Posco Co., Ltd

Posco

Chang-Sik Choi

Sang-Ho Han

Tae-Jin Song

Jeong-Eun Kim

Sung-Il Kim

Yon-Kyun Song

Young-Ha Kim

Kwang-Tai Min

Kwang-Keun Chin

Provided are a hot rolled steel sheet having excellent crashworthiness and a method for manufacturing same. The hot rolled steel sheet of the present invention contains, in weight %, 0.05-0.13% of carbon (C), 0.2-2.0% of silicon (Si), 1.3-3.0% of manganese (Mn), 0.01-0.1% of aluminum (Al), 0.001-0.05% of phosphor (P), 0.001-0.05% of sulfur (S), 0.001-0.02% of nitrogen (N), and the balance being Fe and other inevitable impurities, and has a steel microstructure comprising, in area %, 55% or more of bainitic ferrite, 10% or more of a martensite/austenite composite phase (MA), the sum of the bainitic ferrite and the martensite/austenite composite phase (MA) being 95% or more, and the remaining total being less than 5% of granular ferrite, retained austenite, and carbides.

Hot rolled steel sheet having excellent crashworthiness and method for manufacturing same

Provided is a method of manufacturing a hot rolled steel sheet having excellent formability and fatigue properties, including: preparing a slab including, by weight %, 0.3 to 0.8% of carbon C, 13 to 25% of manganese (Mn), 0.1 to 1.0% of vanadium (V), 0.005 to 2.0% of silicon (Si), 0.01 to 2.5% of aluminum (Al), 0.03% or less of phosphorus (P), 0.03% or less of sulfur (S), 0.04% or less (excluding 0%) of nitrogen (N), and a remainder of iron (Fe) and inevitable impurities; heating the slab to 1050 to 1250° C.; finish rolling, the slab heated in the heating, at a temperature of not lower than a recrystallization temperature of a region having an average V concentration and not higher than a recrystallization temperature of a region having twice the average V concentration, to obtain a hot rolled steel sheet; and coiling the hot-rolled steel sheet at 50 to 700° C.

Hot rolled steel sheet having excellent formability and fatigue properties and manufacturing method therefor

Provided is a hot rolled steel sheet having excellent formability and fatigue properties comprising, in percentage by weight: 0.3-0.8% of C; 13-25% of Mn; 0.1-1.0% of V; 0.005-2.0% of Si; 0.01-2.5% of Al; 0.03% or less of P; 0.03% or less of S; 0.04% or less (excluding 0%) of N; and the balance being Fe and inevitable impurities, wherein, when viewed in a cross section in the thickness direction, the hot rolled steel sheet comprises, by area fraction, 20-70% of a non-recrystallized structure and 30-80% of a recrystallized structure.

Provided are a high manganese hot dip aluminum-plated steel sheet and a method for manufacturing the same, the steel sheet including: a base steel comprising, by wt %, 0.3-0.9% of C, 10-25% of Mn, 0.01-0.5% of Ti, 0.01-0.2% of Sn, 0.01-0.1% of Sb, and the balance of Fe and inevitable impurities; a hot dip aluminum-based steel plated layer formed on the base steel sheet and comprising 0.1 wt % or more of a sum of one or more types among Li, Na, and K, and the balance of Al and inevitable impurities; and an Al&#x2014;Fe&#x2014;Si&#x2014;Mn based alloy layer formed between the base steel sheet and the aluminum-based plated layer, and having a dual structure with different average Fe amounts.

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Gwangyang-si, South Korea

Chang-Sik Choi