A study of galvanizing reactions of hot-rolled-in scale on a Mn/Si DP steel sheet

Various intermetallic compounds and interfacial precipitates play an important role in the galvanizing reactions for Dual Phase (DP) steels. The interactions between the liquid zinc bath and hot-rolled-in scale on a Mn/Si DP steel surface were investigated. By microstructural analyses, several kinds of Fe, Mn and Si oxides and pure iron were observed at the interface of the simulated galvanized specimens. Furthermore, it was shown that the Fe/Zn alloy was strongly attached to FeO particles from the rolled-in scale, implying that a selective galvanizing reaction took place between the steel and oxide scale. In addition, MnO and SiO 2 particles were also formed at the interface. A significant factor in the galvanizing of these steels has been determined to be the oxidation state of the alloying elements. The reactions taking place at the bath/substrate interface will be discussed.