Abstract: A high strength ductile steel sheet for extra deep drawing mainly used for interior or exterior plates of automobile bodies, and a method for manufacturing the same are disclosed. The steel sheet comprises, by weight %, C: 0.010% or less, Si: 0.1% or less, Mn: 0.06˜1.5%, P: 0.15% or less, S: 0.020% or less, Sol. Al: 0.10˜0.40%, N: 0.010% or less, Ti: 0.003˜0.010%, Nb: 0.003˜0.040%, B: 0.0002˜0.0020%, Mo: 0.05% or less, one or both of Sb: 0.005˜0.05% and Sn: 0.005˜0.05%, a total amount of Sb and Sn being in the range of 0.005˜0.1% when both of Sb and Sn are added to the steel sheet, and the balance of Fe and other unavoidable impurities. The steel sheet has surface agglomerates having an average diameter of 1 ?m or less, and a tensile strength of 28˜50 kgf/mm2.

Abstract: A high-ductility, high-strength and high Mn steel strip used for steel strips of automobiles requiring superior formability and high strength, a plated steel strip produced by using the same, and a manufacturing method thereof are disclosed. The high Mn steel strip comprises, by weight %, 0.2˜1.5% of C, 10˜25% of Mn, 0.01˜3.0% of Al, 0.005˜2.0% of Si, 0.03% or less of P, 0.03% or less of S, 0.040% or less of N, and the balance of Fe and other unavoidable impurities. The high-ductility, high-strength and high Mn steel strip, and the plated steel strip produced by using the same have superior surface properties and plating characteristics.

Abstract: There are provided a high-workability high strength steel sheet with excellent workability due to the high elongation and excellent crashworthiness due to the high yield strength, and a method for manufacturing of it. The high manganese steel sheet includes, by weight: carbon (C): 0.2 to 1.5%, manganese (Mn): 10 to 25%, aluminum (Al): 0.01 to 3.0%, phosphorus (P) 0.03% or less, sulfur (S): 0.03% or less, nitrogen (N): 0.040% or less, at least one selected from the group consisting of silicon (Si): 0.02 to 2.5%, titanium (Ti): 0.01 to 0.10% and niobium (Nb): 0.01 to 0.10%, and the balance of Fe and other inevitable impurities. The high manganese steel sheet may be a hot-rolled steel sheet, a cold-rolled steel sheet, or a plated steel sheet, and is suitable for elaborate internal sheets as well as structural members of a car body since it has press workability due to the high elongation and high strain hardening index.

Abstract: A high-manganese hot-dip coated steel sheet is disclosed which provides high corrosion resistance, high ductility and high strength, mainly used for inner and outer panels of automobiles, and a method of manufacturing the same. The high-manganese hot-dip coated steel sheet includes a substrate steel sheet having a composition of (in weight %) 0.1 to 1.5% of C, 5 to 35% of Mn, and the remainder includes Fe and other unavoidable impurities, and a hot-dip zinc coating layer formed on the substrate steel sheet, the hot-dip zinc coating layer having a composition of (in weight %) 0.1 to 10% of Mn, 5 to 15% of Fe, and the remainder including Zn and other unavoidable impurities.

Abstract: A method for manufacturing a steel sheet used for structural members, elements, etc. of automobiles including a front side member, pillar, and the like, and more particularly, a method for manufacturing a steel sheet having a high strength and formability as well as hot-dip galvanizing properties is disclosed. In the method, after an aluminum killed steel slab, which comprises, by weight %,: C: 0.05% to 0.25%; Si: 0.1% to 1.5%; S: 0.02% or less; N: 0.01% or less; Al: 0.02% to 2.0%; Mn: 1.0% to 2.5%; P: 0.001% to 0.1%; Sb: 0.005% to 0.10%; the balance of Fe and other unavoidable impurities, is subjected to a homogenization treatment at a temperature range of 1050° C. to 1300° C., the aluminum killed steel slab is subjected to a hot rolling under a finishing hot rolling temperature of 850° C. to 950° C. and a coiling temperature of 400° C. to 700° C., followed by a cold rolling under a cold rolling reduction ration of 30% to 80%, and annealing the cold rolled steel sheet.