In some examples, a technique including positioning supports such that the supports are between a first metallic substrate and a second metallic substrate, wherein an undulating member is located between the first metallic substrate and the second metallic substrate, the undulating member defining a plurality of first peaks adjacent to a first surface of the first metallic substrate and a plurality of second peaks adjacent to a second surface of the second metallic substrate, wherein a first support of the supports is positioned such that the first support extends between a first peak of the plurality of first peaks and the second surface of the second metallic substrate; welding the first peak to the first surface of the first metallic substrate in an area of the first support; and removing the first support by at least one of a thermal removal process or a chemical removal process.

An electrode-misalignment detection device in a resistance welder that joins members together by holding them between opposing electrodes and applying pressure and electricity thereto includes an electrode misalignment detector that simultaneously approaches outer peripheries of both electrodes to detect misalignment thereof. The electrode misalignment detector includes a clamping member, a signal generator, a non-closed-state detector, and a misalignment determiner. The clamping member is movable toward the electrodes to clamp them from opposite radially outer sides and is settable in a predetermined closed state when the electrodes are located at appropriate positions. The signal generator outputs a movement state signal according to a movement state of the clamping member. The non-closed-state detector detects that the clamping member is in a state other than the predetermined closed state based on the movement state signal. The misalignment determiner determines electrode misalignment if the clamping member is not in the predetermined closed state.

A method for joining two dissimilar metal plates having different volume resistivity with enhanced joint strength. The method includes overlaying a first metal plate made of first metal and a second metal plate made of second metal with higher volume resistivity and higher melting point in comparison with the first metal, bringing a pair of electrodes into contact with the surface of a portion of the second metal plate overlapping the first metal plate, supplying current between the electrodes so as to resistance-heat the second metal present in a current-flowing region to a temperature lower than the melting point of the second metal and higher than the melting point of the first metal, thereby partially melting the first metal plate with the heat so that an intermetallic compound is generated between the first and second metal plates, and thus joining the first and second metal plates via the intermetallic compound.

A welded joint manufacturing method includes: abutting a first electrode against a first steel sheet of a welded joint at a site A, which is a location at an outer side of a nugget in a sheet-plane direction in a plane running parallel to the first steel sheet; abutting a second electrode against a second steel sheet at a site B, which is a location at an outer side of the nugget in a sheet-plane direction in a plane running parallel to the first steel sheet of the welded joint, and positioned on an opposite side of the nugget from the site A; and passing a current through the welded joint between the first electrode and the second electrode.

A welded joint manufacturing method includes: abutting a first electrode against a first steel sheet of a welded joint at a site A, which is a location at an outer side of a nugget in a sheet-plane direction in a plane running parallel to the first steel sheet; abutting a second electrode against a second steel sheet at a site B, which is a location at an outer side of the nugget in a sheet-plane direction in a plane running parallel to the first steel sheet of the welded joint, and positioned on an opposite side of the nugget from the site A; and passing a current through the welded joint between the first electrode and the second electrode.

This spot welding method for an aluminum material comprises: a processing step in which, in a plan view, a circular emboss expanded in a direction of superposition on a second aluminum plate side is formed at a position-to-be-welded of a first aluminum plate; an arrangement step in which positions-to-be-welded are superimposed while the expansion side of the emboss faces the second aluminum plate, and the positions-to-be-welded are arranged between a pair of electrodes; a pressing step in which the superimposed aluminum plates are pinched between the electrodes, and a central side excluding a peripheral edge of the emboss is pressed; and an electrification step of performing pressing and electrification. An electrode having a tip diameter larger than the diameter of a root part of the expansion part of the emboss is used.

This spot welding method for an aluminum material comprises: a processing step in which, in a plan view, a circular emboss expanded in a direction of superposition on a second aluminum plate side is formed at a position-to-be-welded of a first aluminum plate; an arrangement step in which positions-to-be-welded are superimposed while the expansion side of the emboss faces the second aluminum plate, and the positions-to-be-welded are arranged between a pair of electrodes; a pressing step in which the superimposed aluminum plates are pinched between the electrodes, and a central side excluding a peripheral edge of the emboss is pressed; and an electrification step of performing pressing and electrification. An electrode having a tip diameter larger than the diameter of a root part of the expansion part of the emboss is used.

A method of manufacturing a joining apparatus includes: providing a first metal member including an opening and a joint structure; providing a second metal member including an outer circumferential wall capable of contacting an inner circumferential wall that surrounds the opening and a joined structure, to which the joint structure is joined; causing the first metal member and the second metal member to move relative to each other, bringing one of a first joining section, which is configured by the inner circumferential wall and the outer circumferential wall, and a second joining section, which is configured by the joint structure and the joined structure, into contact, and separating the other joining section; starting energization between the first and the second metal members; bringing components of the other joining section into contact with each other; and joining the first and second joining sections by the relative movement and the energization.

A method of manufacturing a joining apparatus includes: providing a first metal member including an opening and a joint structure; providing a second metal member including an outer circumferential wall capable of contacting an inner circumferential wall that surrounds the opening and a joined structure, to which the joint structure is joined; causing the first metal member and the second metal member to move relative to each other, bringing one of a first joining section, which is configured by the inner circumferential wall and the outer circumferential wall, and a second joining section, which is configured by the joint structure and the joined structure, into contact, and separating the other joining section; starting energization between the first and the second metal members; bringing components of the other joining section into contact with each other; and joining the first and second joining sections by the relative movement and the energization.

Provided is a resistance spot welding method suitable for manufacturing a weld joint exhibiting excellent delayed fracture resistance. The resistance spot welding method includes sandwiching two or more overlapped steel sheets between a pair of welding electrodes, applying current to the steel sheets while pressing the steel sheets, forming a nugget on overlapping surfaces of the steel sheets to join the steel sheets, and after the joining, directly or indirectly irradiating the nugget with sound waves having a frequency of 10 Hz or more and 100000 Hz or less so that a sound pressure level on a surface of the steel sheet is 30 dB or more.