Decarburisation of bainitic ferrite laths and its influence on the microstructure in Fe-Cr-Si-C steel

• Autorzy: Ławrynowicz Z.
• Języki publikacji: EN

Abstrakty

EN

The paper presents an investigation of the time required for the diffusion of carbon out of supersaturated laths of ferrite into the retained austenite. 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. 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 with the reference to the executed thermal processing 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; bainite reaction

• Wydawca: Politechnika Gdańska
• Czasopismo: Advances in Materials Science
• Rocznik: 2011
• Tom: Vol. 11, nr 2(28)
• Strony: 56--64
• 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. Chang L.C.: Carbon content of austenite in austempered ductile iron. Scripta Materialia 39 (1998), 35-38.
• 2. Pietrowski S.: Nodular cast iron of bainitic ferrite structure with austenite or bainitic structure. Archives of Materials Science 18 (1997), 253-273. (in Polish)
• 3. Guzik S.E.: Austempered cast iron as a modern constructional material. Inżynieria Materiałowa 6 (2003), 677-680. (in Polish).
• 4. Bhadeshia H.K.D.H.: Bainite in Steels, Institute of Materials, 1-458, London, 1992.
• 5. Bhadeshia H.K.D.H., Christian J.W.: Bainite in Steels. Metallurgical Transactions A 21A (1990), 767-797.
• 6. Ławrynowicz Z.:, Mechanism of bainite transformation in Fe-Cr-Mo-V-Ti-C steel. International Journal of Engineering 12 (1999), 81-86.
• 7. Takahashi M., Bhadeshia H.K.D.H.:, A Model for the Microstructure of Some Advanced Bainitic Steels. Materials Transaction, JIM 32 (1991), 689-696.
• 8. Bhadeshia H.K.D.H.: Diffusion of carbon in austenite. Metal Science 15 (1981), 477-479.
• 9. 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 1 (1970), 985-988.
• 10. Kinsman K.R., Aaronson H.I.: The transformation and hardenability in steels, Climax Molybdenum Company, Ann Arbor, MI, p.39, 1967
• 11. Ławrynowicz Z.: Transition from upper to lower bainite in Fe-Cr-C steel. Materials Science and Technology 20 (2004), 1447-1454.
• 12. Christian J.W.: Theory of transformations in metals and alloys, 778, Oxford, Pergamon Press, 1965.
• 13. Kutsov A. at al.: Formation of bainite in ductile iron. Materials Science and Engineering A273-275 (1999), 480-484
• 14. Ławrynowicz Z.: A discussion on the mechanism of bainite transformation in steels. Technology and Materials. Gdańsk, Politechnika Gdańska 4 (2006), 149-155 (in Polish).
• 15. Shiflet G.J., Hackenberg R.E.: Partitioning and the growth of bainite. Scripta Materialia 47 (2002), 163-167.
• 16. Ławrynowicz Z.: Criticism of selected methods for diffusivity estimation of carbon in austenite. Zeszyty Naukowe ATR nr 216, Mechanika 43 (1998), 283-287. (in Polish).