Abstract: Provided is an aluminum-based plated steel that is provided for vehicles by hot forming, an aluminum-based alloy plated steel manufactured using the same, and method of manufacturing thereof.

Abstract: Provided is a plated steel sheet for hot press forming, having an excellent impact property, including: a base steel sheet comprising, by wt %, 0.15-0.4% of C, 0.05-1.0% of Si, 0.6-3.0% of Mn, 0.001-0.05% of P, 0.0001-0.02% of S, 0.01-0.1% of Al, 0.001-0.02% of N, 0.001-0.01% of B, 0.01-0.5% of Cr, 0.01-0.05% of Ti, and the balance of Fe and inevitable impurities; and an Al—Si plated layer formed on the surface of the base steel sheet. A thickness of a carbon-depleted layer in a surface layer part of the base steel sheet is 5 ?m or less. The surface layer part means a region from the surface of the base steel sheet to a depth of 200 ?m, and the carbon-depleted layer means a region which the carbon content is 50% or less of an average carbon amount (C0) of the base steel sheet.

Abstract: An Al—Fe alloy coated steel sheet includes a base steel sheet and an alloy coating layer, wherein the base steel sheet includes, by wt %, C: 0.1%˜0.5%, Si: 0.01%˜2%, Mn: 0.01%˜10%, P: 0.001%˜0.05%, S: 0.0001%˜0.02%, Al: 0.001%˜1.0%, N: 0.001%˜0.02%, and the balance of Fe and other impurities, wherein the alloy coating layer includes: an Al—Fe alloy layer I formed on the base steel sheet and having a Vickers hardness of 200˜800 Hv; an Al—Fe alloy layer III formed on the Al—Fe alloy layer I and having a Vickers hardness of 700˜1200 Hv; and an Al—Fe alloy layer II formed in the Al—Fe alloy layer III continuously or discontinuously in a length direction of the steel sheet, and having a Vickers hardness of 400˜900 Hv, wherein an average oxygen content at a depth of 0.1 ?m from a surface of the oxide layer is 20% or less by weight.

Abstract: Provided is a method for manufacturing an HPF part having excellent bending properties including: manufacturing a hot rolled steel sheet; coiling the hot rolled steel sheet within a range of 450° C. to 750° C. for a time satisfying Expression 1; cold rolling, annealing and then hot dip aluminum plating on the annealed steel sheet; heating the hot dip aluminum plated steel sheet to a temperature of 850° C. to 1000° C. and maintaining the hot dip aluminum plated steel sheet for a certain period of time; and hot forming the heated steel and cooling at a temperature within a range of 200° C. or lower at a cooling speed of 20° C./s to 1000° C./s at the same time to manufacture an HPF part, [Expression 1] 190,000?[coiling temperature (CT)×Time (min)]/2?350,000, in the Relational Expression 1, Time refers to a time taken to reach 200° C. from coiling temperature.

Abstract: Provided is a hot press-formed member having excellent crack propagation resistance and ductility. The hot press-formed member includes: a base steel sheet and a zinc or zinc alloy plating layer on at least one surface of the base steel sheet. The base steel sheet contains, by wt %, carbon (C): 0.08-0.30%, silicon (Si): 0.01-2.0%, manganese (Mn): 3.1-8.0%, aluminum (Al): 0.001-0.5%, phosphorus (P): 0.001-0.05%, sulfur (S): 0.0001-0.02%, nitrogen (N): 0.02% or less, and a balance of iron (Fe) and other impurities. The hot press-formed member comprises 1-30 area % of retained austenite as a microstructure, and a Mn(wt %)/Zn(wt %) content ratio in an oxide layer of 0.5-1.2 ?m in a thickness direction from a surface layer of the plating layer is 0.1 or more.

Abstract: The present invention provides: a steel sheet capable of manufacturing a formed product having superior bendability and ultra-high strength when compared with conventional steel sheets for manufacturing a hot press formed product; the formed product having superior bendability and ultra-high strength by using the same; and a method for manufacturing the same.

Abstract: Provided is a method for manufacturing an HPF part having excellent bending properties including: manufacturing a hot rolled steel sheet; coiling the hot rolled steel sheet within a range of 450° C. to 750° C. for a time satisfying Expression 1; cold rolling, annealing and then hot dip aluminum plating on the annealed steel sheet; heating the hot dip aluminum plated steel sheet to a temperature of 850° C. to 1000° C. and maintaining the hot dip aluminum plated steel sheet for a certain period of time; and hot forming the heated steel and cooling at a temperature within a range of 200° C. or lower at a cooling speed of 20° C./s to 1000° C./s at the same time to manufacture an HPF part, [Expression 1] 190,000?[coiling temperature (CT)×Time (min)]/2?350,000, in the Relational Expression 1, Time refers to a time taken to reach 200° C. from coiling temperature.

Abstract: An Al—Fe alloy coated steel sheet includes a base steel sheet and an alloy coating layer, wherein the base steel sheet includes, by wt %, C: 0.1%˜0.5%, Si: 0.01%˜2%, Mn: 0.01%˜10%, P: 0.001%˜0.05%, S: 0.0001%˜0.02%, Al: 0.001%˜1.0%, N: 0.001%˜0.02%, and the balance of Fe and other impurities, wherein the alloy coating layer includes: an Al—Fe alloy layer I formed on the base steel sheet and having a Vickers hardness of 200˜800 Hv; an Al—Fe alloy layer III formed on the Al—Fe alloy layer I and having a Vickers hardness of 700˜1200 Hv; and an Al—Fe alloy layer II formed in the Al—Fe alloy layer III continuously or discontinuously in a length direction of the steel sheet, and having a Vickers hardness of 400˜900 Hv, wherein an average oxygen content at a depth of 0.1 ?m from a surface of the oxide layer is 20% or less by weight.

Abstract: Provided is an HPF member having excellent bending characteristics and a hot-dip aluminum plated layer formed on a surface of a base steel sheet. The base steel sheet includes, in terms of wt %, 0.18-0.25% of C, 0.1-0.5% of Si, 0.9-1.5% of Mn, 0.03% or less of P, 0.01% or less of S, 0.01-0.05% of Al, 0.05-0.5% of Cr, 0.01-0.05% of Ti, 0.001-0.005% of B, 0.009% or less of N, the balance Fe and other impurities; a ferrite phase having a thickness within 50 ?m is continuously or discontinuously formed inside a surface portion of the base steel sheet; the fraction of the surface portion occupied by the ferrite phase is 5% or less; and carbide materials having a size of 1 ?m or less are scattered and distributed in the surface portion of the base steel sheet so as to occupy 90% or more of the overall carbide distribution.

Abstract: Provided is a method of manufacturing a zinc-plated steel sheet. The method includes: coating a metal on the steel sheet on a steel sheet; annealing the metal coated steel sheet; and zinc plating the annealed steel sheet by dipping in a molten zinc plating bath. Further provided is a method of manufacturing a hot-press part including: coating a metal on the steel sheet on a steel sheet; annealing the metal coated steel sheet; zinc plating the annealed steel sheet by dipping in a molten zinc plating bath; heating the zinc-plated steel sheet; and press forming the heated steel sheet.

Abstract: Provided is a zinc-plated steel sheet for hot pressing having outstanding surface characteristics, comprising: a steel foundation plate comprising a metal surface diffusion layer of which the Gibbs free energy reduction per mole of oxygen during oxidation is less than that of Cr, an aluminum-rich layer containing at least 30 wt. % of aluminum formed on the surface diffusion layer, and a zinc plating layer formed on the aluminum-rich layer. In this way, a metal having a low affinity for oxygen is coated to an effective thickness prior to annealing and thus the creation of annealing oxides at the surface of the steel sheet is suppressed and a uniform zinc plating layer is formed, and alloying of the zinc plating layer is promoted during press-processing heat treatment. Cracking in the steel foundation plate during hot press molding is prevented.

Abstract: Provided is a warm-pressed member comprising, by weight %, C: 0.01% to 0.5%, Si: 3.0% or less (excluding 0%), Mn: 3% to 15%, P: 0.0001% to 0.1%, S: 0.0001% to 0.03%, Al: 3.0% or less (excluding 0%), N: 0.03% or less (excluding 0%), and the balance of Fe and inevitable impurities. After a warm press forming process and a cooling process, the warm-pressed member has a microstructure comprising: 5 volume % to 50 volume % of retained austenite; and at least one of ferrite, martensite, tempered martensite, and bainite as a remainder.

Abstract: Provided is an HPF member having excellent bending characteristics and a hot-dip aluminum plated layer formed on a surface of a base steel sheet. The base steel sheet includes, in terms of wt %, 0.18-0.25% of C, 0.1-0.5% of Si, 0.9-1.5% of Mn, 0.03% or less of P, 0.01% or less of S, 0.01-0.05% of Al, 0.05-0.5% of Cr, 0.01-0.05% of Ti, 0.001-0.005% of B, 0.009% or less of N, the balance Fe and other impurities; a ferrite phase having a thickness within 50 ?m is continuously or discontinuously formed inside a surface portion of the base steel sheet; the fraction of the surface portion occupied by the ferrite phase is 5% or less; and carbide materials having a size of 1 ?m or less are scattered and distributed in the surface portion of the base steel sheet so as to occupy 90% or more of the overall carbide distribution.

Abstract: The present invention provides: a steel sheet capable of manufacturing a formed product having superior bendability and ultra-high strength when compared with conventional steel sheets for manufacturing a hot press formed product; the formed product having superior bendability and ultra-high strength by using the same; and a method for manufacturing the same.

Abstract: A steel sheet for forming having low-temperature heat treatment property, in which heat treatment is performed within a range of lower temperature than a conventional steel sheet in the event of hot press forming or post-heat treatment after cold forming, a method of manufacturing the same, and a method of manufacturing parts using the same. The steel sheet has a composition of, by weight, carbon (C): 0.15 to 0.35%, silicon (Si): 0.5% or less, manganese (Mn): 1.5 to 2.2%, phosphorus (P): 0.025% or less, sulfur (S): 0.01% or less, aluminum (Al): 0.01 to 0.05%, nitrogen (N): 50 to 200 ppm, titanium (Ti): 0.005 to 0.05%, tungsten (W): 0.005 to 0.1%, and boron (B): 1 to 50 ppm, wherein Ti/N: less than 3.4, where Ti/N is the atomic ratio of the corresponding elements, Ceq expressed by the following formula ranges from 0.48 to 0.58, and temperature Ar3 ranges from 670° C. to 725° C. Wherein Ceq C+Si/24+Mn/6+Ni/40+Cr/5+V/14 where C, Si, Mn, Ni, Cr and V indicate the contents (wt %) of the respective elements.

Abstract: Provided is a zinc-plated steel sheet for hot pressing having outstanding surface characteristics, comprising: a steel foundation plate comprising a metal surface diffusion layer of which the Gibbs free energy reduction per mole of oxygen during oxidation is less than that of Cr, an aluminium-rich layer containing at least 30 wt. % of aluminium formed on the surface diffusion layer, and a zinc plating layer formed on the aluminium-rich layer. In this way, a metal having a low affinity for oxygen is coated to an effective thickness prior to annealing and thus the creation of annealing oxides at the surface of the steel sheet is suppressed and a uniform zinc plating layer is formed, and alloying of the zinc plating layer is promoted during press-processing heat treatment. Cracking in the steel foundation plate during hot press molding is prevented.

Abstract: Provided is a zinc-plated steel sheet for hot pressing having outstanding surface characteristics, comprising: a steel foundation plate comprising a metal surface diffusion layer of which the Gibbs free energy reduction per mole of oxygen during oxidation is less than that of Cr; an aluminum-rich layer containing at least 30 wt. % of aluminum formed on the surface diffusion layer, and a zinc plating layer formed on the aluminum-rich layer. In this way, a metal having a low affinity for oxygen is coated to an effective thickness prior to annealing and thus the creation of annealing oxides at the surface of the steel sheet is suppressed and a uniform zinc plating layer is formed, and alloying of the zinc plating layer is promoted during press-processing heat treatment. Cracking in the steel foundation plate during hot press molding is prevented.

Abstract: Provided are a steel sheet for warm press forming that can have high strength, good elongation, and thus improved crashworthiness after being warm pressed, and a warm-pressed member formed of the steel sheet, and manufacturing methods thereof. The steel sheet for warm press forming includes, by weight %, C: 0.01% to 0.5%, Si: 3.0% or less (excluding 0%), Mn: 3% to 15%, P: 0.0001% to 0.1%, S: 0.0001% to 0.03%, Al: 3.0% or less (excluding 0%), N: 0.03% or less (excluding 0%), and the balance of Fe and inevitable impurities.

Abstract: The present invention relates to a hot press forming steel plate made of a composition comprising: 0.3-1.0 wt % of C; 0.0-4.0 wt % of Mn; 1.0-2.0 wt % of Si; 0.01-2.0 wt % of Al; 0.015 wt % or less of S; 0.01 wt % or less of N; and the remainder being Fe and unavoidable impurities. Further, the present. invention relates to a method for manufacturing the hot press forming steel plate, characterized by comprising the steps of: heating, to between 1100 and 1300° C., a steel slab having the composition; performing hot rolling finishing between. an Ar3 transformation point and 950° C.; and performing winding between MS and 720° C. Further, the present invention. relates to a hot press formed member characterized by having the composition, and having a dual phase microstructure made of bainite and residual austenite.

Abstract: Provided is a steel sheet for a formed member having enhanced ductility, a formed member, and a method for manufacturing the formed member, and more particularly, to a steel sheet for making a formed member having high strength and ductility such as an automotive structural member and a reinforcing member, a formed member, and a method for manufacturing the formed member. The steel sheet for a formed member has enhanced ductility, and includes, by weight %, C: 0.1% to 1.0%, Si+Al: 0.4% to 3.0%, Mn: 0.1% to 5.0%, P: 0.0001% to 0.1%, S: 0.0001% to 0.03%, N: 0.03% or less (but not 0%), and the balance of Fe and inevitable impurities. The formed member having high strength and ductility that can be used for forming an automotive structural member, a reinforcing member, etc. In addition, the formed member can be used for a heat-treatable impact resistant member.