ESTONIAN ACADEMY
PUBLISHERS
eesti teaduste
akadeemia kirjastus
PUBLISHED
SINCE 1952
 
Proceeding cover
proceedings
of the estonian academy of sciences
ISSN 1736-7530 (Electronic)
ISSN 1736-6046 (Print)
Impact Factor (2020): 1.045

The role of silicon in the hot dip galvanizing process; pp. 159–165

Full article in PDF format | doi: 10.3176/proc.2016.2.11

Authors
Sirli Sepper, Priidu Peetsalu, Priit Kulu, Mart Saarna, Valdek Mikli

Abstract

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.


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