Affect of decarburization times of bainitic ferrite laths on the microstructure in FE-CR-C steel

• Autorzy: Ławrynowicz Z.
• Języki publikacji: EN

Abstrakty

EN

The purpose of the present paper is to demonstrate how a thermodynamic method can be used for solving a problem of the decarburisation of bainite laths. The paper presents an investigation of the time required for the diffusion of carbon out of supersaturated laths of ferrite into the retained austenite. This should in principle enable to examine the partitioning of carbon from supersaturated ferrite laths into adjacent austenite and the carbon content in retained austenite using analytical method. The obtained results illustrates that the estimated times are not capable of decarburising the sheaf of ferrite included thick laths of bainitic ferrite during the period of austempering. A consequence of the precipitation of cementite from austenite during austempering is that the growth of bainitic ferrite can continue to larger extent and that the resulting microstructure is not an ausferrite but it is a mixture of bainitic ferrite, retained austenite and carbides.

Słowa kluczowe

EN

carbon diffusion; decarburisation

• Wydawca: Faculty of Ocean Engineering and Ship Technology, Gdańsk University of Technology
• Czasopismo: Journal of Polish CIMAC
• Rocznik: 2011
• Tom: Vol. 6, no 3
• Strony: 127--136
• Opis fizyczny: Bibliogr. 16 poz., rys., tab.

Twórcy

autor

Ławrynowicz Z.

• University of Technology and Life Sciences, Mechanical Engineering Faculty, Department of Materials Science and Engineering av. Kaliskiego 7, 85-789 Bydgoszcz, Poland,

Bibliografia

• [1] Bhadeshia, H.K.D.H., Diffusion of carbon in austenite, Metal Science, vol. 15, 477-479, 1981.
• [2] Bhadeshia, H.K.D.H., Christian, J.W., Bainite in Steels, Metallurgical Transactions A, 21A, 767-797, 1990.
• [3] Bhadeshia, H.K.D.H., Bainite in Steels, Institute of Materials, 1-458, London, 1992.
• [4] Chang, L.C., Carbon content of austenite in austempered ductile iron, Scripta Materialia, vol. 39, No 1, 35-38, 1998.
• [5] Christian, J.W., Theory of transformations in metals and alloys, p. 778, Oxford, Pergamon Press, 1965.
• [6] Guzik, S.E., Austempered cast iron as a modern constructional material, Inżynieria Materiałowa, vol. 6, 677-680, 2003.
• [7] Kinsman, K.R., Aaronson, H.I., The transformation and hardenability in steels, Climax Molybdenum Company, Ann Arbor, MI, p.39, 1967.
• [8] Kutsov, A. at al., Formation of bainite in ductile iron, Materials Sci. and Engineering, A273-275, 480-484, 1999.
• [9] Ławrynowicz, Z., Criticism of selected methods for diffusivity estimation of carbon in austenite, Zeszyty Naukowe ATR, nr 216, Mechanika, vol. 43, 283-287, 1998.
• [10] Ławrynowicz, Z., Mechanism of bainite transformation in Fe-Cr-Mo-V-Ti-C steel, International Journal of Engineering, vol. 12, 81-86, 1999.
• [11] Ławrynowicz, Z., Transition from upper to lower bainite in Fe-Cr-C steel, Materials Science and Technology, vol. 20, 1447-1454, 2004.
• [12] Ławrynowicz, Z., A discussion on the mechanism of bainite transformation in steels, Technology and Materials,. Gdańsk, Politechnika Gdańska, vol. 4, pp. 149-155, 2006.
• [13] Pietrowski, S., Nodular cast iron of bainitic ferrite structure with austenite or bainitic structure, Archives of Materials Science, vol. 18, No.4, 253-273, 1997.
• [14] Shiflet, G.J., Hackenberg, R.E., Partitioning and the growth of bainite, Scripta Materialia, vol. 47, 163-167, 2002.
• [15] Siller, R.H., McLelan, R.B., The Application of First Order Mixing Statistics to the Variation of the Diffusivity of Carbon in Austenite, Metallurgical Transactions, vol. 1, 985-988, 1970.
• [16] Takahashi, M., Bhadeshia, H.K.D.H., A Model for the Microstructure of Some Advanced Bainitic Steels, Materials Transaction, JIM, vol. 32, 689-696, 1991.