Inoculation Effects of Cast Iron

Open access

Abstract

The paper presents a solidification sequence of graphite eutectic cells of A and D types, as well as globular and cementite eutectics. The morphology of eutectic cells in cast iron, the equations for their growth and the distances between the graphite precipitations in A and D eutectic types were analyzed. It is observed a critical eutectic growth rate at which one type of eutectic transformed into another. A mathematical formula was derived that combined the maximum degree of undercooling, the cooling rate of cast iron, eutectic cell count and the eutectic growth rate. One type of eutectic structure turned smoothly into the other at a particular transition rate, transformation temperature and transformational eutectic cell count. Inoculation of cast iron increased the number of eutectic cells with flake graphite and the graphite nodule count in ductile iron, while reducing the undercooling. An increase in intensity of inoculation caused a smooth transition from a cementite eutectic structure to a mixture of cementite and D type eutectic structure, then to a mixture of D and A types of eutectics up to the presence of only the A type of eutectic structure. Moreover, the mechanism of inoculation of cast iron was studied.

[1] Turner, T. (1920). The Metallurgy of Cast iron. Griffin Co.Ltd. London.

[2] Meehan, A. (1924). US Patent 1 499 068.

[3] Fraś, E. & Podrzucki, C. (1978). Żeliwo modyfikowane, Skrypt AGH, nr. 675, Kraków.

[4] Fraś, E. (2003). Krystalizacja metali WNT, Warszawa.

[5] Park, J. & Verhoven, J. (1996). Transitions between type A flake, type D flake and coral graphite eutectic structures in cast iron. Metallurgical and Materials Transactions A. 27A, 2740-2753.

[6] Fraś, E., Górny, M. & Lopez, H. (2005). The Transition from gray to white iron during solidification, part I - theoretical background. Metallurgical and Materials Transactions A. 36A, 3075-3082,

[7] Ohira, G., Sato, T. & Sayama, Y. (1974). Eutectic growthunidierectionally solidified iron-carbon alloys, Georgi Publishing Company, St. Shaporin, Switzeland, 296-313.

[8] Wołczyński, W. (2010). Lamella/Rod Transformation as described by the Criterion of Minimum Entropy Production. International Journal of Thermodynamics. 13 (2), 35-42.

[9] Magnin, P. & Kurz, W. (1988). Competitive growth of stable and metastable FE-C-X eutectics: Part II. Mechanism. MetallurgicalTransactions A. 19A, 1965-1971.

[10] Fraś, E. & López, H. (2010). Eutectic cells and nodule count - an index of molten iron quality. International Journal ofMetalcasting. Summer, 35-61.

[11] Fraś, E., Górny, M. & Lopez, H. (2007). Eutectic cell, chilling tendency and chill in flake graphite cast iron, part I - theoretical analysis. Transactions of American FoundrySociety. 115, 435-451.

[12] Fraś, E., Górny, M. & Lopez, H. (2007). Eutectic cell, chilling tendency and chill in flake graphite cast iron, part III - thermal analysis. Transactions of American FoundrySociety. 115, 476-480.

[13] Fraś, E. & López, H. (1994). Generation of internal pressure during solidification of eutectic cast iron. AFS Transactions. 102, 597-601.

[14] Lux, B. (1968). Nucleation and graphite In Fe-C-Si alloys InRecent Research on Cast iron, Gordon and Breach, New York, 241, [15] Fraś, E., Lopez, H. & Podrzucki, C. (2000). The influence of oxygen on the inoculation process of cast iron. Journal CastMetal Research. 13, 107-121.

Archives of Foundry Engineering

The Journal of Polish Academy of Sciences

Journal Information


CiteScore 2016: 0.42

SCImago Journal Rank (SJR) 2016: 0.192
Source Normalized Impact per Paper (SNIP) 2016: 0.316

Cited By

Metrics

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 158 158 11
PDF Downloads 84 84 10