Abstract:In the process of steelmaking, it is difficult to control the nitrogen mass fraction of finished product below 0.003%. For the production of Al-killed steel, the general manufacture routine is BOF-RH-CC, and nitrogen absorption and desorption could happen in every process. In order to study the change of nitrogen content in the whole smelting process, nine industrial tests were carried out. The results show that the nitrogen content in steel at the steelmaking end-point increases with the increase of carbon and oxygen accumulation, which reflects the stirring effect of bottom blowing. During tapping, nitrogen absorption occurred, and the longer the alloying time is, the lower the carbon content at the steelmaking end-point is. The more the number of taps used, the greater the amount of nitrogen absorption increased. For the nitrogen desorption behavior during RH process, the newer the RH immersed nozzle is, the more nitrogen desorption occurs. According to the conclusion, the feasible measures to control the nitrogen content in steel are proposed.
贾毅, 刘春阳, 韩少伟, 王彦锋, 李春奇, 万力凝. 铝镇静钢氮含量控制分析[J]. 中国冶金, 2021, 31(3): 116-121.
JIA Yi, LIU Chun-yang, HAN Shao-wei, WANG Yan-feng, LI Chun-qi, WAN Li-ning. Analysis of nitrogen content control in Al-killed steel[J]. China Metallurgy, 2021, 31(3): 116-121.
Yu S,Miettinen J,Louhenkilpi S.Modeling study of nitrogen removal from the vacuum tank degasser[J].Steel Research International,2014,85:1393.
[2]
Holappa L.Treatise on Process Metallurgy: Secondary Steelmaking[M].Kidlington:Elsevier Ltd.,2014.
[3]
Ono H,Iuchi K,Morita K,et al.Effects of oxygen and nitrogen on the rate of nitrogen dissolution in iron-chromium and iron-vanadium alloys[J].ISIJ International,1996,36:1245.
[4]
Morita K,Hirosumi T,Sano N.Effects of aluminum,silicon,and boron on the dissolution rate of nitrogen into molten iron[J].Metall Mater Trans B,2000,31:899.
[5]
Numata M,Higuchi Y,Fukagawa S.Change of nitrogen content in the molten steel during cao powder blowing[J].Steel Research International,2003,74: 26.
[6]
Yamanaka R,Ogawa K,Iritani H,et al.Denitrogenization mechanism from molten steel by flux treatment[J].ISIJ International,1992,32:136.
[7]
Steinmetz E,Scheller P R.Fundamentals of nitrogen transfer in gas-metal bath systems during nitrogen injection[J].Steel Research,1987,58: 303.
[8]
Steinmetz E,Scheller P R.Kinetics of mass transfer during nitrogen injection in industrial Fe-Cr-Ni-Mo-melts[J].Steel Research,1987,58: 310.
[9]
Kitamura T,Miyamoto K,Tsujino R,et al.Mathematical model for nitrogen desorption and decarburization reaction in vacuum degasser[J].ISIJ International,1996,36:395.
[10]
Takahashi F,Momoi Y,Kajikawa K et al.Nitrogen solubility and rate of nitrogen absorption and desorption in high cr steel under pressurized atmosphere[J].Tetsu-to-Hagané,2011,97:525.
[11]
Takahashi M,Matsuda H,Sano M,et al.Rate of nitrogen desorption from molten iron by ar gas injection[J].Tetsu-to-Hagané,1986,72:419.
[12]
Inomoto T,Kitamura S Y,Yano M.Kinetic study of the nitrogen removal rate from molten steel (normal steel and 17 mass%Cr steel) under CO boiling or argon gas injection[J].ISIJ International,2015,55:1822.
[13]
Thoms A,Tu S,Janke D.Denitrogenation of steel melts with oxygen and sulphur by injection of argon under reduced pressure[J].Steel Research,1997,68: 475.
[14]
Sasabe M.Improvement in secondary refining technology and the realizability in the decrease of the impurity[C]//90-91th Nishiyama Memorial Lecture.Tokyo:[s.n.],1991:50.
[15]
Kobayashi A,Tsukihashi F,Sano N.Kinetic studies on the dissolution of Nitrogen into molten iron by 14 N-15 N isotope exchange reaction[J].ISIJ International,1993,33:1131.
[16]
Hino M,Ito K.Japan Society for the Promotion of Science and the 19th Committeeon Steelmaking: Thermodynamic Data for Steelmaking[M].Sendai:Tohoku University Press,2010.
[17]
Kamesui A,Furuno Y,Teraoka T,et al.Prevention of Nitrogen suction during RH treatment[J].Camp-ISIJ,1994,7:243.