HIGH STRENGTH STEEL PLATE HAVING SUPERIOR ELECTROMAGNETIC SHIELDING PROPERTY

摘要

PURPOSE: A high strength steel plate having superior electromagnetic shielding property of greater than 20 dB based on 1 mm and yield strength of greater than 25 kg/mm¬2. CONSTITUTION: The high strength steel plate comprises 0.012 wt.% or less of C+N; Mn 0.1 to 1.0 wt.%, Si 0.2 to 1.0 wt.%, Si+Al 0.2 to 1.2 wt.%, a balance of Fe and incidental impurities, wherein the steel plate is characterized in that Al content in the steel plate is 0.4 to 1.0 wt.%; a zinc coat is formed on the surface thereof; an organic resin coat is formed on the surface of the zinc coat; a powder including 17 to 99 wt.% of Mg(OH)2 with a specific surface area of greater than 1m¬2/g is coated thereon in the thickness of 15 to 60 micrometers.