Methodology of mass-exchange processes calculation in steel SA-20A alloying by nitrogen during blow through bottom tuyeres
| Autor: | A. Yu. Kem, A. A. Kozhukhov, E. Yu. Rosechupkina |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Ferrous Metallurgy. Bulletin of Scientific , Technical and Economic Information. 76:463-470 |
| ISSN: | 2619-0753 0135-5910 |
| DOI: | 10.32339/0135-5910-2020-5-463-470 |
| Popis: | To alloy steel by nitrogen, any material containing nitrogen in necessary amount and being capable to dissolve in the liquid metal, can be used. Methods of alloying by nitrogen, based on melt blowing through by gaseous nitrogen are known. However to carry out this process it is necessary to have a qualitative estimation of nitrogen behavior at various stages of steelmaking process. It is also necessary to have reliable data on the nitrogen assimilation speed and conditions of its interaction with other melt components. Therefore, elaboration of a methodology of estimation of nitrogen assimilability under conditions of blowing through with stirring and thermo-dynamic conditions of vanadium nitrides formation in the steel SA-20A is rather actual. In the course of methodology elaboration, equilibrium nitrogen concentration was determined accounting parameters of interaction, calculation of stirring power and nitrogen assimilability under set conditions of blowing through were accomplished. Besides, calculations were accomplished on average effective “bubble” coefficient of mass-transfer of nitrogen to liquid steel; duration of blow through by nitrogen under conditions of stirring and thermo-dynamic conditions of VN nitrides formation under equilibrium and industry conditions. The effect of mass-transfer speed on the nitrogen assimilability by steel was shown. It was determined, that blow through parameters and first of all, gaseous nitrogen consumption are determined by a number of bubbles and the area of their surface. Results of the elaborated methodology testing presented. The necessity of specifying the methodology of estimation of gas bubbles evolution in the process of their moving during the bottom blow through justified. Comparison of the obtained data with the industrial data were confirmed by the sufficiency of nitrogen concentration in steel SA-20A for realization of the nitride hardening process. |
| Databáze: | OpenAIRE |
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