Maximization and Control of Nodular Iron Melt’s Self-Feeding Characteristics to Minimize Shrinkage

Abstract:

This paper describes one possible method to anticipate and control the development of solidification shrinkage, during solidification of nodular cast iron melts, based upon industrial trials made using special designed test castings and closed volume thermal analysis cartridges.The methodology considers both the solidification morphology and solidification shrinkage critical size, which is always a difficult component of analysis, along with a developed contraction defect index, that allows the application to several types of molten metal and inoculation practices.The use of thermal analysis allows the recognition of unique melt characteristics, in real time, that are not accessed by more traditional measurement equipment. This allows the definition of thermal analysis patterns that characterize the best melt quality for self-feeding. This is a practical to use and powerful tool for modern foundries, taking advantage of new metric, data collection and data analysis. We aim to contribute to scientific knowledge and simultaneously to provide information that can be useful for foundries to improve their process efficiency.

• Periodical: Materials Science Forum (Volume 925)
• Pages: 147-154
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.925.147
• Online since: June 2018
• Authors: Vítor Anjos*, Carlos A. Silva Ribeiro
• Keywords: Nodular Cast Iron, Pattern Yield, Self-Feeding, Solidification Morphology, Thermal Analysis

References

[1] D. M. Stefanescu, Science and Engineering of Casting Solidification, Springer Science+Business Media, New York, 2009, pp.1-4.

[2] S. Hasse, Guß- und Gefügefehler, Schiele & Schön GmbH, Berlin, (2003).

[3] I. Jimbo and A. W. Cramb, The density of liquid iron-carbon alloys, submitted to Metall. Mater. Trans. A, 24 (1993), pp.5-10.

[4] R. Hummer, Beurteilung der Lunkerneigung von Gußeisen mit Kugelgraphit mittels Abkühl- und Längeänderungskurven, submitted to Giesserei-Praxis Nr.9/10, pp.142-151, (1989).

[5] Z. Gedeonová, J. Dúl and S. Bódi, Die Bewegung der Grenzfläche Metall/Form Wärend der Erstarrung von Gußeisen mit Kugelgraphit und Lamellengraphit, submitted to Gießerei-Praxis Nr. 7/8, pp.150-155, (1996).

[6] W. Schmitz and S. Engler, Ausdehnungsdrücke während der Erstarrung von Gußeisen mit Lamellen- und Kugelgraphit, submitted to Giesserei 77 (11) (1990), 372-375.

[7] J. Zhou, Colour Metallography of Cast Iron - Chapter 1 Introduction (I), submitted to China Foundry , vol. 6, pp.57-65, (2009).

[8] W. R. Heine, The Fe-C-Si Solidification Diagram for Cast Iron, AFS Transactions, 1986, 391-403.

[9] G. Lesoult, M. Castro and J. Lacaze, Solidification of Spheroidal Graphite Cast Irons - I Physical Modelling, submitted to Acta Metall., 46 (3) (1998), 983-995.

DOI: 10.1016/s1359-6454(97)00281-4

[10] W. Baumgart, Untersuchung des Phasenübergangs von flüssig nach fest am tertiären System Fe-C-Si unter Nichtgleichgewichtsbedingungen, submitted to Lehrstuhl für das gesamte Gießereiwesen und Gießerei-Institut der RWTH Aachen, Aachen, (2013).

[11] V. Anjos, Use of Thermal Analysis to Control the Solidification Morphology of Nodular Cast Irons and Reduce Feeding Needs" Submitted for PhD thesis at Universität Duisburg-Essen, Duisburg, (2015).

[12] V. Anjos, C. S. Ribeiro, J. Cunha and C. Gomes, The use of thermal analysis to compare solidification pattern, and evaluate performance, of several inoculants, in ductile iron., submitted in 71st World Foundry Congress, Bilbao, (2014).