Cooling Rate Dependence of STructures Characteristics in Ce-Inoculated Low-S Grey Irons
Abstract
The efficiency of Ce,Ca,Al-FeSi alloy was tested for lower addition rates (0.15-0.25wt.%), as, traditionally, high inoculant addition rates have been used in low sulphur grey cast irons, comparing to the base iron and conventional inoculated irons (Ba,Ca,Al-FeSi commercial alloy). The present work explores chill and associated structures in hypoeutectic grey iron chill wedges, with cooling modulus 0.21 cm and a large variation of the cooling rate, from the apex to the base of W2 samples [ASTM A 367, furan resin mould]. The chill tendencies of the experimental irons correlate well with the structure characteristics, displayed as the carbides/graphite ratio of undercooled graphite morphologies. Carbide sensitivity is lower with increasing wedge width, but depends on whether the state of the iron is as base iron or inoculated with different alloys. Undercooled graphite was present for both un-inoculated irons and higher cooling rate inoculated irons. As expected, inoculation as well as an increase in wall thickness of the same wedge sample led to improved undercooled graphite control. The difference in effects of the two inoculants addition is seen as the ability to decrease the amount of carbides and undercooled graphite, with Ce-bearing FeSi alloy outperforming the conventional inoculant, especially at the low alloy addition and high cooling rate solidification.
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References
[2]. I. Riposan, M. Chisamera, S. Stan, T. Skaland -Graphite Nucleants (Microinclusions) Characterization in Ca/Sr Inoculated Grey Irons. Int. J. Cast Met. Res., 2003, Vol. 16, No. 1-3, pp. 105-111.
[3]. I. Riposan, M. Chisamera, S. Stan, C. Hartung, D. White. Three-Stage Model for the Nucleation of Graphite in Grey Cast Iron. Mater. Sci. Techn., 2010, Vol. 26, No. 12, pp. 1439-1447.
[4]. I. Riposan, M. Chisamera, S. Stan, C. Ecob, D. Wilkinson - Role of Al, Ti, Zr in Grey Iron Preconditioning/Inoculation. J. Mater. Eng. Perform., 2009, Vol. 18 (1), pp. 83-87.
[5]. R. Gundlach - Observations on Structure Control to Improve the Properties of Cast Irons. The 2008 Honorary Cast Iron Lecture, Div. 5, AFS Metalcasting Congress, Atlanta, Georgia, USA, Paper 08-158.
[6]. C. Hartung, C. Ecob, D. Wilkinson - Improvement of Graphite Morphology in Cast Iron. Casting Plant and Technology International, 2008, No. 2, pp. 18-21.
[7]. Cast iron inoculation, The Technology of Graphite Shape Control Brochure, Information on www.foundry.elkem.com, May 2009.
[8]. I. Riposan, M. Chisamera, S. Stan, G. Grasmo, C. Hartung, D. White - Iron Quality Control During Melting in Coreless Induction Furnace. AFS Trans., 2009, Vol. 117, pp. 423-434.
[9]. M. Chisamera, I. Riposan, S. Stan, C. Ecob, G. Grasmo, D. Wilkinson - Preconditioning of Electrically Melted Gray Cast Irons. AFS International Cast Iron Melting Conference, February 21-23, 2009, Orlando, Florida, USA.
[10]. Reseed® Inoculant–ELKEM Foundry Products Division Brochure. Information on http:// www.foundry.elkem.com (2004).
[11]. I. Riposan, M. Chisamera, S. Stan, E. Stefan, C. Hartung - Role of Lanthanum in Graphite Nucleation in Grey Cast Iron. Key Engineering Materials-KEM, Vol.457 [Science and Processing of Cast Iron IX], (2011), pp. 19-24. Trans. Techn. Publications, Switzerland.
[12]. I.V. Anton, I. Riposan - Structure Characteristics of CeInoculated, Low Sulphur Grey Cast Irons. Advanced Materials and Structures - AMS '11 International Conference, Timisoara, Romania, Oct. 2011, Paper-045.
[13]. S. Stan, M. Chisamera, I. Riposan, E. Stefan, M. Barstow - Solidification Pattern of Un- inoculated and Inoculated Gray Cast Irons in Wedge Test Samples. AFS Trans., 2010, Vol. 118, p. 295-309.
