Kinetic Description of (Cr, Fe)₇C₃ Carbide Dissolution in Austenite of High-Carbon Fe-Cr-C Ternary Alloys

Abstract:

The paper examines the available experimental data to produce a model for quantitative prediction of the change of M₇C₃ carbide fraction and austenite chemical composition during holding of ternary alloys Fe–Cr–C (used as wear-resistant white cast irons and tool steels) in austenite + carbide region. Carbide dissolution is well described by Avrami type equation with exponent n close to 1/2. Dependences of the coefficient of this equation on carbide fraction and of the activation energy of the temperature dependence of this coefficient on carbide composition are established. As a result, a model that permits to calculate the fraction and chemical composition of austenite and M₇C₃ carbide in an Fe–Cr–C alloy of arbitrary composition after isothermal holding at given temperature for given time is obtained; equilibrium phase composition is needed to be known from thermodynamic models. This allows predicting the results of hardening after different austenitization regimes.

• Periodical: Materials Science Forum (Volume 870)
• Pages: 409-415
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.870.409
• Online since: September 2016
• Authors: A.S. Sozykina, K.Yu. Okishev*, A.G. Grebenshchikova, D.A. Mirzaev
• Keywords: Austenitization, Chromium Cast Irons, Dissolution, Hardness, Heat Treatment, Kinetics, M₇C₃ Chromium Carbide

References

[1] I.I. Tsypin, White Wear-Resistant Cast Irons: Structure and Properties, Metallurgiya Publ., Moscow, 1983. (in Russ. ).

[2] A.A. Zhukov, G.I. Sil'man, M.S. Frol'tsov, Wear-Resistant Castings of Complex Alloy White Cast Irons, Mashinostroenie Publ., Moscow, 1984. (in Russ. ).

[3] D.A. Mirzaev, N.M. Mirzaeva, A.N. Emelyushin, Ledeburite alloys for tools for machining of graphite, Metal Science and Heat Treatment. 30 (1988) 519-523. DOI: 10. 1007/BF00777442.

DOI: 10.1007/bf00777442

[4] A.N. Emelyushin, D.A. Mirzaev, N.M. Mirzaeva, E.V. Petrochenko, N.V. Koptseva, Metal Science, Physics and Mechanics Applied to Working of Graphitized Materials, Structure and Wear Resistance of Tools, MGTU Publ., Magnitogorsk, 2002. (in Russ. ).

[5] A.N. Emelyushin, D.A. Mirzaev, N.M. Mirzaeva, E.V. Petrochenko, K. Yu. Okishev, O.S. Molochkova, Cast Tools of Chromium Cast Irons, Structure and Properties, MGTU Publ., Magnitogorsk, 2016. (in Russ. ).

[6] Yu.A. Geller, Tool Steels, Metallurgiya Publ., Moscow, 1983. (in Russ. ).

[7] G. Krauss, Steels: Heat Treatment and Processing Principles, ASM International, (1990).

[8] K. Yu. Okishev, A.S. Sozykina, Structure and hardness changes with hardening temperature in high-chromium steels and cast irons, Bull. of the South Ural State Univ. Ser. Metallurgy. 16 (2011) 67-70. (in Russ. ).

[9] Yu.D. Koryagin, K. Yu. Okishev, A.S. Sozykina, Optimization of chemical composition and heat treatment of high-carbon iron alloys with 14 % chromium and 3 % vanadium, in: Proceeding of Materials Science Forum. 843 (2016).

DOI: 10.4028/www.scientific.net/msf.843.111

[10] C. Zener, Kinetics of the decomposition of austenite, Trans. AIME. 167 (1946) 550-583.

[11] M. Hillert, Solid state phase transformations, Jernkontoret Annaler. 141 (1957) 757-790.

[12] C. Wert, C. Zener, Interference of growing spherical precipitate particles, J. Appl. Phys. 21 (1950) 5-8. DOI: 10. 1063/1. 1699422.

DOI: 10.1063/1.1699422

[13] J.W. Christian, The Theory of Transformations in Metals and Alloys, Pt. I. Elsevier Sci. Ltd., 2002. DOI: 10. 1016/B978-008044019-4/50016-7.

[14] B. -J. Lee, On the stability of Cr carbides, CALPHAD. 16 (1992) 121-149. DOI: 10. 1016/0364-5916(92)90002-F.

DOI: 10.1016/0364-5916(92)90002-f

[15] A.W. Bowen, G.M. Leak, Solute diffusion in alpha- and gamma-iron, Metallurgical Transactions. 1 (1970) 1695-1700. DOI: 10. 1007/BF02642019.

DOI: 10.1007/bf02642019

[16] P.L. Gruzin, Diffusion of cobalt, chromium and tungsten in iron and steel, Doklady AN SSSR. 94 (1954) 681-684. (in Russ. ).

[17] S. Gertsriken, I. Dekhtyar, Investigation of chromium diffusion in iron-chromium alloys with impurities, Zhurnal Tekhnicheskoy Fiziki. 20 (1950) 1005-1014. (in Russ. ).

[18] K. Nakazawa, Effect of austenitic state on the Ms point of hypereutectoid alloy steel, J. Japan Inst. Metals and Materials. 27 (1963) 245-250.

DOI: 10.2320/jinstmet1952.27.6_245

[19] M. Hansen, K. Anderko, Constitution of Binary Alloys, McGraw-Hill Book Co., (1958).

[20] F. Maratray, R. Usseglio-Nanot, Atlas: transformation curves White iron chromium and chromium-molybdenum, Climax Molybdenum S.A., Paris, (1970).

[21] D.A. Mirzaev, Yu.D. Koryagin, A.A. Kulikov, A.S. Sozykina, Heat Treatment of Castings from White Wear-Resistant Cast Iron, Bull. of the South Ural State Univ. Ser. Metallurgy. 13 (2013) 111-115.

[22] Ya.R. Rauzin, Heat Treatment of Chromium Steel, Mashinostroenie Publ., Moscow, 1978. (in Russ. ).

[23] V.S. Popov, N.N. Brykov, N.S. Dmitrichenko, P.G. Pristupa, Durability of Refractory Brick Production Equipment, Metallurgiya Publ., Moscow, 1978. (in Russ. ).