To provide a cold-pressure welding method which improves joint strength.
A plurality of small holes 7 are previously formed on an upper side joined material 5 of two joined materials 4, 5 to be joined by a cold-pressure welding method. Both of the joined materials 4, 5 are pressurized and restrained by a die 2 and a punch 3 and are plastically deformed so as to reduce thicknesses of parts with the plurality of small holes 7 formed. A material of the lower side joined material 4 is filled in the plurality of the small holes 7 by plastic flow in accordance with reduction of the thicknesses. Thereby, in addition to diffusion junction original to the cold-pressure welding method, caulking effect by the plurality of the small holes 7 is obtained with an increase of a junction area, and the joint strength between the joined materials 4, 5 is improved.
MATSUYAMA HIDENOBU
SHIMIZU AKIRA
SHIOTANI EIJI
IZAWA YOSHINORI
TERADA DAISUKE
NOSHI RYOJI
Tomioka Kiyoshi
Tsuyoshi Hashimoto