The paper presents the results of investigations of the growth of protective coating on the surface of ductile iron casting during the hot-dip galvanizing treatment. Ductile iron of the EN-GJS-600-3 grade was melted and two moulds made by different technologies were poured to obtain castings with different surface roughness parameters. After the determination of surface roughness, the hot-dip galvanizing treatment was carried out. Based on the results of investigations, the effect of casting surface roughness on the kinetics of the zinc coating growth was evaluated. It was found that surface roughness exerts an important effect on the thickness of produced zinc coating.
 Maaß. P.. Peißker. P. (1998). Hot-dip galvanizing. Agencja Wydawnicza Placet. Warszawa. (in Polish).
 Nakonieczny. A.. Rafalski. L.. Królikowska. A.. Heidrich. K.. Zasada. J. & Lubawa-Wieleżyński. W. (2011). Protection against corrosion. Konstrukcje stalowe. 1. 22-23. (in Polish).
 Kopyciński. D. & Guzik. E. (2008). The zinc coating on the surface of ductile cast iron. Inżynieria materiałowa. 6. 780-783. (in Polish).
 Szczęsny. A.. Siekaniec. D.. Madizhanowa. A.. & Kopyciński. D. (2013). Features of the zinc coating layer formed on a surface of articles of Fe-C. Archives of Foundry Engineering. 13. 157-160. (in Polish).
 Kopyciński. D. & Guzik. E. (2010). Protection against corrosion of cast iron. Ochrona przed korozją. 3. 106-109. (in Polish).
 Liberski. P.. Kania. H.. Podolski. P.. Tatarek. A. & Mendala. J. (2006). The role of the outer layer of the zinc coating in protecting from corrosion iron alloy. Ochrona przed korozją. 4. 132-135. (in Polish).
 Liberski. P. (3013). Anticorrosion coating immersion. Wydawnictwo Politechniki Śląskiej. Gliwice.
 Liberski. P.. Gierek. A.. Kania. H. & Podolski. P. (2002). Mendala J.. Pucka A.. Galvanizing high carbon ferro alloys. Inżynieria Materiałowa. 5. 430-433. (in Polish).
 Raghavan. V. (2003). Section II: Phase Diagram Evaluations. Journal of Phase Diagram Equilibria. 6. 544-545.
 Kopyciński. D. (2013). Crystallization of intermetallic phases Fe-Zn during hot-dip galvanizing process. TMS 2013 Annual Meeting. 439 - 446.
 Marder. A.R. (2000). The metallurgy of zinc-coated steel. Progress in Material Science. 45. 191-271.