POSCO Holdings Inc.
LOW-TEMPERATURE STEEL PLATE HAVING EXCELLENT IMPACT TOUGHNESS, AND METHOD FOR MANUFACTURING SAME

Abstract:

Provided are a low-temperature steel plate having excellent impact toughness, and a method for manufacturing same, the low-temperature steel plate comprising, in wt %, 0.02-0.08% C, 6.0-7.5% 0.5-0.9% Mn, 0.03-0.15% Si, 0.02-0.3% Mo, and 0.1-0.3% Cr, and 50 ppm or less of P, 10 ppm or less of 5, and the remainder in Fe and various unavoidable impurities, and the microstructure at 1/4t (t: thickness of the steel plate) location of the steel plate comprising, in % surface area, 10-35% tempered bainite, 3-15% residual austenite, and the remainder in tempered martensite, and having granularity of 10 or less of high angle grain boundaries at 15.degree. or greater as measured by EBSD.