Abstract: Provided is a high strength steel sheet and a manufacturing method therefor, and, more specifically, to a steel sheet and a manufacturing method therefor, the steel sheet having excellent thermal stability to have high yield ratio and high strength even after heat treatment at a relatively low temperature.

Abstract: The present invention relates to steel used for a sash component and the like of a vehicle and, more specifically, to a hot-rolled steel sheet for a high-strength electric resistance welded steel pipe having excellent expandability and a method for manufacturing same, the hot-rolled steel sheet having a smaller decrease in the strength of a welding heat-affected zone (HAZ) formed during electric resistance welding, in comparison with a base material.

Abstract: Provided is a high-strength steel strip having excellent workability, and a method for manufacturing the same, and more specifically, to: a high-strength steel strip has excellent yield strength and elongation rate due to having a uniform microstructure, and thus does not suffer cracking when worked; and a method for manufacturing same.

Abstract: Provided is an ultra-high-strength steel sheet having excellent thermal stability and a high yield ratio, and ultra-high strength even after heat treatment at a relatively low temperature, and a manufacturing method therefor. The steel sheet includes, by wt %, 0.05 to 0.13% of C, 0.01 to 0.5% of Si, 0.8 to 2.0% of Mn, 0.005 to 1.2% of Cr, 0.001 to 0.5 of Mo, 0.001 to 0.02% of P, 0.001 to 0.01% of S, 0.01 to 0.1% of Al, 0.001 to 0.01% of N, 0.01 to 0.05% of Ti, 0.001 to 0.03% of Nb, 0.001 to 0.2% of V, 0.0003 to 0.003% of B, and a balance of Fe and unavoidable impurities, and a microstructure including, by area %, 60 to 90% of martensite, including tempered martensite, 10 to 40% of bainite, and 5% or less of ferrite.

Abstract: The hot-rolled coated steel sheet comprising: in wt %, C: 0.05-0.14%, Si: 0.1-1.0%, Mn: 1.0-2.0%, P: 0.001-0.05%, S: 0.001-0.01%, AI: 0.01-0.1%, Cr: 0.005-1.0%, Ti: 0.005-0.13%, Nb: 0.005-0.03%, N: 0.001-0.01%, Fe residues, and other inevitable impurities; a mixed structure of ferrite and bainite as a main phase; and as a remaining structure, one or more selected from the group consisting of martensite, austenite, and phase martensite (MA), wherein a fraction of the ferrite and bainite is 95-99 area % and Equation 1 is satisfied. [Equation 1] FCO{110}<112>+FCO{112}<111>?10 where, FCO{110}<112> and FCO{112}<111>, each representing an area fraction occupied by a structure having ac crystal orientation of {110}<112> and {112}<111>.

Abstract: Provided is a steel sheet that can be applied to automobile chassis parts and the like, and more particularly, to a steel sheet having excellent thermal stability while having high strength to have excellent strength and bake hardening ability even after a heat treatment at a relatively low temperature.

Abstract: Provided are a high-strength thick hot-rolled steel sheet having excellent elongation and a method for manufacturing same. The high-strength thick hot-rolled steel sheet comprises, by weight %: 0.05-0.15% of C; 0.01-1.0% of Si; 1.0-2.0% of Mn; 0.01-0.1% of Sol. Al; 0.005-1.0% of Cr; 0.001-0.02% of P; 0.001-0.01% of S; 0.001-0.01% of N; 0.005-0.07% of Nb; 0.005-0.11% of Ti; and the remainder of Fe and unavoidable impurities, satisfies relation 1, and has a microstructure comprising, by area %: 25-50% of polygonal ferrite; 30-50% of bainitic ferrite and acicular ferrite; 20% or less of bainite; less than 5% of the sum of area fractions of carbide and pearlite structures having a diameter of 0.5 ?m or more, observed within a unit area (1 cm2); and less than 5% of phase MA (martensitic-austenitic constituents).

Abstract: Provided is a method for manufacturing a steel sheet, the method including: reheating a steel slab at a temperature of 1200° C. to 1350° C., the steel slab including, by weight%, carbon (C): 0.05% to 0.14%, silicon (Si): 0.01% to 1.0%, manganese (Mn): 1.5% to 2.5%, aluminum (Al): 0.01% to 0.1%, chromium (Cr): 0.005% to 1.0%, phosphorus (P): 0.001% to 0.05%, sulfur (S): 0.001% to 0.01%, nitrogen (N): 0.001% to 0.01%, niobium (Nb): 0.005% to 0.06%, titanium (Ti): 0.005% to 0.11%, and a balance of iron (Fe) and inevitable impurities; finish hot rolling the reheated steel slab under predetermined conditions to obtain a hot-rolled steel sheet; cooling the hot-rolled steel sheet at a cooling rate of 10° C./s to 100° C./s to a temperature of 400° C. to 500° C. after the finish hot rolling; and coiling the steel sheet at a temperature of 400° C. to 500° C. after the cooling.

Abstract: The hot-rolled coated steel sheet comprising: in wt %, C: 0.05-0.14%, Si: 0.1-1.0%, Mn: 1.0-2.0%, P: 0.001-0.05%, S: 0.001-0.01%, AI: 0.01-0.1%, Cr: 0.005-1.0%, Ti: 0.005-0.13%, Nb: 0.005-0.03%, N: 0.001-0.01%, Fe residues, and other inevitable impurities; a mixed structure of ferrite and bainite as a main phase; and as a remaining structure, one or more selected from the group consisting of martensite, austenite, and phase martensite (MA), wherein a fraction of the ferrite and bainite is 95-99 area % and Equation 1 is satisfied. [Equation 1] FCO{110}<112>+FCO{112}<111>?10 where, FCO{110}<112> and FCO{112}<111>, each representing an area fraction occupied by a structure having ac crystal orientation of {110}<112> and {112}<111>.

Abstract: The present invention relates to steel used for a sash component and the like of a vehicle and, more specifically, to a hot-rolled steel sheet for a high-strength electric resistance welded steel pipe having excellent expandability and a method for manufacturing same, the hot-rolled steel sheet having a smaller decrease in the strength of a welding heat-affected zone (HAZ) formed during electric resistance welding, in comparison with a base material.

Abstract: A hot-rolled coated steel sheet including: in wt %, C: 0.05-0.14%, Si: 0.1-1.0%, Mn: 1.0-2.0%, P: 0.001-0.05%, S: 0.001-0.01%, AI: 0.01-0.1%, Cr: 0.005-1.0%, Ti: 0.005-0.13%, Nb: 0.005-0.03%, N: 0.001-0.01%, Fe residues, and other inevitable impurities; a mixed structure of ferrite and bainite as a main phase; and as a remaining structure, one or more selected from the group consisting of martensite, austenite, and phase martensite (MA), wherein a fraction of the ferrite and bainite is 95-99 area % and Equation 1 is satisfied. [Equation 1] FCO{110}<112>+FCO{112}<111>?10 where, FCO{110}<112> and FCO{112}<111>, each representing an area fraction occupied by a structure having ac crystal orientation of {110}<112> and {112}<111>.

Abstract: Provided is a high-strength steel sheet having high impact resistance. The steel sheet includes: by weight %, carbon (C): 0.05% to 0.14%, silicon (Si): 0.01% to 1.0%, manganese (Mn): 1.5% to 2.5%, aluminum (Al): 0.01% to 0.1%, chromium (Cr): 0.005% to 1.0%, phosphorus (P): 0.001% to 0.05%, sulfur (S): 0.001% to 0.01%, nitrogen (N): 0.001% to 0.01%, niobium (Nb): 0.005% to 0.06%, titanium (Ti): 0.005% to 0.11%, and the balance of iron (Fe) and inevitable impurities. The steel sheet has a microstructure comprising ferrite and bainite in a total area fraction of 90% or more. The steel sheet has a value of 0.05 to 1.0 as a shear texture ({110}<112>, {112}<111>) area ratio of a center region (ranging deeper than 1/10t to ½t in a thickness direction, t refers to thickness (mm)) and a surface region (ranging from a surface to 1/10t in the thickness direction).

Abstract: The present invention relates to steel used for a sash component and the like of a vehicle and, more specifically, to a hot-rolled steel sheet for a high-strength electric resistance welded steel pipe having excellent expandability and a method for manufacturing same, the hot-rolled steel sheet having a smaller decrease in the strength of a welding heat-affected zone (HAZ) formed during electric resistance welding, in comparison with a base material.

Abstract: The present invention relates to steel used for a sash component and the like of a vehicle and, more specifically, to a hot-rolled steel sheet having excellent durability and a method for manufacturing same, the hot-rolled steel sheet having no cracks formed on a material and a welding heat-affected zone (HAZ) even after pipemaking and molding due to a smaller decrease in the strength of the welding heat-affected zone formed during electric resistance welding in comparison with the strength of the material (base material).

Abstract: Provided is a steel used for chassis parts, etc. of an automobile and, more specifically, to a hot rolled steel plate for an electric resistance welded steel pipe, which shows an excellent weldability in electric resistance welding, and a manufacturing method thereof.

Abstract: Provided are thick hot-rolled composite-phase steel having excellent durability and a manufacturing method therefor. The thick composite-phase steel having excellent durability according to the present invention comprises, by wt %, C: 0.05 to 0.15%, Si: 0.01 to 1.0%, Mn: 1.0 to 2.3%, Al: 0.01 to 0.1%, Cr: 0.005 to 1.0%, P: 0.001 to 0.05%, S: 0.001 to 0.01%, N: 0.001 to 0.01%, Nb: 0.005 to 0.07%, Ti: 0.005 to 0.11%, Fe, and inevitable impurities, and has a mixed phase of ferrite and bainite as a base structure, wherein, in the base structure, the area fraction of each of a pearlite phase and a martensite and austenite (MA) phase is less than 5%, and the area fraction of a martensite phase is less than 10%.

Abstract: Thick high-strength steel having a high yield ratio and excellent durability, and a method for manufacturing same are provided. The thick high-strength steel having a high yield ratio and excellent durability of the present invention comprises, in percentage by weight, C: 0.05 to 0.15%, Si: 0.01 to 1.0%, Mn: 1.0 to 2.3%, Al: 0.01 to 0.1%, Cr: 0.005 to 1.0%, P: 0.001 to 0.05%, S: 0.001 to 0.01%, N: 0.001 to 0.01%, Nb: 0.005 to 0.07%, Ti 0.005 to 0.11%, Fe and unavoidable impurities.

Abstract: Provided is a high-strength steel sheet having excellent burring workability in a low temperature range, which is mainly used for automobile chassis parts such as members, lower arms, wheel disks, etc.; and a manufacturing method therefor.

Abstract: Provided is a steel material that may be used for arms, frames, beams, brackets, reinforcing materials, etc. of chassis parts of a vehicle and, more specifically, to a high strength hot-rolled steel sheet having excellent workability and a method for manufacturing same. The steel sheet includes: by weight %, 0.1-0.15% of C, 2.0-3.0% of Si, 0.8-1.5% of Mn, 0.001-0.05% of P, 0.001-0.01% of S, 0.01-0.1% of Al, 0.7-1.7% of Cr, 0.0001-0.2% of Mo, 0.02-0.1% of Ti, 0.01-0.03% of Nb, 0.001-0.005% of B, 0.1-0.3% of V, 0.001-0.01% of N, and a balance of Fe and inevitable impurities, wherein tensile strength (TS) is 1180 MPa or more, a product (TS×E1) of tensile strength and elongation is 20,000 MPa % or more, and a product (TS×HER) of tensile strength and hole expandability is 30,000 MPa % or more.

Abstract: The present invention relates to steel used for members of chassis parts and wheel discs of commercial vehicles, or the like and, more specifically, to a high-strength steel with excellent durability and a method for manufacturing same.