| 摘要 |
PURPOSE:To secure a stable current path and to obtain a sound joining part by performing a pre-electrification with the current having small wave height value for specified wave height time prior to the joining of both metal plates. CONSTITUTION:The preelectrification current whose wave height time is 2mm/sec or less is passed between both electrodes 4a, 4b by a capacitor power source 11 with pressurizing the electrode 4a by the specific pressurizing force. A phosphate film 3 is removed by the electric resistance heating due to the pre-electrification only at the contact part of the projection 10 of a 1st metal plate 1a and a 2nd metal plate 1b. A stable current path is then secured with the direct contact of the mutual base metal parts of both metal plates 1a, 1b to arrange the preparation for the electrification of a rapidly instantaneous large current. When the welding current having larger wave height value than that of the precurrent and <2mm/sec wave height time is then passed, a thin welding nugget is formed to obtain a sound joining part. |
