A method of resistance spot welding an aluminum workpiece and an adjacent overlapping steel workpiece is disclosed in which a source of a reactive metal in a diffusible state is located along a faying interface of an aluminum workpiece and an adjacent overlapping steel workpiece. The source of the reactive metal in a diffusible state may take on a variety of forms including (1) a composite adhesive layer that includes reactive particles dispersed throughout a structural thermosetting adhesive matrix or (1) a reactive alloy layer that confronts and is in proximate contact with a faying surface of the aluminum workpiece. Once the source of a reactive material in a diffusible state is in place and the workpiece stack-up is assembled, an electrical current is passed through the workpiece stack-up and between a set of opposed welding electrodes at a weld zone to ultimately produce a weld joint.

A method for resistance welding a metallic component to a sandwich metal sheet with a thermoplastic layer disposed between two metallic cover layers may involve heating a region of the sandwich metal sheet to be welded such that the thermoplastic layer softens, displacing the thermoplastic layer from the region by compressing the cover layers, and welding the cover layers with the metallic component by means of a flow of electrical current in a first circuit via a first welding electrode disposed on a side of the sandwich metal sheet and a second welding electrode disposed on a side of the metallic component. The method for resistance welding has short cycle times, and a compact design and a process-reliable welded connection can be achieved. The method may further involve heating the region to be welded by a flow of current in a second circuit comprising the first welding electrode and an electrical conductor disposed between the first welding electrode and the sandwich metal sheet.”

A method for resistance welding a metallic component to a sandwich metal sheet with a thermoplastic layer disposed between two metallic cover layers may involve heating a region of the sandwich metal sheet to be welded such that the thermoplastic layer softens, displacing the thermoplastic layer from the region by compressing the cover layers, and welding the cover layers with the metallic component by means of a flow of electrical current in a first circuit via a first welding electrode disposed on a side of the sandwich metal sheet and a second welding electrode disposed on a side of the metallic component. The method for resistance welding has short cycle times, and a compact design and a process-reliable welded connection can be achieved. The method may further involve heating the region to be welded by a flow of current in a second circuit comprising the first welding electrode and an electrical conductor disposed between the first welding electrode and the sandwich metal sheet.”

A spot welding process which uses a metal insert as an insert between the sheets to be welded which belongs to the field of industrial welding, in order to prevent the presence of mark or indentation on the surface of the welds. After the welding process, as the metal insert material melts and dissolves between the overlapped sheets, the state of the art does not provide for the use of metal insert as an insert between the sheets, the spot welding process with insert between (2), made of metal powder or solid metal, which is introduced between the interfaces of the sheets (3) to be welded by the spot welding process, the insert (2) (3), by inert adhesive (4) or other material and process which performs this function, wherein during the melting process the metal insert (2) melts and dilutes together with the base material, i.e. the opposing metal plates (3). The alloy of the metallic insert (2) has chemical and physical properties compatible with the properties of the base metal sheets (3), the spot welding equipment requires that its contact electrodes (5) have the fully flat surfaces (6) and Or special contact geometry.

A mounting unit includes a mounting part for a mating surface of a basic structure which cannot be welded to the mounting part and a welding element fixed in a through-bore of the mounting part. The welding element corresponds to the bore and has a thickness at least as large as the mounting part. An annular groove is formed in the welding element. A part of the welding element bounding the groove on the outside forms a form-locking connection element expanded outward and fixing the welding element in the bore by a form-locking connection toward the mounting side. A central region radially within the annular groove is a welding surface for the mating surface, is aligned with or protrudes beyond a mounting-side edge region of the bore with an overhang and is aligned with or projects over the form-locking connection element. A production method is also provided.

A mounting unit includes a mounting part for a mating surface of a basic structure which cannot be welded to the mounting part and a welding element fixed in a through-bore of the mounting part. The welding element corresponds to the bore and has a thickness at least as large as the mounting part. An annular groove is formed in the welding element. A part of the welding element bounding the groove on the outside forms a form-locking connection element expanded outward and fixing the welding element in the bore by a form-locking connection toward the mounting side. A central region radially within the annular groove is a welding surface for the mating surface, is aligned with or protrudes beyond a mounting-side edge region of the bore with an overhang and is aligned with or projects over the form-locking connection element. A production method is also provided.

A method of adhesive weld bonding a light metal workpiece and a steel workpiece is disclosed that includes applying a plurality of discrete adhesive ribbons to a faying surface of the light metal workpiece, the faying surface of the steel workpiece, or both faying surfaces, and then assembling the workpieces together to establish one or more adhesive zones between the faying surfaces of the light metal and steel workpieces and a plurality of adhesive free zones amongst the adhesive zone(s). The method further includes forming a resistance spot weld that bonds the the light metal workpiece and the steel workpiece together at a spot weld location within one of the adhesive free zones. The formed spot weld includes a weld joint contained within the light metal workpiece that bonds to the faying interface of the steel workpiece.

A system and method of braze resistance spot welding of an aluminum component to a galvanized steel component involve providing an aluminum-side electrode having a first tip defining a rounded shape, providing a galvanized steel-side electrode having a second tip defining a flat shape, depositing a braze filler material between the aluminum and galvanized steel components at a desired location for a spot weld, performing a pre-heat including providing a first current across the electrodes for a first period such that the braze filler melts and removes a portion of a zinc coating from the galvanized steel component, and after performing the pre-heat, performing a spot weld between the aluminum and galvanized steel components by providing a second current across the electrodes for a second period such that the aluminum melts and the galvanized steel does not melt, wherein the second current is greater than the first current.

A system and method of braze resistance spot welding of an aluminum component to a galvanized steel component involve providing an aluminum-side electrode having a first tip defining a rounded shape, providing a galvanized steel-side electrode having a second tip defining a flat shape, depositing a braze filler material between the aluminum and galvanized steel components at a desired location for a spot weld, performing a pre-heat including providing a first current across the electrodes for a first period such that the braze filler melts and removes a portion of a zinc coating from the galvanized steel component, and after performing the pre-heat, performing a spot weld between the aluminum and galvanized steel components by providing a second current across the electrodes for a second period such that the aluminum melts and the galvanized steel does not melt, wherein the second current is greater than the first current.

A structural member is provided that includes a steel sheet with a tensile strength of 980 MPa or higher overlying another metal plate and joined thereto by welding, where a break initiating near a welded portion is less likely to be produced. A structural member (10, 10a, 10b, 10c) includes: a first member (1), the first member being a steel sheet with a tensile strength of 980 MPa or higher; a second member (2) overlying the first plate (1), the second member being a metal plate; a plurality of welded portions (3, 31, 32); a plurality of heat-affected zones (5, 51, 52) each formed to surround the corresponding one of the welded portions (3, 31, 32), the heat-affected zones having a Vickers hardness lower than that of the first member by 50 HV or more. A pair of edge sections (4) of the first member (1) are provided between adjacent heat-affected zones (5, 51, 52). The pair of edge sections (4) of the first member located between the adjacent heat-affected zones (5, 51, 52) extend to cross a line (LC1) linking the adjacent welded portions (3, 31, 32).