Galvanized galvanized original plate and manufacturing method thereof and alloyed hot-dip galvanized steel plate

摘要

A galvanized steel sheet having good surface properties is provided by proposing a method of suppressing the occurrence of patterned surface defects. 0.005% or less of Si, 0.03% or less of Si, 0.5% or more and 1.0% or less of Mn, 0.005% or more and 0.015% or less of Nb, 0.01% or more and 0.05% or less of Pb, 0.03% or less of S, 0.01% or more of Al 0.08% or less and N: 0.005% or less, the balance being Fe and inevitable impurities, adjusting the strength of Mn in the surface layer of steel sheet by glow discharge emission spectroscopy (GDS) to 3.5 (V) or less .