A method to mitigate liquid metal embrittlement cracking in resistance welding of galvanized steels includes modifying at least one face of a steel member to create a first workpiece by: applying a zinc containing material in a first layer to the at least one face of the steel member; and spraying a second layer of a copper containing material onto the first layer of the zinc containing material. The at least one face of the first workpiece is abutted to a second workpiece of a steel material. A resistance welding operation is performed to join the first workpiece to the second workpiece. A temperature of the resistance welding operation locally melts the zinc containing material and the copper containing material to create a brass alloy of the zinc containing material and the copper containing material.

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%C0.4%, 0.3%Mn8%, 0.010%Al3%, 0.010%Si2.09%, with 0.5%(Si+Al)3.5%, 0.001%Cr1.0%, 0.001%Mo0.5% and optionally: 0.005%Nb0.1%, 0.005%V0.2%, 0.005%Ti0.1%, 0.0003%B0.005%, 0.001%Ni1.0%, 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 m(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 %.

A sensor element includes: an element body including, for example, a thermistor; paired lead wires drawn out from the element body; and stranded wires that are each obtained by twisting a plurality of core wires and are joined to the respective paired lead wires in a welding region. The welding region includes a main joining region provided in a predetermined region in an axis direction, and sub joining regions adjacent to the main joining region, and joining strength of each of the lead wires and the corresponding stranded wire is higher in the main joining region than in the sub-joining region.

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 method of resistance spot welding a workpiece stack-up that includes a first steel workpiece and a second steel workpiece. The method includes several steps. The first steel workpiece can have a first surface coating. One step involves applying a filler metal to a surface of the first steel workpiece. Another step involves bringing a surface of the second steel workpiece to adjoin the filler metal. Yet another step involves clamping a first welding electrode and a second welding electrode on the first and second steel workpieces. And another step involves passing electrical current between the first and second welding electrodes and hence through the filler metal. And yet another step involves terminating passage of the electrical current in order to establish a weld joint between the first and second steel workpieces.

A sensor element includes: an element body including, for example, a thermistor; paired lead wires drawn out from the element body; and stranded wires that are each obtained by twisting a plurality of core wires and are joined to the respective paired lead wires in a welding region. The welding region includes a main joining region provided in a predetermined region in an axis direction, and sub joining regions adjacent to the main joining region, and joining strength of each of the lead wires and the corresponding stranded wire is higher in the main joining region than in the sub-joining region.

A resistance spot welding method able to form a welded joint having delayed fracture resistance, comprising, in order, a step of applying a pressing force P1 (kN) to the plurality of steel sheets by welding electrodes while supplying a supplied current I1 (kA), a step of, while applying the pressing force P1, supplying a current Ic (kA) during a cooling time tc (s), a step of repeating two times or more a pressure force raising and lowering cycle of supplying a supplied current I2 (kA) to the welding electrodes while applying a pressing force P2 (kN) to the plurality of steel sheets by the welding electrodes during a pressing time tf (s), then immediately applying a pressing force P3 (kN) during a pressing time ti (s), a step of applying the pressing force P2 during the pressing time tf, and a step of releasing the pressing force and ending the supply of current, satisfying 0Ic<I1, 0.3I2/I1<1.0, P2/P11.2, P3<P2, and ti0.2.

A spot welding method able to simply prevent liquid metal embrittlement cracks in spot welding of plated steel sheets, comprising, before spot welding, removing the plating at least in a zone including the inside of a circle centered at a scheduled location where the center of the nugget is formed and having an outer circumference of the inside of the outer edge of a weld affected zone or a zone at the mated surfaces of the steel sheets to be welded at the inside of a circle sharing a center of a scheduled location becoming the center of the nugget formed at the mated surfaces of the steel sheets and having an outer circumference of the inside of the outer edge of a weld affected zone.

Provided is an automotive member, or particularly, a steel sheet having a tensile strength exceeding 900 MPa. The automotive member has a resistance weld for fixing two or more steel sheets containing a predetermined composition, in which a maximum hardness (HV.sub.BM) in a heat-affected zone of the resistance weld is at least 1.1 times hardness (HV.sub.W) of a nugget in the resistance weld formed in a softest steel sheet of a sheet set during resistance welding, and furthermore, an average grain size of a steel sheet structure of the heat-affected zone within 2 mm in a direction at a right angle to a sheet thickness from an end part of the nugget of the high-strength steel sheet is 3 m or less, and a minimum hardness (HV.sub.min) in the heat-affected zone is at least 90% of hardness (HV.sub.) of the high-strength steel sheet before the resistance welding.

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 0.05C0.21%, 4.0Mn7.0%, 0.5Al3.5%, Si2.0%, Ti0.2%, V0.2%, Nb0.2%, P0.025%, B0.0035%, 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 m.sup.2 and containing more than the steel nominal phosphorus content.