An inoculation phenomenon in cast iron

Open access

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 analysed. We 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 modification of cast iron was studied.

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

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

[3] E. Fras, C. Podrzucki, Zeliwo modyfikowanwe, Skrypt AGH, nr. 675, Kraków 1978.

[4] E. Fras, Krystalizacja metali WNT, Warszawa 2003.

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

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

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

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

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

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

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

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

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

[14] B. Lux, Nucleation and graphite In Fe-C-Si alloys In Recent Research on Cast iron, Gordon and Breach, New York 1968, p. 241.

[15] E. Fras, H. Lopez, C. Podrzucki, The influence of oxygen on the inoculation process of cast iron, Journal Cast Metal Research 13, 107-121 (2000).

Archives of Metallurgy and Materials

The Journal of Institute of Metallurgy and Materials Science and Commitee on Metallurgy of Polish Academy of Sciences

Journal Information


IMPACT FACTOR 2016: 0.571
5-year IMPACT FACTOR: 0.776

CiteScore 2016: 0.85

SCImago Journal Rank (SJR) 2016: 0.347
Source Normalized Impact per Paper (SNIP) 2016: 0.740

Cited By

Metrics

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 151 112 13
PDF Downloads 82 67 4