Effect of Surface Micromorphology and Roughness of Iron Ingot on Microstructures of Hot-Dip Galvanized Coating

Abstract

This study uses ball milling instead of pickling pretreatment to investigate the effect of the surface micromorphology and roughness of the iron ingot on microstructures of the hot-dip galvanized coating. The results show that loose outburst structures form on the protrusions of the substrate surface, and the dense and stable layer forms in the depression. As the surface roughness of the substrate decreases, the thickness of the δ layer in the coating decreases, and the thickness of the ζ layer increases. When the surface roughness Ra is 0.80 μm and 0.56 μm, the ζ crystal grains in the coating are coarse, the ζ layer is loose, and outbursts form in the coating. When Ra\u2009=\u20090.38 μm, the ζ grains in the coating are refined, the thickness of the ζ layer increases sharply, and there is no outburst structure.