POSCO Holdings Inc.
HEAVY-WALL STEEL PLATE HAVING 450MPA-GRADE TENSILE STRENGTH AND EXCELLENT RESISTANCE TO HYDROGEN INDUCED CRACKING AND METHOD FOR MANUFACTURING SAME

Abstract:

The present disclosure relates to a heavy-wall steel plate having 450 MPa-grade tensile strength and excellent resistance to hydrogen induced cracking, and a method for manufacturing the same. The heavy-wall steel plate includes, by weight, carbon (C): 0.03% to 0.06%, silicon (Si): 0.2% to 0.4%, manganese (Mn): 1.0% to 1.6%, phosphorus (P): 0.03% or less, sulfur (S): 0.003% or less, aluminum (Al): 0.06% or less, nitrogen (N): 0.01% or less, copper (Cu): 0.05% to 0.4%, nickel (Ni): 0.05% to 0.5%, calcium (Ca): 0.0005% to 0.003%, a balance of iron (Fe), and other unavoidable impurities, wherein a thickness of the heavy-wall steel plate is 40 mm or more.