POSCO Holdings Inc.
HIGH STRENGTH STEEL PLATE FOR STRUCTURE WITH GOOD SEAWATER CORROSION RESISTANT PROPERTY AND METHOD OF MANUFACTURING SAME

Abstract:

The present invention provides a high strength steel plate for a structure and a method of manufacturing same, wherein the high strength steel plate fora structure comprises, by weight %, 0.03% (inclusive) to 0.1% (exclusive) of C, 0.1% (inclusive) to 0.8% (exclusive) of Si, 0.3% (inclusive) to 1.5% (exclusive) of Mn, 0.5% (inclusive) to 1.5% (exclusive) of Cr, 0.1% (inclusive) to 0.5% (exclusive) of Cu, 0.01% (inclusive) to 0.08% (exclusive) of Al, 0.01% (inclusive) to 0.1% (exclusive) of Ti, 0.05% (inclusive) to 0.1% (exclusive) of Ni, 0.002% (inclusive) to 0.07% (exclusive) of Nb, 0.03% or less of P, 0.02% or less of S, and the balance of Fe and unavoidable impurities, and has a microstructure comprising, by area fraction, 20% or more of bainite, less than 80% of polygonal ferrite and acicular ferrite in total, and less than 10% of pearlite and MA as the other phases.