A method of resistance spot welding workpiece stack-ups of different combinations of metal workpieces with a single weld gun using the same set of welding electrodes is disclosed. In this method, a set of opposed welding electrodes that include an original shape and oxide-disrupting structural features are used to resistance spot weld at least two of the following types of workpiece stack-ups in a particular sequence: (1) a workpiece stack-up of two or more aluminum workpieces; (2) a workpiece stack-up that includes an aluminum workpiece and an adjacent steel workpiece; and (3) a workpiece stack-up of two or more steel workpieces. The spot welding sequence calls for completing all of the aluminum-to-aluminum spot welds and/or all of the steel-to-steel spot welds last.

A method of resistance spot welding a steel workpiece and an aluminum or aluminum alloy workpiece, and a welding electrode used therein. In one step of the method a workpiece stack-up is provided. The workpiece stack-up includes a steel workpiece and an aluminum or aluminum alloy workpiece. Another step of the method involves contacting the aluminum or aluminum alloy workpiece with a weld face of the welding electrode. The welding electrode has a body and an insert. The insert is composed of a material having an electrical resistivity that is greater than an electrical resistivity of the material of the body. The weld face has a first section defined by a surface of the insert and has a second section defined by a surface of the body. Both the first and second sections make surface-to-surface contact with the aluminum or aluminum alloy workpiece amid resistance spot welding.

A series of many electrical resistance spot welds is to be formed in members of an assembled, but un-joined, body that presents workpiece stack-ups of various combinations of metal workpieces including all aluminum workpieces, all steel workpieces, and a combination of aluminum and steel workpieces. A pair of spot welding electrodes, each with a specified weld face that includes oxide-disrupting features, is used to form the required numbers of aluminum-to-aluminum spot welds, aluminum-to-steel spot welds, and steel-to-steel spot welds. A predetermined sequence of forming the various spot welds may be specified for extending the number of spot welds that can be made before the weld faces must be restored. And, during at least one of the aluminum-to-steel spot welds, a cover is inserted between the weld face of one of the welding electrodes and a side of a workpiece stack-up that includes the adjacent aluminum and steel workpieces.

Disclosed is a device for attaching corrective weights to a cylindrical outer surface of a rotor by means of electric resistance pressure welding, including an electrode (1) having a contact surface (20) for application against the rotor and comprising a supporting body (2) and a swinging body (6) having oppositely facing, congruent, spherical bearing surfaces (5, 8) suitable for abutting engagement with each other. The swinging body (6) is movably secured to the supporting body (2) such as to be able to perform limited swinging movements to all sides. A spring (14) arranged between the supporting body (2) and the swinging body (6) enables a gap to be produced between the spherical bearing surfaces (5, 8), whereby the contact surface (20) is in a position to align itself relative to the opposite surface of the rotor prior to pressure application by the welding force.

A radially slotted welding electrode is disclosed that may be used in conjunction with a companion second welding electrode to conduct resistance spot welding on a workpiece stack-up assembly that includes a steel workpiece and an overlapping adjacent aluminum workpiece, especially when an intermediate organic material layer is disposed between the workpiece faying surfaces of the steel and aluminum workpieces. The radially slotted welding electrode includes a weld face that has a central upstanding plateau and a convex dome portion that surrounds the central upstanding plateau and which includes a plurality of circumferentially spaced trapezoidal weld face sections that include transverse upstanding arcuate ridges. Together, the central upstanding plateau and the trapezoidal weld face sections of the convex dome portion define an annular channel that surrounds the central plateau and a plurality of radial slots that communicate with and extend outwards from the central channel.

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.

The present disclosure provides a welding electrode and methods of manufacturing the same. The welding electrode can include a composite body having a tip portion and an end portion. The composite body can include a shell defining a cavity through the end portion, the shell comprising a first metal that includes one or more of the following: a precipitation hardened copper alloy, copper alloy, and carbon steel. The composite body can also include a core within the shell, the core extending through the shell from the tip portion to the cavity, the core comprising a second metal that includes dispersion strengthened copper. The core and the shell have a metallurgical bond formed from co-extrusion.

Provided are a method and an apparatus for resistance spot welding in which preliminary current application is executed and then main welding is executed in accordance with master patterns of various parameters obtained during the preliminary current application. The main welding is executed under welding conditions of the master patterns, and whether a welding abnormality has occurred and whether the welding abnormality is likely to occur are determined. When the welding abnormality is likely to occur, the welding conditions for the main welding are corrected so as to prevent the welding abnormality. When the welding abnormality is unlikely to occur, the welding conditions for the main welding are corrected so as to match the master patterns.

A highly corrosion-resistant spot weldment can be produced at low cost without occurrence of prominent protrusions and the like on the surface. The spot weldment is joined by a nugget formed inside stacked sheet materials through bringing a pair of electrodes arranged opposite to each other into pressure contact with the stacked sheet materials from outside and energizing the stacked sheet materials from the electrodes. The nugget has a diameter that is ≥4√t (t: thickness of sheet material) and a flattening level of 3.5 to 8, which is a ratio of diameter to thickness. Both outer surface parts of the sheet materials are free from protrusions formed due to bulging of molten metal. Even when the electrodes are made of a copper alloy, the increased amount of Cu in the outer surface parts is 0.2 mass % or less with respect to the component composition before spot welding.

A welding portion inspection system includes a sensing head, and first and second electrodes that are disposed a predetermined distance from each other at one side of the sensing head, where front end portions of the first and second electrodes contact both sides of a welding portion to apply current such that a temperature of the welding portion is heated, and an infrared camera is disposed on the sensing head and detects a temperature distribution of the welding portion.