One aspect of the present disclosure is a resistance spot welding apparatus for welding a workpiece made of layered metallic plates. The resistance spot welding apparatus includes a first electrode; a second electrode arranged such that the workpiece is interposed between the first electrode and the second electrode; and a pressure mechanism that applies pressure to the first electrode towards the first metallic plate by air. The pressure mechanism includes a piston coupled to the first electrode; a cylinder having an inner space that accommodates the piston; a first ventilation unit that supplies the inner space with air for applying pressure to the first electrode; and a second ventilation unit that discharges air from the inner space as pressure is applied to the first electrode. At least one of the first ventilation unit or the second ventilation unit includes two or more air passages that communicate with the inner space.

The invention relates to a method for measuring the electrode force on welding tongs. The welding tongs have a first electrode arm with a first electrode and a second electrode arm with a second electrode, said second electrode arm lying opposite the first electrode arm. At least one workpiece is clamped between the electrodes during the welding process. The aim of the invention is to provide a method for measuring the electrode force, said method providing an improved signal quality. The method has the following steps: a) measuring a first force acting on the first electrode, b) measuring a second force acting on the second electrode, and c) adding the measured first force and the measured second force, wherein an electrode force signal transmitted from the welding point to the electrodes is amplified, and an interference force signal introduced into the at least one workpiece from the outside and transmitted to the electrodes is eliminated.

A different material joining method sandwiches, with electrodes, a first joining member and a second joining member lower in melting point than the first member, applies pressure and electricity to them, and joins them in preset joint parts. The method includes forming a discontinuous abutting part beforehand in the joint part of at least one of the two members. The two members abut onto the abutting part in a discontinuous state. The method includes melting the second member by sandwiching the joint parts with the electrodes and applying pressure and electricity on the joint parts in a state where the two members abut onto each other in the joint parts while the abutting part is included. The method includes welding both the members by bringing a melting material of the second member into interface joining with a surface of the first member toward the second member.

An electrode and a device for resistance spot welding are capable of preventing an occurrence of a surface spatter by using magnetism. The electrode may include a shank and a welding tip mounted to an end of the shank. A magnetic unit is installed on an outer peripheral surface of the shank to form a magnetic field and to form a Lorentz force in a direction of rotation along a circumferential direction of the shank by the magnetic field and a current flowing through the shank.

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.

An apparatus includes a set of pre-welding electrodes including a shape-forming electrode having a contact face. The contact face has a shape-forming structure shaping a cross-section of a first segment of a first wire with a pre-welding shape upon compression of the contact face against the first segment. The pre-welding shape has a reentrance accommodating a second segment of a second wire to be welded to the first wire.

The present disclosure provides a method of resistance spot welding that can inhibit Liquid Metal Embrittlement-induced cracking in zinc-coated steel plates irrespective of the degrees of tensile strength. One aspect of the present disclosure provides a method of resistance spot welding. The method comprises welding a workpiece with a resistance spot welding apparatus. The workpiece includes two or more steel plates in an overlapping state. The two or more steel plates include at least one steel plate coated with zinc. The welding includes welding while compressing a high-tensile steel plate among the two or more steel plates in a direction intersecting a direction of a thickness of the high-tensile steel plate. The high-tensile steel plate has a tensile strength higher than a tensile strength of another steel plate among the two or more steel plates.

A spot welding apparatus (10) according to the present invention includes: a circular cylindrical cam (12) having an outer circumferential surface, in which a spiral-shaped large lead cam groove (12a) inclined at a steep angle and a spiral-shaped small lead cam groove (12b) inclined at a gentle angle are formed; and a pressurizing shaft (13) including a plurality of rollers (R1, R2) insertable into the respective cam grooves (12a, 12b) and configured to move along an axis of rotation of the circular cylindrical cam (12) when the circular cylindrical cam (12) rotates. When the rollers (R1, R2) are inserted into the large lead cam groove (12a), a roller (R1, R2) located at one end side of a row comes into contact with one of two sides surfaces of the cam groove (12a) and a roller (R1, R2) located at another end side of the row comes into contact with the other one of the two side surfaces of the cam groove (12a), and when the rollers (R1, R2) are inserted into the small lead cam groove (12b), each of the rollers (R1, R2) comes into contact with at least one of one side surface and the other side surface of two side surfaces of the cam groove (12b).

A spot welding method including: a main energization step of energizing a pair of opposing electrodes in pressure contact with both outer surfaces of a set of sheets where multiple sheet materials are stacked, thereby to cause melting between facing surfaces of the sheet materials; and a pressing variation step of, prior to the main energization step, causing a pulsation of pressing force applied to the set of sheets from the electrodes. A resin material such as an adhesive or a sealant may be interposed between the facing surfaces of at least a pair of the sheet materials. The period of the pulsation is 0.01 to 0.7 seconds. The amplitude of the pulsation is 10% to 90% with respect to a reference value of the pressing force. The set of sheets may include a first and a second steel sheet, and an aluminum alloy sheet that are stacked in order.