Hot Dip Pure Zinc Galvanized and Iron-Zinc Galvannealed Coated Steel Sheets For External Car Body Panels

The aim of this paper is to compare how hot-dip pure zinc galvanized and iron-zinc galvannealed coated steel sheets can fit the car industry requirements and to illustrate the metallurgical features responsible for their particular behaviors. Metallurgical routings for the elaboration of these coatings are first compared and their differences in microstructure are pointed out. Relationships between their microstructures and their behaviors at the customer plant during press-forming, welding, phosphating and ED-painting are discussed and compared. End users properties like paint appearance, paint adhesion and corrosion resistance are also compared and related to the coating microstructures.