A hot pressed member disclosed herein includes: a base steel sheet; a Fe—Zn—Al—Mg-based alloy coated layer containing an α-Fe phase and a Γ phase and formed on at least one surface of the base steel sheet; and an oxide layer containing Zn, Al, and Mg and formed on the Fe—Zn—Al—Mg-based alloy coated layer, in which a ratio of I.sub.Γ/I.sub.α is 0.5 or less when measured by X-ray diffraction using a Co-Kα (wavelength: 1.79021 Å) radiation source at an incident angle of 25°, where IF is an intensity of a diffraction peak of (411) plane of the Γ phase present in an angular range of 41.5°≤2θ≤43.0° and I.sub.α is an intensity of a diffraction peak of (110) plane of the α-Fe phase present in an angular range of 51.0°≤2θ≤52.0°, and a sum of Al and Mg concentrations in the oxide layer is 28 atomic % or more.

The invention relates to a method for coating a steel sheet or steel strip to which an aluminium-based coating is applied in a dip-coating process and the surface of the coating is freed of a naturally occurring aluminium oxide layer. In order to provide a low-cost method for coating steel sheets or steel strips that makes the steel sheets or steel strips outstandingly suitable for the production of components by means of press hardening and for the further processing thereof, it is proposed that transition metals or transition metal compounds are subsequently deposited on the freed surface of the coating to form a top layer. The invention also relates to a method for producing press-hardened components from the aforementioned steel sheets or steel strips with an aluminium-based coating.

The invention relates to a method for coating a steel sheet or steel strip to which an aluminium-based coating is applied in a dip-coating process and the surface of the coating is freed of a naturally occurring aluminium oxide layer. In order to provide a low-cost method for coating steel sheets or steel strips that makes the steel sheets or steel strips outstandingly suitable for the production of components by means of press hardening and for the further processing thereof, it is proposed that transition metals or transition metal compounds are subsequently deposited on the freed surface of the coating to form a top layer. The invention also relates to a method for producing press-hardened components from the aforementioned steel sheets or steel strips with an aluminium-based coating.

A method of forming a shaped steel object, includes cutting a blank from an alloy composition. The alloy composition includes 0.1-1 wt. % carbon, 0.1-3 wt. % manganese, 0.1-3 wt. % silicon, 1-10 wt. % aluminum, and a balance being iron. The method also includes heating the blank to a temperature above a temperature at which austenite begins to form to generate a heated blank, transferring the heated blank to a die, forming the heated blank into a predetermined shape defined by the die to generate a shaped steel object, and decreasing the temperature of the shaped steel object to ambient temperature. The heating is performed under an atmosphere comprising at least one of an inert gas, a carbon (C)-based gas, and nitrogen (N.sub.2) gas.

A method of forming a shaped steel object, includes cutting a blank from an alloy composition. The alloy composition includes 0.1-1 wt. % carbon, 0.1-3 wt. % manganese, 0.1-3 wt. % silicon, 1-10 wt. % aluminum, and a balance being iron. The method also includes heating the blank to a temperature above a temperature at which austenite begins to form to generate a heated blank, transferring the heated blank to a die, forming the heated blank into a predetermined shape defined by the die to generate a shaped steel object, and decreasing the temperature of the shaped steel object to ambient temperature. The heating is performed under an atmosphere comprising at least one of an inert gas, a carbon (C)-based gas, and nitrogen (N.sub.2) gas.

A method of forming a shaped steel object is provided. The method includes cutting a blank from an alloy composition including 0.05-0.5 wt. % carbon, 4-12 wt. % manganese, 1-8 wt. % aluminum, 0-0.4 wt. % vanadium, and a remainder balance of iron. The method also includes heating the blank until the blank is austenitized to form a heated blank, transferring the heated blank to a press, forming the heating blank into a predetermined shape to form a stamped object, and decreasing the temperature of the stamped object to a temperature between a martensite start (Ms) temperature of the alloy composition and a martensite final (Mf) temperature of the alloy composition to form a shaped steel object comprising martensite and retained austenite.

A method of forming a shaped steel object is provided. The method includes cutting a blank from an alloy composition including 0.05-0.5 wt. % carbon, 4-12 wt. % manganese, 1-8 wt. % aluminum, 0-0.4 wt. % vanadium, and a remainder balance of iron. The method also includes heating the blank until the blank is austenitized to form a heated blank, transferring the heated blank to a press, forming the heating blank into a predetermined shape to form a stamped object, and decreasing the temperature of the stamped object to a temperature between a martensite start (Ms) temperature of the alloy composition and a martensite final (Mf) temperature of the alloy composition to form a shaped steel object comprising martensite and retained austenite.

The invention provides a component formed of an aluminum alloy for use in a vehicle, for example an automotive vehicle component requiring high strength, light-weight, and a complex three-dimensional shape, and a method of manufacturing the component. The method begins by providing a blank formed of an aluminum alloy which is already solution heat treated and tempered, and thus has a temper designation of about T4. The method further includes heating the blank to a temperature of 150° C. to 350° C., preferably 190° C. to 225° C. The method next includes quickly transferring the blank to a hot or warm forming apparatus, and stamping the blank to form the complex three-dimensional shape. Immediately after the forming step, the component has a temper designation of about T6, but preferably not greater than T6, and thus is ready for use in the vehicle without any post heat treatment or machining.

This steel sheet for hot stamping includes a base material, an Al-Si alloy plating layer in which the Al content is 75 mass% or more, the Si content is 3 mass% or more and the total of the Al content and the Si content is 95 mass% or more and a Ni plating layer in which the Ni content is more than 90 mass% in this order, the chemical composition of the base material is, by mass%, C: 0.01% or more and less than 0.70%, Si: 0.005% to 1.000%, Mn: 0.40% to 3.00%, Nb: 0.010% to 0.200%, a solid solution of Nb: 0.010% to 0.150%, sol. A1: 0.00020% to 0.50000%, P: 0.100% or less, S: 0.1000% or less, N: 0.0100% or less, Cu: 0% to 1.00%, Ni: 0% to 1.00%, V: 0% to 1.00%, Ti: 0% to 0.150%, Mo: 0% to 1.000%, Cr: 0% to 1.000%, B: 0% to 0.0100%, Ca: 0% to 0.010%. REM: 0% to 0.300%, and a remainder: Fe and an impurity, the Al-Si alloy plating layer has a thickness of 7 to 148 .Math.m, and the Ni plating layer has a thickness of more than 200 nm and 2500 nm or less.

This hot-stamping formed body has a predetermined chemical composition and has a metallographic structure consisting of, by area ratio, a total of 10% to 30% of ferrite and granular bainite and a remainder in microstructure consisting of one or more of martensite, bainite, and tempered martensite, and, in textures of a surface layer region and an inside region, ratios between a pole density of an orientation group consisting of {001}<1-10> to {001}<−1-10> and a pole density of an orientation group consisting of {111}<1-10> to {111}<−1-12> are controlled.