18961786. ULTRA-HIGH STRENGTH COLD-ROLLED STEEL SHEET AND MANUFACTURING METHOD THEREFOR (Hyundai Steel Company)
ULTRA-HIGH STRENGTH COLD-ROLLED STEEL SHEET AND MANUFACTURING METHOD THEREFOR
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ULTRA-HIGH STRENGTH COLD-ROLLED STEEL SHEET AND MANUFACTURING METHOD THEREFOR
This abstract first appeared for US patent application 18961786 titled 'ULTRA-HIGH STRENGTH COLD-ROLLED STEEL SHEET AND MANUFACTURING METHOD THEREFOR
Original Abstract Submitted
Provided are an ultra-high strength cold-rolled steel sheet whose microstructure has been controlled to have high strength and elongation, and a manufacturing method thereof. In accordance with an embodiment of the present disclosure, the ultra-high strength cold-rolled steel sheet includes: carbon (C): 0.28% to 0.45%; silicon (Si): 1.0% to 2.5%; manganese (Mn): 1.5% to 3.0%; aluminum (Al): 0.01% to 0.05%; chromium (Cr): greater than 0% and 1.0% or less; molybdenum (Mo): greater than 0% and 0.5% or less; a total of niobium (Nb), titanium (Ti) and vanadium (V): greater than 0% and 0.1% or less; phosphorus (P): greater than 0% and 0.03% or less; sulfur (S): greater than 0% and 0.03% or less; and nitrogen (N): greater than 0% and 0.01% or less, based on % by weight; and the remainder being Fe and other unavoidable impurities, wherein the ultra-high strength cold-rolled steel sheet satisfies a yield strength (YP) of 1180 MPa or more, a tensile strength (TS) of 1470 MPa or more, an elongation (El) of 15% or more, a yield ratio (YR) of 75% or more, and a bendability (R/t) of 3.0 or less.