A resistance spot welded joint of an aluminum material is obtained by joining a stack of a plurality of aluminum materials by spot welding. A nugget formed by the spot welding includes a solidified part of the aluminum materials and a shell having a different solidification structure from the solidified part. The shell is formed annularly in a cross-section of the nugget in a stacking direction of the aluminum materials. The solidified part and the shell are alternately arranged from an outer edge of the nugget toward a nugget central part.

Aluminum-base alloy workpieces have surfaces with films of aluminum oxide which inhibit good contact with weld faces of resistance spot weld electrodes and the faying surfaces of, for example, sheet workpieces stacked for welding. Sometimes, the surfaces of the sheets also are coated with an adhesive or a sealer which further complicates welding. But in accordance with this invention, weld faces of opposing, round, copper welding electrodes are pressed against opposite outside surfaces of the sheets at a spot weld site and weld current is applied to the electrodes in accordance with a three-stage weld schedule to better form each weld. The weld schedule comprises a Conditioning stage (stage 1), a weld nugget Shaping stage (stage 2), and a weld nugget Sizing stage (stage 3).

A combined stackup apparatus with a perforated interlayer for resistance spot welding is provided. The apparatus comprises a first metal sheet of a first material and a second metal sheet of a second material. The apparatus further comprising a perforated interlayer disposed between the first metal layer and the second metal layer. The perforated interlayer is made of one of the first and second materials. The perforated interlayer has a plurality of perforations formed therethrough. Each perforation has a perforation size of between about 0.1 mm and about 3 mm.

A spot welding method includes a heating step of energizing an electrode in pressure contact with an Al alloy member to heat and melt a join part by resistance heating and a cooling step of cooling the join part after the heating step in a state in which the electrode is in pressure contact with the Al alloy member. The alloy is a wrought alloy of Mg: 0.2 to 1.2 mass %, Si: 0.4 to 1.5%, and Cu: 1.1% or less or a casting alloy of Si: 7 to 11% and Mg: 0.1 to 0.4% with respect to 100% as a whole. The cooling step includes a first cooling process performed with a reduced amount of input energy to the join part as compared with the heating step and a second cooling process performed after the first cooling process at a higher cooling rate than that in the first cooling process.

A welding assembly including a current generator, a first electrode electrically coupled to the current generator, the first electrode including a first engagement surface, a second electrode electrically coupled to the current generator, the second electrode including a second engagement surface, a width-determining fixture positioned between the first electrode and the second electrode to define a welding volume having a width, and an electrically nonconductive material positioned to electrically insulate at least one of the first electrode and the second electrode from an electrical conductor outside the width.

A welding electrode includes a weld face that has a convex base weld face surface and a plurality of ringed ridges that are radially spaced apart on the base weld face surface and surround a central weld face axis. The plurality of ringed ridges including an innermost ringed ridge and an outermost ringed ridge. The innermost ringed ridge is located closest to the central weld face axis and rises above a central portion of the base weld face surface, and the outermost ringed ridge is located farthest from the central weld face axis and rises above an outer peripheral portion of the base weld face surface. At least one of the plurality of ringed ridges is a discontinuous ringed ridge.

Provided is a method of welding laminated metal foils that can prevent blowholes and spatter from being formed. It is a method of welding laminated metal foils sandwiched between a pair of metal plates to the pair of metal plates. The method of welding laminated metal foils sandwiched between a pair of metal plates to the pair of metal plates includes locally pressing and crimping the laminated metal foils sandwiched between the pair of metal plates at a welding point in a laminating direction, and welding the crimped pair of metal plates and laminated metal foils at the welding point.

A resistance-spot-welded aluminum joint having a type of a nugget that can reduce variations in cross tension strength. The resistance-spot-welded aluminum joint is obtained by layering a plurality of aluminum members and welding the aluminum members together by resistance spot welding. In a cross section of an interface between the aluminum members, a weld nugget formed as a result of the resistance spot welding has a plurality of blowholes aggregated in a central area of the weld nugget within the interface. In a cross section taken in a layered direction of the aluminum members extending through the center of the weld nugget, a blowhole with a maximum size of the plurality of blowholes is formed at a position where the blowhole extends through a center line of the weld nugget extending in the layered direction.

Texture for breaking oxide layers on an electrode and a tool applying texture to an electrode is disclosed. The tool may be used during a pattern creating process where the texture is applied to the electrode tip, or may be used during a re-conditioning process where a new texture is applied to a deteriorated electrode tip. The textured surface may include a pattern of raised or depressed features (teeth, knurls, protrusions, depressions, ridges, asperities, cross-hatches, parallel or non-parallel lines, star shapes, triangles, hexagons, etc.). The tool includes a plate having an upper side and a lower side, and a texture surface is arranged on one or both of the upper and lower sides of the tool. The tool's texture surface may include various asperities or patterns, which are imprinted onto the electrode tips by squeezing the electrodes against the upper and lower sides of the tool.

Provided is a spot welding machine able to perform spot welding in which the desired nugget size is formed while suppressing spatter even if the strengths or thicknesses of the metal sheets change, the machine comprising: a pair of electrode tips, a pair of pressing members arranged around the tips, a first power supply, first and second drive mechanisms, and a pressing force control part, wherein the tips and the pressing members are respectively arranged facing each other so as to be able to sandwich a set of sheets between them, the first drive mechanisms give pressing forces pressing the tips against the sheets, the second drive mechanisms give pressing forces pressing the pressing members against the sheets, and the control part independently controls the pressing forces given by the first and second drive mechanisms.