A spot welded joint of at least two steel sheets is provided. At least one of the steel sheets presents yield strength above or equal to 600 MPa, an ultimate tensile strength above or equal to 1000 MPa, uniform elongation above or equal to 15%. The base metal chemical composition includes 0.05≤C≤0.21%, 4.0≤Mn≤7.0%, 0.5≤Al≤3.5%, Si≤2.0%, Ti≤0.2%, V≤0.2%, Nb≤0.2%, P≤0.025%, B≤0.0035%, and the spot welded joint contains a molten zone microstructure containing more than 0.5% of Al and containing a surface fraction of segregated areas lower than 1%, said segregated areas being zones larger than 20 μm.sup.2 and containing more than the steel nominal phosphorus content.

A steel workpiece includes an alloy substrate comprising iron, about 1.4 to about 2.0 weight percent aluminum, and about 0 to about 1.0 weight percent silicon. The steel workpiece further includes a coating comprising zinc. A method of spot welding a workpiece stack-up that includes a pair of the steel workpieces includes providing the stack-up, contacting first and second electrodes to the steel workpieces, passing an electrical current through the stack-up, forming a weld nugget from molten mixing of the alloy substrates of the pair of steel workpieces, forming a boundary layer between the coating and the alloy substrate from dispersion of the coating into the alloy substrate and reaction of the zinc with the aluminum and the silicon to prevent molten mixing of the coating within the alloy substrate, and ceasing passage of the electrical current.

A component arrangement and a method for producing the component arrangement are provided. The component arrangement includes a first component and a second component, which are arranged in an overlapping arrangement and are connected by a laser fillet weld and at two fixing points arranged laterally offset from the laser fillet weld, one of the components is provided with at least one projection, which projects in the direction of the other component and which is arranged and formed such that, when the components are positioned correctly in relation to one another and are pressed together at the fixing points, a flange portion of the first component, set at an angle in the region of the laser fillet weld to be formed, is pressed onto the second component by way of the component edge. For sealing the component arrangement, the fixing points are arranged set back into the overlapping region with respect to the laser fillet weld, and at least between the fixing points there is formed a continuous bonding region, in which the first and second components are bonded to one another.

A method of forming an assembly includes providing a metallic first workpiece having base and a first layer disposed on the base and adhering a second layer onto the first layer. One of the first and second layers is formed of a zinc-based material formed of at least a majority of zinc, and the other of the first and second layers is formed of a metallic alloying material having a melting point higher than the melting point of the zinc-based material. Preferably, the first layer is formed of the zinc-based material, and the second layer is formed of the metallic alloying material with the higher melting point. A metallic second workpiece is disposed in contact with the second layer. A welding operation is performed to join the first workpiece to the second workpiece. A welded assembly is also provided.

An aspect of the present disclosure is to provide a method for manufacturing a welded structure capable of effectively suppressing welding LME cracks generated during spot welding of a zinc plated steel sheet having ultra-high strength, and a welded structure manufactured using the same.

A cold-rolled and heat-treated steel sheet having a microstructure consisting of, in surface fraction: between 10% and 30% of retained austenite, the retained austenite being present as films having an aspect ratio of at least 3 and as Martensite Austenite islands, less than 8% of the Martensite Austenite islands having a size above 0.5 μm, at most 1% of fresh martensite, at most 50% of tempered martensite, and recovered martensite containing precipitates of at least one element chosen among niobium, titanium and vanadium. A method for manufacturing the cold-rolled and heat-treated steel sheet is also described.

A welding element is operable for being connected to a workpiece using a welding method. The welding element comprises: a head and a shaft like anchor portion. The head includes a welding surface, a stop surface that is remote from the welding surface, and a plurality of pointed projections evenly and uniformly distributed over the entire welding surface. The shaft-like anchor portion extends along a longitudinal axis between a first end region and a second end region, with the first end region connected to the stop surface.

A spot welded joint of at least two steel sheets is provided. At least one of the steel sheets presents yield strength above or equal to 600 MPa, an ultimate tensile strength above or equal to 1000 MPa, uniform elongation above or equal to 15%. The base metal chemical composition includes 0.05≤C≤0.21%, 4.0≤Mn≤7.0%, 0.5≤Al≤3.5%, Si≤2.0%, Ti≤0.2%, V≤0.2%, Nb≤0.2%, P≤0.025%, B≤0.0035%, and the spot welded joint contains a molten zone microstructure containing more than 0.5% of Al and containing a surface fraction of segregated areas lower than 1%, said segregated areas being zones larger than 20 μm.sup.2 and containing more than the steel nominal phosphorus content.

A method for resistance spot welding comprising the following successive steps: —providing at least two steel sheets with thickness (th) comprised between 0.5 and 3 mm, at least one of the sheets being a zinc or zinc-alloy coated steel sheet (A) with a tensile strength (TS) higher than 800 MPa and a total elongation (TEL) such as (TS)×(TEL)>14000 MPa %, wherein the composition of the steel substrate of (A) contains, in weight: 0.05%≤C≤0.4%, 0.3%≤Mn≤8%, 0.010%≤Al≤3%, 0.010%≤Si≤2.09%, with 0.5%≤(Si+Al)≤3.5%, 0.001%≤Cr≤1.0%, 0.001%≤Mo≤0.5% and optionally: 0.005%≤Nb≤0.1%, 0.005%≤V≤0.2%, 0.005%≤Ti≤0.1%, 0.0003%≤B≤0.005%, 0.001%≤Ni≤1.0%, the remainder being Fe and unavoidable impurities, —performing resistance spot welding of the at least two steel sheets for producing a weld with an indentation depth (IDepth) on the surface of said steel sheet (A) such as: 100 μm≤(IDepth)≤18.68 (Zn.sub.sol)−55.1, wherein (IDepth) is in micrometers and wherein Zn.sub.sol is the solubility of Zn in the steel of sheet (A) at 750° C., in weight %.

Proposed is a resistance spot welding method to join parts to be welded which are a plurality of overlapping metal sheets, including: dividing a current pattern into two or more steps for welding; before actual welding, performing test welding; and subsequently, as actual welding, performing adaptive control welding, in which the two or more steps for welding include a step of securing a current path between the sheets directly below the electrodes and a subsequent step of forming a nugget having a predetermined diameter, and a welding interval time is provided between these steps. This method thus yields a good nugget without causing splashing even under special welding conditions.