Influences of Cu in Steel on the Formation of Alloy Layer in Hot-dip Galvanizing

Abstract

The influence of Cu in steel on hot-dip galvanizing of hot rolled steel was studied. We investigated the formation of the alloy layer formed at the overlay-substrate interface. On Cu-Ti-added steel, the formation of δ₁ phase was promoted, while Fe₂Al₅ was the main phase on the usual Ti-added steel. We concluded that this phenomenon was caused by the dissolution of Cu into the Zn bath that had deposited on the surface during pickling, and suggested that the dissolution of Cu should decrease the activity of Al and make Fe₂Al₅ less stable than that of Ti-added steel, which caused the easy precipitation of δ₁.