A flat steel product for hot forming may be produced from a steel substrate that includes a steel comprising 0.1-3% by weight Mn and up to 0.01% by weight B, along with a protective coating that is applied to the steel substrate. The protective coating may be based on Al and may contain up to 20% by weight of other alloy elements. Also disclosed are methods for producing such flat steel products, steel components, and methods for producing steel components. Absorption of hydrogen is minimized during heating necessary for hot forming. This is achieved at least in part through an alloy constituent of 0.1-0.5% by weight of at least one alkaline earth or transition metal in the protective coating, wherein an oxide of the alkaline earth or transition metal is formed on an outer surface of the protective coating during hot forming of the flat steel product.

A method is for manufacturing a high-strength steel sheet having a tensile strength of more than 1100 MPa and a yield strength of more than 700 MPa, a uniform elongation UE of at least 8.0% and a total elongation of at least 10%, made of a steel containing in percent by weight: 0.1%≤C≤0.25%, 4.5%≤Mn≤10%, 1%≤Si≤3%, 0.03%≤Al≤2.5%, the remainder being Fe and impurities resulting from the smelting, the composition being such that CMnIndex=C×(1+Mn/3.5)≤0.6. The method includes annealing a rolled sheet made of said steel by soaking it at an annealing temperature TA higher than the Ac.sub.1 transformation point of the steel but less than 1000° C., cooling the annealed sheet to a quenching temperature QT between 190° C. and 80° C. at a cooling speed sufficient to obtain a structure just after cooling containing martensite and retained austenite, maintaining the steel sheet at an overaging temperature PT between 350° C. and 500° C. for an overaging time Pt of more than 5 s cooling the sheet down to the ambient temperature.

An alloy material is provided that has a chemical composition consisting of, in mass %, C: 0.030% or less, Si: 0.01 to 1.0%, Mn: 0.01 to 2.0%, P: 0.030% or less, S: 0.0050% or less, Cr: 28.0 to 40.0%, Ni: 32.0 to 55.0%, sol. Al: 0.010 to 0.30%, N: more than 0.30% and not more than 0.000214×Ni.sup.2−0.03012×Ni+0.00215×Cr.sup.2−0.08567×Cr+1.927, O: 0.010% or less, Mo: 0 to 6.0%, W: 0 to 12.0%, Ca: 0 to 0.010%, Mg: 0 to 0.010%, V: 0 to 0.50%, Ti: 0 to 0.50%, Nb: 0 to 0.50%, Co: 0 to 2.0%, Cu: 0 to 2.0%, REM: 0 to 0.10%, and the balance: Fe and impurities, and in which Fn1=Mo+(½)W is 1.0 to 6.0, and a yield strength at a 0.2% proof stress is 1103 MPa or more.

Disclosed is a multi-layer rolled composite board, comprising a transition layer provided between two adjacent composite layers, wherein the transition layer is an anisotropic steel sheet. Also disclosed is a manufacturing method for the multi-layer rolled composite board, the method comprising the following steps: (1) providing a transition layer between adjacent composite layers to assemble a blank, and creating a vacuum between the layers; and (2) performing composite rolling, comprising: heating the blank to 1100-1260° C. and maintaining the temperature for 0.6 h or above, then performing hot rolling at a temperature of Ar3 or above, with the final rolling temperature being controlled to be higher than 820° C., cooling at a speed of 30-100° C./s after rolling, and then coiling, with the coiling temperature being controlled to be 20-750° C. The multi-layer rolled composite board of the present invention can be greatly transformed according to different compositions and processes so as to achieve different strength grades ranging from 150 MPa to 1700 MPa, thereby providing the basis for different specific mechanical properties for the whole steel sheet.

An austenitic stainless steel material is provided that has high creep strength even when used at an average operation temperature of more than 600 to 750° C. after welding with higher heat input, and furthermore, has excellent stress relaxation cracking resistance even after use for a long time period at the average operation temperature after welding with higher heat input. The steel material has a chemical composition which consists of, in mass %, C: 0.030% or less, Si: 1.50% or less, Mn: 2.00% or less, P: 0.045% or less, S: 0.0300% or less, Cr: 15.00 to 25.00%, Ni: 8.00 to 20.00%, N: 0.050 to 0.250%, Nb: 0.10 to 1.00%, Mo: 0.05 to 5.00%, and B: 0.0005 to 0.0100%, with the balance being Fe and impurities, and a ratio of the dissolved N amount (mass %) with respect to the content of N (mass %) in the steel material is 0.40 to 0.90.

The present disclosure provides a method that ensures easily manufacturing an alloy ribbon piece having excellent soft magnetic properties. The method is a method for manufacturing an alloy ribbon piece obtained by crystallizing an amorphous alloy ribbon piece and including: increasing a temperature of the amorphous alloy ribbon piece to a crystallization starting temperature; and increasing the temperature of the amorphous alloy ribbon piece from the crystallization starting temperature to a crystallization process termination temperature equal to or less than a crystallization completion temperature. A temperature increase rate of the amorphous alloy ribbon piece in the increasing of the temperature of the amorphous alloy ribbon piece from the crystallization starting temperature to the crystallization process termination temperature satisfies ΔQ.sub.self≤ΔQ.sub.out+mcΔT where a self-heating amount, a heat discharge amount, a mass, a specific heat, and a temperature increase width of the amorphous alloy ribbon piece per unit time is ΔQ.sub.self, ΔQ.sub.out, m, c, and ΔT, respectively.

A Ni-plated steel sheet includes a base steel sheet and a Ni-based coating layer that is disposed on a surface of the base steel sheet. The distribution of carbon concentration in a depth direction obtained by performing GDS analysis on the Ni-plated steel sheet has a peak indicating the carbon concentration that is equal to or more than twice the carbon concentration of a thickness middle portion of the base steel sheet in the vicinity of an interface between the base steel sheet and the Ni-based coating layer.

Provided is a high strength steel sheet that has a predetermined chemical composition and is manufactured under optimum conditions, the high strength steel sheet having a steel microstructure including, by area, ferrite: 30% or more and 80% or less, tempered martensite: 3.0% or more and 35% or less, and retained austenite: 8% or more, wherein the quotient of the area fraction of grains of the retained austenite, the grains having an aspect ratio of 2.0 or more and a minor axis length of 1 μm or less, divided by the total area fraction of the retained austenite is 0.3 or more, wherein the quotient of the average Mn content (mass %) in the retained austenite divided by the average Mn content (mass %) in the ferrite is 1.5 or more.

Provided is a high strength steel sheet that has a predetermined chemical composition and is manufactured under optimum conditions, the high strength steel sheet having a steel microstructure including, by area, ferrite: 30% or more and 80% or less, martensite: 5% or more and 35% or less, and retained austenite: 8% or more, wherein the quotient of the area fraction of grains of the retained austenite, the grains having an aspect ratio of 2.0 or more and a minor axis length of 1 μm or less, divided by the total area fraction of the retained austenite is 0.3 or more, wherein the quotient of the average Mn content (mass %) in the retained austenite divided by the average Mn content (mass %) in the ferrite is 1.5 or more.

A forming sheet metal part (1) for a vehicle frame includes: a first portion (2) being locally heat-softened after the sheet metal part (1) has been formed out. The part (1) further includes a dedicated three-dimensional distortion-absorbing area (4), defining an internal boundary (6) within which the first portion (2) is to be locally heat-softened after the sheet metal part (1) has been formed out. The distortion-absorbing area (4) is dimensioned such that once said locally heat-softening step has been performed, the internal boundary (6) is adjacent to the first portion (2) and encloses the first portion (2) to absorb the dimensional distortions induced by the locally heat-softened first portion. The invention further relates to a method for producing a forming sheet metal part (1).