧雰囲気下における高Cr含有鋼の窒素吸放出速度と窒素溶解度

抄録

Nitrogen solubility and rate of nitrogen absorption and desorption in High Cr Steel under Pressurized Atmosphere were investigated using pressurized directional solidification furnace. In this study, melting experiments were performed under maximum 1.0 MPa gas condition. It was found that nitrogen solubility was deviated from Sieverts'Law over 0.60 mass% nitrogen contents in molten high Cr steel. It was assumed that this phenomenon was not caused by high nitrogen partial pressure but by high nitrogen content in molten high Cr steel. In this study, 1st and 2nd order nitrogen interaction parameters were estimated. And calculated results using estimated parameters were suitable to explain nitrogen solubility of molten high Cr steel. Nitrogen absorption rate was almost same in same nitrogen partial pressure even if total pressure was different. In this study, the apparent mass transfer coefficient in liquid phase of high Cr steel at 1823K was estimated approximately 8.8×10⁻⁵ (m·s⁻¹). Nitrogen desorption rate was decreased with increase in total pressure or nitrogen partial pressure. It was indicated that mixed control model of gas phase mass transfer and chemical reaction at gas/liquid interface could be applied to explain nitrogen desorption reaction of molten high Cr steel under pressurized atmosphere.