A steel plate and a hot-dip galvanized steel plate, superior in terms of high
electromagnetic
shield capacity. The steel plate is prepared from a composition comprising C, N
and S in an amount of 0.150% by weight or less in total; Mn in an amount of 0.1
to 1.0% by weight; Si in an amount of 0.5% by weight or less; Al in an amount of
1.0% by weight or less; P in an amount of 0.06% by weight or less; and Fe for the
remainder, and inevitable elements, and shows a yield strength of 18 kg/mm2 or
higher, and an elongation of 40% or higher. The hot-dip galvanized steel plate
is prepared from a composition comprising C, N and S in an amount of 0.0150 % by
weight or less in total; Mn in an amount of 0.2 to 0.8% by weight; Al in an amount
of 0.6% by weight or less; Si in an amount of 0.4% by weight or less; P in an amount
of 0.06% by weight or less, with the proviso that the sum of Mn, Al, Si and P amounts
to 0.2-1.0% by weight; and Fe for the remainder, and inevitably present elements.
In addition to having high yield strength, the hot-dip galvanized steel plate is
resistant to corrosion owing to the coating of a corrosion-resistant element on
the surface.
