Shrinkage Porosity Simulation of Spheroidal Graphite Iron Castings Based on Macro-Micro Models


Article Preview

Shrinkage porosity is often found in Spheroidal graphite iron (S. G. Iron) castings because of the mushy zone and special volume change during their solidification. Although the volume expansion is very important to the shrinkage porosity simulation of S.G. Iron castings, conventional methods for predicting the porosity defects do not consider it. A Series of macro-micro models such as macro heat transfer calculation and microstructure formation simulation are proposed to simulate the solidification of S. G. Iron castings. The nucleation and growth models are employed to calculate the accurate latent heat and volume change especially graphite expansion during the solidification. The pressure induced by graphite expansion is introduced as a parameter to predict the shrinkage porosity and a new shrinkage porosity criterion is developed. Cooling curves and solid fraction of each phase are compared with experimental castings. At the same time, the porosity area ratio of castings is compared with the results calculated by several porosity criterions. The results show that the new shrinkage porosity simulation criterion of S. G. Iron castings based on macro-micro models is accurate on shrinkage porosity shape, size and distribution simulation.



Edited by:

Enhou Han, Guanghong Lu and Xiaolin Shu






H. L. Zheng et al., "Shrinkage Porosity Simulation of Spheroidal Graphite Iron Castings Based on Macro-Micro Models", Materials Science Forum, Vol. 689, pp. 190-197, 2011

Online since:

June 2011




[1] M.J. Gough and J. Morgn, Feeding ductile iron castings-some recent experiments, AFS Transations, 1975, 84, 351-384.

[2] R. Wlodawer, Gelenkte Erstarrung von Gubeisen, (1977).

[3] S.I. Karsay, Ductile iron –gating and risering, QIT-Feret Titane Inc. , 1981, 121.

[4] E.F. Ryntz, R.E. Schroeder, W.W. Chaput, and W.O. Rassenfos, The formation of blowholes in spheroidal graphite cast iron castings, AFS Transaction, 1983, 91, 161-164.

[5] J.F. Wallce and P.K. Samal, Factors influencing a shrinkage cavity formation in ductile iron castings, AFS Transactions, 1984, 92, 765-784.

[6] R. Hummer, Feeding requirements and dilatation during solidification of spheroidal graphite cast iron-conclusions for feeder dimensioning, Gieberei-Praxis, 1985, 17, 241.

[7] H.J. Heine, Reducing porosity , Foundry management&Technology, 1992, Feb, 72-76.

[8] B.C. Liu, Progress in solidification modeling of cast iron in china. International journal of cast metal research. 1999, 11, 259-266.

DOI: 10.1080/13640461.1999.11819283

[9] I. Ohnaka, Progress in computer simulation of casting of spheroidal graphite cast iron in Japan, International journal of cast metal research. 1999, 11, 267-272.

DOI: 10.1080/13640461.1999.11819284

[10] Voller, V. R. and C. R. Swa , General source based method for solidification phase change. Numerical Heat Transfer, PartB. 1991, 19, 175-189.

DOI: 10.1080/10407799108944962

[11] Long sun Chao, Wu chang dong, Macro-Micro Modeling of Solidification, Proc. Natl. Sci. Counc. ROC(A), 1999, 23, 5, 622-629.

[12] Li. jiarong, B Liu, Proceedings of 61st World Foundry Congress, Beijing, China, 1995, InternationalAcademic Publishers, 41.

[13] J. Liu,R. Elliott. Numerical modeling of solidification of ductile iron[J]. Journal of crystal growth. 1998, 191, 261-267.

[14] Ahmd Almansour, Kazuhiro Matsugi, Tomei Hatayama and osamu yanagisawa, materials trans JIM Vol 36 no 12 1487~1495.

DOI: 10.2320/matertrans1989.36.1487

[15] Toshiro Owadano, Dr. Eng; Graphite nodule numbering spheroidal graphite and malleable cast iron, Imono, 1973; 193.

In order to see related information, you need to Login.