The role of silicon in the hot dip galvanizing process; pp. 159–165Full article in PDF format | doi: 10.3176/proc.2016.2.11
The study focuses on the role of silicon in the hot dip galvanizing process. Coating formation and growth were analysed. Centrifugal casting was used to prepare steel substrates with different silicon concentrations (< 0.01%, 0.06%, 0.11%, 0.17%, and 0.30%). Hot dip galvanizing was performed at 450 °C in the industrial galvanizing plant Zincpot (Estonia). The galvanizing time for coating formation was 4–25 s and for coating growth 195 and 1200 s after a longer incubation time. The thickness of the coating was measured and the microstructure of the Zn–Fe coating was examined. Even a very short time contact (4 s) between steel and zinc led to the formation of Fe–Zn intermetallics. The first phase was the ζ phase, immediately followed by the δ and then, after incubation the Γ phase. The reactions that took place in the galvanizing process during the shorter dipping times (< 25 s) were not influenced by silicon concentrations, but the influence of silicon was remarkable after longer dipping times (> 25 s). A schematic model of zinc coating formation is presented. Silicon affects hot dip galvanizing reactions by influencing Zn diffusion into steel and Fe diffusion into the coating.
1. Nai-Yong Tang. Control of silicon reactivity in general galvanizing. Journal of Phase Equilibria and Diffusion, 2008, 29(4), 337–344.
2. Che, C., Lu, J., Kong, G., and Xu, Q. Role of silicon in steels on galvanized coatings. Acta Metall. Sin. (Engl. Lett.), 2009, 22(2), 138–145.
3. Che, C., Lu, J., and Kong, G. Interpretation of Sebisty effect of hot dip galvanized steels. Trans. Nonferrous Met. Soc. China, 2005, 15(6), 1275–1279.
4. Jalel Ben nasr, Snoussi, A., Bradai, C., and Halouani, F. Optimization of hot-dip galvanizing process of reactive steels: minimizing zinc consumption without alloy additions. Mater. Lett., 2008, 62, 3328–3330.
5. Pistofidis, N., Vourlias, G., Konidaris, S., Pavlidou, El., and Stergioudis, G. The combined effect of nickel and bismuth on the structure of hot-dip zinc coatings. Mater. Lett., 2007, 61, 2007–2010.
6. Maass, P. and Peissker, P. (eds). Handbook of Hot-Dip Galvanization. Wiley-VCH Verlag, Weinheim, 2011.
7. Kopyciński, D. The shaping of zinc coating on surface steels and ductile iron casting. Arch. Foundry Eng., 2010, 10, 463–468.
8. Mandal, K. K., Mandal, D., Das, S. K., Balasubramaniam, R., and Mehrotra, S. P. Microstructural study of galvanized coatings formed in pure as well as commercial grade zinc baths. T. Indian I. Metals, 2009, 62(1), 35–40.
9. Uchiyama, Y., Koga, H., and Inokuchi, H. Reaction between Fe–Si alloys and liquid zinc. T. Jpn. I. Met., 1983, 24(5), 272–280.
10. Liberski, P., Tatarek, A., and Mendala, J. Investigation of the initial stage of hot dip zinc coatings on iron alloys with various silicon contents. Solid State Phenom., 2013, 212, 121–126.
11. Foct, J., Reumont, G., Dupont, G., and Perrot, P. How does silicon lead the kinetics of the galvanizing reaction to lose its solid–solid character. J. Phys. IV, 1993, 3, 961–966.
12. Liberski, P., Tatarek, A., Kania, H., and Podolski, P. Coating growth on silicon-containing iron alloys in hot dip galvanizing process. In Proceedings 22nd International Galvanizing Conference INTERGALVA. Madrid, 2009, 181–187.
13. Lu, J., Che, C., Kong, G., Xu, Q., and Chen, J. Influence of silicon on the α-Fe/Γ interface of hot-dip galvanized steels. Surf. Coat. Tech., 2006, 200, 5277–5281.
14. Guttmann, M. Diffusive phase transformations in hot dip galvanizing. Mater. Sci. Forum, 1994, 155–156, 527–548.
15. Xu, J., Bright, M. A., Liu, X., and Barbero, E. Liquid metal corrosion of 316L stainless steel, 410 stainless steel, and 1015 carbon steel in a molten zinc bath. Metall. Mater. Trans. A, 2007, 38(11), 2727–2736.
16. Porter, F. C. Zinc Handbook: Properties, Processing, and Use in Design. CRC Press, 1991.17. Schulz, W.-D., Schubert, P., and Thiele, M. An alternative approach to explaining the effect of silicon on the galvanizing reaction. In Edited Proceedings – Twentieth International Galvanizing Conference. Amsterdam, 2003, 61–64.
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