Methods for joining a first blank and a second blank, at least one of the first and second blanks comprising at least a layer of aluminum or of an aluminum alloy or a layer of zinc or of a zinc alloy. The method comprises selecting a first portion of the first blank to be joined to the second blank, and selecting a second portion of the second blank to be joined to the first portion, and welding the first portion to the second portion. The welding comprises using a filler metal laser beam and a welding laser beam, and displacing both laser beams in a welding direction to melt and mix a filler wire material with the melted portions of the two blanks. The present disclosure further relates to blanks obtained by any of these methods and to products obtained from such blanks.

A component connection includes a first component, which is made of a material attractable by a magnet, and a second component which lies directly or indirectly adjacent to the first component and which has a hole. A magnetic element is provided which covers the hole and attracts the first component such that both components are clamped together.

A steel sheet for the manufacture of a press hardened part is provided, having a composition of: 0.15%C%0.22%, 3.5%Mn<4.2%, 0.001%Si%1.5%, 0.020%Al0.9%, 0.001%Cr1%, 0.001%Mo0.3%, 0.001%Ti0.040%, 0.0003%B0.004%, 0.001%Nb0.060%, 0.001%N0.009%, 0.0005%S0.003%, 0.001%P0.020%. A microstructure has less than 50% ferrite, 1% to 20% retained austenite, cementite, such that the surface density of cementite particles larger than 60 nm is lower than 107/mm.sup.2, and a complement of bainite and/or martensite, the retained austenite having an average Mn content of at least 1.1*Mn %. Press-hardened steel part obtained by hot forming the steel sheet, and manufacturing methods thereof.

A method for welding a stack of sheets having a plurality of sheets of different materials is provided. In an aspect, the stack of sheets includes an aluminum sheet and a galvanneal steel sheet. In an aspect, the method includes resistively spot welding the galvanneal sheet to a hot-stamped steel sheet placed between the aluminum sheet and the galvanneal sheet, the sheet of hot-stamped steel including stress relief sections. The method further includes placing a metal foil on the aluminum sheet and vaporizing the metal foil to project portions of the aluminum sheet through the stress relief sections of the hot-stamped steel sheet to weld the portions of the aluminum sheet to the galvanized steel sheet. In another aspect, the method includes placing the metal foil on a raised portion of the aluminum sheet and projecting the raised portion of the aluminum onto the galvanneal steel sheet.

A method for connecting a first element with a second element, includes coupling a third element with the second element, coupling the third element with the first element by thermal joining, wherein the first element and the second element are made of different materials essentially incapable of being thermally joined with a welding process, and wherein the third element is arranged in an opening of the second element in a form fitting and/or force fitting manner.

A different material welded joint in which a first member made of a first material and a second member made of a second material having a melting point lower than that of the first material are joined to each other by welded parts at a plurality of welding sections, wherein the first member has a plurality of through-holes respectively corresponding to the plurality of welding sections and a filler material made of the second material is filled in the plurality of through-holes, and wherein apexes of welding beads of the welded parts, which are deposited and formed on a surface of the second member facing the through-holes, are formed independently of each other at each of the welding sections.

Steel sheet low in cost and improved in fatigue characteristics without causing a drop in the cold formability, characterized in that it comprises an inner layer and a hard layer on one or both surfaces of the inner layer, a thickness of the hard layer is 20 m or more and 40% or less of the thickness of the steel sheet, an average micro-Vickers hardness of the hard layer is 240 HV or more and less than 400 HV, an amount of C of the hard layer is 0.4 mass % or less, an amount of N is 0.02 mass % or less, a variation of hardness measured by a nanoindenter at a depth of 10 from the surface of the hard layer is a standard deviation of 2.0 or less, an average micro-Vickers hardness of the inner layer is 80 HV or more and less than 400 HV, a volume rate of carbides contained in the inner layer is less than 2.00%, and the average micro-Vickers hardness of the hard layer is 1.05 times or more the average micro-Vickers hardness of the inner layer.

A plate is continuously press-bent, into a shaped member having a recess opening at one surface (i.e., lower surface). Then, the plate is bent back by pressing, at the front and rear ends, covering the openings of the recess and a side frame having open cross sections, each with a gap, is thereby formed. In the forming step, the side frame is not welded and has open cross sections, each with a gap. The side frames are then subjected to the next step (i.e., step of assembling the seat frame). In the step of assembling the seat frame, the side frames and coupling members are welded together, constituting a substantially rectangular seat frame. As the side frames are so welded in step of assembling the seat frame, a rigid structure each having closed cross sections with no gaps is formed.

A method of welding an overlapped portion according to the present invention in which a plurality of steel sheet members are joined at an overlapped portion, and at least one of the plurality of steel sheet members contains martensite, includes: forming a spot-welded portion having a nugget in the overlapped portion; and emitting a laser beam to form a melted and solidified portion crossing an end of the nugget and located between the nugget and a position externally spaced apart from an end of the nugget by not less than 3 mm, this melted and solidified portion being formed in the steel sheet member containing the martensite so as to have a depth of not less than 50% of the thickness of the steel sheet member containing the martensite at a position externally spaced apart from the end of the nugget by 1 mm.

A method for manufacturing a strip having a variable thickness along its length, comprising the steps: an initial strip of constant thickness is provided; homogeneous cold rolling of the initial strip along its length in order to obtain an intermediate strip of constant thickness along the rolling direction; flexible cold rolling of the intermediate strip along its length in order to obtain a variable thickness strip, having, along its length, first areas with a first thickness (e+s) and second areas with a second thickness (e), less than the first thickness (e+s), continuous annealing of the strip. The plastic deformation ratio generated, after an optional intermediate recrystallization annealing, by the homogeneous cold rolling and the flexible cold rolling steps in the first areas is greater than or equal to 30%.