Chromated electro-galvanized steel sheet excellent in corrosion resistance and process for manufacturing same

摘要

A chromated electro-galvanized steel sheet is manufactured by electro-galvanizing a steel sheet in an acidic galvanizing bath containing zinc with or without specified amounts of cobalt, or with specified amounts of cobalt and with at least one of chromium (Cr+3, Cr+6 or Cr+3 and Cr+6) and zirconium; then electro-galvanizing in a zinc-based galvanizing bath containing specified amounts of at least one of chromium (Cr+3, Cr+6 or Cr+3 and Cr+6), tin and indium; and chromating the resulting steel sheet.