Abstract




 
   

IJE TRANSACTIONS B: Applications Vol. 15, No. 3 (October 2002) 261-272   

downloaded Downloaded: 433   viewed Viewed: 2301

  GRAPHITE PHASE FORMATION IN AL ALLOYED DUCTILE IRONS
 
 
A. R. Kiani Rashid

Department of Materials, University of Sistan and Baluchestan
Zahedan, Iran, fkiana@yahoo.com

D. V. Edmonds

Department of Materials, University of Leeds
Leeds, UK, D.V.Edmonds@leeds.ac.uk

 
 
( Received: June 29, 2001 – Accepted in Revised Form: May 18, 2002 )
 
 

Abstract    The influence of aluminum, within the range of 0.08 - 6.16 wt.%, on the microstructure and hardness of as-cast ductile cast iron has been studied. A number of irons of different composition have been made by green sand casting and gravity die casting of appropriate design to provide the experimental materials. It has been found that Al addition and higher cooling rates in permanent mould casting both promote pearlite formation in the as-cast irons. Detailed microscopic observation revealed that foreign particles (with a high concentration of Al, Si and Mg) within the graphite spherulites probably behaved as nucleation sites, and that Al addition can promote spheroidal graphite nucleation and growth. Furthermore, it was illustrated that spherulites with a fan-like structure consist of aggregates of graphite platelets and interplatelet regions.

 

Keywords    Ductile Cast Iron, Spherulite, Graphene, Aggregation Layers, Foreign Particles, Pearlite Formation

 

References   

1. Hughes, I. C. H., Ductile Iron, "Metals Handbook", Casting, BCIRA International Center for Cast Metals Technology, Great Britain, Ninth Edition, Vol. 15, (1988), 647-666.
2. Angus, H. T., "Cast Iron", Physical and Engineering Properties, Butterworths and Co (Publishers) Ltd., London, (1978).
3. Elliot, R., "Cast Iron Technology", Butterworths and Co. (Publishers) Ltd., London, (1988).
4. Morrogh, H. and Williams, W. J., "Graphite Formation in Cast Irons", J. Iron and Steel, Vol. 155, (1947), 323-370.
5. Morrogh, H. and Williams, W. J., "The Production of Nodular Graphite Structures in Cast Iron", JISI, (March 1948), 306-322.
6. Zhukov, A. A, "Thermodynamics of Structure Formation in Cast Iron Alloyed with Graphitizing Elements", Metal Forum, 2, 1979, 127-136.
7. Defrancq, C., Van Fegham, J. and Desy A., "Study of the Inoculation of Gray Cast Irons from the Fe-C-Al System: Development of a New Flake Graphite Cast Iron with Very High Strength", 36th International Foundry Congress, Belgrad, (1969), 112-119.
8. Walson, R. P., "Aluminum Alloyed Cast Iron Properties Used in Design", AFS Transactions, 85, (1977), 51-58.
9. Smickley, R. J. and Rundman, K. B., "The Effect of Aluminum on the Structure and Properties of Gray Cast Iron", AFS Transactions, 89, (1981), 205-214.
10. Boutorabi, S. M. A., "The Austempering Kinetics Microstructure and Mechanical of Spheroidal Graphite Unalloyed Aluminum Cast Iron", Ph.D. Thesis, University of Birmingham, (May 1991).
11. Boutorabi, S. M. A., Young, J. M., Kondic, V. and Salehi, M., "The Tribiological Behavior of Austempered Spheroidal Graphite Aluminum Cast Iron", Wear, (Switzerland), Vol. 165, No.1, (May 1993d), 19-24.
12. Double, D. D. and Hellawell, A., "The Structure of Flake Graphite in Ni-C Eutectic Alloy", Ada Metallurgical, Vol. 17, (August 1969), 1071-1083.
13. Double, D. D. and Hellawell, A., "The Nucleation and Growth of Graphite, The Modification of Cast Iron", Acta Metall. Mater., Vol. 43, No. 6, (1995), 2435- 2442.
14. Baihe Miao, Kerning Fang, Weimin Bian and Guoxun liu, "On the Microstructure of Graphite Spherulites in Cast Irons by TEM and HREM", Ada Mdall. Mater., Vol. 38, No. 11, (1990), 2167-2174.
15. Baihe Miao, North Wood, D. 0., Weimin Bian, Kerning Fang and Minz Heng Fan., "Structure and Growth of Platelets in Graphite Spherulites in Cast Iron", Journal of Materials Science, 29, (1994), 255-261.
16. Katz, S. and Spironello, V. R., "Effect of Charged Aluminum on Iron Temperature, Silicon Recovery and Desulphurisation in an Iron Producing Cupola", A.F.S. Trans.,92,(1984), 161.
17. Boutorabi, S. M. A., Young, J. M. and Kondic, V., "Hardness and Tensile Properties of Austempered Aluminum Containing Ductile Iron", International Journal of Cast Metals Research (UK), Vol. 6, No. 3, (1993c), 170-174.
18. Kiani-Rashid, A. R., "The Influence of Aluminum and Heat Treatment Conditions on Austempered Ductile Irons", Ph.D. Thesis, University of Leeds, (July 2000).
19. Weis, W., "Development of Theories on Graphite Formation in Ductile Cast Iron", International Symposium over de Metallurgie van Gietijzer, Geneve, Giesserei, (1974), 475.





International Journal of Engineering
E-mail: office@ije.ir
Web Site: http://www.ije.ir