Thermodynamic Modeling of Phase Equilibrium in Fe-Y-Cr-C-O Liquid Metal System

Abstract:

The thermodynamic characteristics of processes in the liquid metal system Fe–Y–Cr–C–O are considered as applied to low-carbon and low-alloy metal. The critical parameters for the state diagram of the oxide system Y₂O₃–Cr₂O₃ were established based on the values quoted in literature. The temperature dependence of the melting reaction constant Y₂O₃·Cr₂O₃ was determined. The coordinates of eutectic transformation points for the system Y₂O₃–Cr₂O₃ were calculated. In accordance with subregular solution theory, the energetic parameters which are necessary to calculate the activities Cr₂O₃ and Y₂O₃ of oxide melts in the system Y₂O₃–Cr₂O₃ were determined. The energetic parameters of subregular solution theories for the oxide system FeO–Cr₂O₃–Y₂O₃ were determined based on the values for the binary systems FeO–Y₂O₃, FeO–Cr₂O₃ and Y₂O₃–Cr₂O₃. The view of this diagram, as coupled with the existence domain of liquid metal within the framework of the quaternary system Fe–Y–Cr–O–С, suggests that low-carbon chromic liquid metal when injected with yttrium can form the following non-metallic inclusions: |Cr₂O₃|, |Y₂O₃|, |FeO·Cr₂O₃|, |Y₂O₃·Cr₂O₃| or oxide melt (FeO, Y₂O₃, Cr₂O₃). Oxide melt may contain up to 2 % of divalent chrome (Cr2+). The equilibrium constants for the main reactions of steel deoxidation with the formation of liquid, solid and gas products of chemical reactions were also established. The activity of components dissolved in metal was calculated using interaction parameters. The set of derived expressions for the activity of components and the dependences of equilibrium constants of chemical reactions and phase transformations allowed us to diagram the surface of component solubility in liquid metal (SCSM). SCSM diagrams show the compositions of liquid metal and indicate oxide phases which are in equilibrium with liquid metal.

• Periodical: Solid State Phenomena (Volume 265)
• Pages: 862-867
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.265.862
• Online since: September 2017
• Authors: Gennady G. Mikhailov*, Larisa A. Makrovets
• Keywords: Chrome, Deoxidation, Phase Equilibria, State Diagram, Thermodynamics, Yttrium

References

[1] V.A. Golubtsov, V.V. Lunev, Modification of Steel for Castings, Publisher: ZNTU, Chelyabinsk-Zaporozhye, (2009).

[2] I.V. Ryabchikov, Modifiers and technology secondary treatment of iron-carbon alloys, Ekomet, Moscow, (2008).

[3] V.V. Lunev, Yu.V. Shul'te, Using complex alloys with alkaline-earth and rare-earth elements to improve the properties of cast and deformed steel, Influence of Reduction on Steel Properties, Metallurgiya, Moscow, (1982) 33-50.

[4] Information on http: /www. urm. ru/ru/75-journal124-article64.

[5] V.V. Averin The application of REM in metallurgy of steel, Metallurgical ways of improving the quality of steel, Publisher Science, Moscow, (1979) 33-40.

[6] I.S. Kulikov Deoxidation metals, Metallurgy, Moscow, (1975).

[7] L.M. Lopato, L.I. Lugin, A.V. Shevchenko, Phase Relationships in Magnesium Oxide-Cerium Subgroup R.E.E. Oxide System. Russ. J. Inorg. Chem. 16(1) (1971), 131-133.

[8] H. Keune, Chimica – ein Wissensspeicher. Wiley-VCH Verlag GmbH & Co, KGaA, Weinheim, (1959).

[9] G.G. Mikhailov, D.J. Povolotskii, Thermodynamics of steel deoxidation, Metallurgy, Moscow, (1993).

[10] G.G. Mikhailov, B.I. Leonovich, Yu.S. Kuznetsov Thermodynamics of Metallurgical Processes and Systems. MISiS Publ., Moscow, (2009).

[11] N.A. Toropov, V.P. Barzakovskiy, V.V. Lapin, N.N. Kurtseva, Phase Diagrams of Silicate Systems, Binary Systems, Science, Leningrad, (1969).

[12] M. Hrovat, S. Bernik, J. Holc, D. Kolar, B. Dacar Preliminary data on subsolidus phase equilibria in the La2O3–Сr2O3–Y2O3 and La2O3–Сr2O3–ZrO2 systems, Journal of Materials Science Letters. 14 (1995) 1684-1687.

DOI: 10.1007/bf00422675

[13] G.G. Mikhailov, L.A. Makrovets, L.A. Smirnov, Thermodynamic Simulation of Phase Equlibria of Oxide Systems Containing Rare-Earth Metals, Phase Diagrams of Oxide Systems with Y2O3. Bulletin of the South Ural State University. Ser. Metallurgy, 14(4) (2014).

DOI: 10.14529/met150401

[14] G.G. Mikhailov, L.A. Chernova, Thermodynamic analysis of the processes of deoxidizing corrosion-resistant steel 18Cr10NiTi calcium and barium, Izvestiya vuzov. Ferrous metallurgy, 12 (1991) 37-40.

[15] Z. Busek, M. Macoszek, J. Szlauer Vliv prechodnych kovu na aktivitu a rozpustnost kysliku v zeleze pri 1600 °C. Hutnicke listy, 27(8) (1972) 547-557.

[16] Information on http: /steelcast. ru/first-order_interaction_coefficients.

[17] Yu.V. Balkovoy, R.A. Aleev, V.K. Bakanov, The parameters of the first order in the interaction of molten iron-base, Institute Chermetinformatsiya, Moscow, (1987).