Abstract: A method for joining different kinds of metal materials includes: preparing a rivet, a plurality of metal members, and a first electrode and a second electrode, each having shanks and electrode portions provided at the tips of the shanks; sandwiching the rivet and the plurality of metal members between a first electrode and a second electrode; and embedding the rivet into the metal member by pressurization and energization using the first electrode and the second electrode. The preparation step includes preparing, as the first electrode and the second electrode, two electrodes that satisfy a condition in which each of electrical resistance values of the first and second electrodes is lower than or equal to a sum of an electrical resistance value of the plurality of metal members to be joined and an electrical resistance value of the rivet.

Abstract: An iron rivet including a head and a shank, an aluminum plate, an iron plate, and first and second electrodes are prepared. A sandwiching step of sandwiching the rivet, the aluminum plate, and the iron plate between the first electrode and the second electrode, a penetration step of performing pressurization and current application by the first and second electrodes so that the shank penetrates through the aluminum plate, and a forming step of performing pressurization and current application by the first and second electrodes so that a nugget is formed between the shank and the iron plate are included. In the penetration step, the pressurization and current application is performed while air is blown to a side face of the shank so that the air hits a region around a boundary between the shank and the aluminum plate.

Abstract: An iron rivet including a head and a shank, an aluminum plate, an iron plate, and first and second electrodes are prepared. A sandwiching step of sandwiching the rivet, the aluminum plate, and the iron plate between the first electrode and the second electrode, a penetration step of performing pressurization and current application by the first and second electrodes so that the shank penetrates through the aluminum plate, and a forming step of performing pressurization and current application by the first and second electrodes so that a nugget is formed between the shank and the iron plate are included. In the penetration step, the pressurization and current application is performed while air is blown to a side face of the shank so that the air hits a region around a boundary between the shank and the aluminum plate.