POSCO Holdings Inc.
HIGH-STRENGTH AND HIGH-MANGANESE STEEL HAVING EXCELLENT LOW-TEMPERATURE TOUGHNESS AND MANUFACTURING METHOD THEREFOR

Abstract:

An aspect of the present invention relates to a high-strength and high-manganese steel having excellent low-temperature toughness, the high-strength and high-manganese steel comprising, in terms of wt %, 4.3-5.7% of manganese (Mn), 0.015-0.055% of carbon (C), 0.015-0.05% silicon (Si), 0.6-1.7% of aluminum (Al), 0.01-0.1% of niobium (Nb), 0.015-0.055% of titanium (Ti), 0.001-0.005% of boron (B), 0.03% or less of phosphor (P), 0.02% or less of sulfur (S), and the balance iron (Fe) and other inevitable impurities, wherein the microstructure thereof comprises, in terms of percent by volume, 40-60% of martensite and 40-60% of tempered martensite.