Macrosegregation of Alloying Elements in Hot Top of Large Size High Strength Steel Ingot

Abstract:

The chemical heterogeneities of alloying elements were evaluated in the hot top plus the top of a 40-ton ingot of as-cast high strength low alloy steel. The chemical compositions of small samples, taken from a slice cut along the longitudinal axis of the ingot, were obtained using mass spectroscopy. The chemical results were used to construct the chemical heterogeneity maps of C, Mn, Ni, Cr and Mo in the entire slice. The analyses of the different maps indicate the existence of positive segregation for all segregated elements except Ni where no segregation was observed. The most important macrosegregation was revealed in the centerline of the ingot. Carbon presents the highest degree of segregation whereas Mo presents the lowest one. In term of homogeneity degrees, Mn, Ni, Cr and Mo present better homogeneity than C whether in the top of the ingot or in the hot top.

• Periodical: Materials Science Forum (Volume 879)
• Pages: 1176-1181
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.879.1176
• Online since: November 2016
• Authors: Abdelhalim Loucif*, Davood Shahriari, Chunping Zhang, Mohammad Jahazi, Louis Philippe Lapierre-Boire, Rami Tremblay
• Keywords: As-Cast Ingot, High Strength Steel, Hot Top, Positive Macrosegregation

References

[1] E. J. Pickering, Macrosegregation in Steel Ingots: The applicability of modelling and characterisation techniques, ISIJ International, 53 (2013) 935-949.

DOI: 10.2355/isijinternational.53.935

[2] R. Nadella, D.G. Eskin, Q. Du, L. Katgerman, Macrosegregation in direct-chill casting of aluminium alloys, Prog. Mater Sci. 53 (2008) 421-480.

DOI: 10.1016/j.pmatsci.2007.10.001

[3] A. Loucif, E. Ben Fredj, M. Jahazi, L-P. Lapierre-Boire, R. Tremblay, R. Beauvais, Analysis of macrosegregation in large size forged ingot of high strength steel, Proceeding of the 6th International Congress on the Science and Technology of Steelmaking (ICS2015), Beijing (China), (May 12-14, 2015) 1043-1046.

DOI: 10.4028/www.scientific.net/msf.879.1176

[4] J. Campbell, Castings, second ed., Butterworth-Heinemann, Oxford, (2003).

[5] M. Torabi Rad, P. Kotas, C. Beckermann, Rayleigh number criterion for formation of A-segregates in steel castings and ingots, Metall. Mater. Trans. A. 44A (2013) 4266-4281.

DOI: 10.1007/s11661-013-1761-4

[6] M. Wu, J. Li, A. Kharicha, A. Ludwig, Using a three-phase mixed columnar-equiaxed solidification model to study macrosegregation in ingot castings: perspectives and limitations, Proceeding of the 2013 International symposium on liquid metal processing & casting, Edited by M. J. M. Krane, A. Jardy, R. L. Williamson, J. J. Beaman, TMS (2013).

DOI: 10.1002/9781118830857.ch26

[7] E. J. Pickering, H. K. D. H. Bhadeshia, The consequences of macroscopic segregation on the transformation behavior of a pressure-vessel steel, J Press Vessel Technol, 136 (2014) 031403-1-031403-7.

DOI: 10.1115/1.4026448

[8] S. Qian, X. Hu, Y. Cao, X. Kang, D. Li, Hot top design and its influence on feeder channel segregates in 100-ton steel ingots, Mater. Des. 87 (2015) 205-214.

DOI: 10.1016/j.matdes.2015.07.150

[9] E. J. Pickering, C. Chesman, S. Al-Bermani, M. Holland, P. Davies, J. Talamantes-Silva, A comprehensive case study of macrosegregation in a steel ingot, Metall. Mater. Trans. B. 46B (2015) 1860-1874.

DOI: 10.1007/s11663-015-0386-y

[10] G. E. Totten, L. Xie, K. Funatani, Handbook of mechanical alloy design, Marcel Dekker, Inc., New York Basel, (2004).