HIGH STRENGTH STEEL PLATE FOR STRUCTURE WITH A GOOD SEAWATER CORROSION RESISTIVE PROPERTY AND METHOD OF MANUFACTURING THEREOF

摘要

The present invention is by weight, C: 0.03% or more and less than 0.1%, Si: 0.1% or more and less than 0.8%, Mn: 0.3% or more and less than 1.5%, Cr: 0.5% or more and less than 1.5%, Cu: 0.1% or more and 0.5% Less than, Al: 0.01% or more and less than 0.08%, Ti: 0.01% or more and less than 0.1%, Ni: 0.05% or more and less than 0.1%, Nb: 0.002% or more and less than 0.07%, P: 0.03% or less, S: 0.02% or less, High-strength structure containing residual Fe and unavoidable impurities, microstructure, area fraction, bainite 20% or more, polygonal ferrite and acicular ferrite in total less than 80%, pearlite and MA as other phases less than 10% Provided is a molten steel and its manufacturing method.