Patent ID: 8779320
Filing Date: 2014-07-15
Classification: B23K

Abstract:
1. A resistance welding method comprising: a heating step of Joule heating a welding portion of workpieces to be joined by supplying heating current to electrodes in outer contact with the workpieces; a first resistance measuring step of measuring a first electric resistance value (R a rest step of stopping the supply of the heating current for a predetermined time after the heating step ends; a second resistance measuring step of measuring a second electric resistance value (R a calculating step of calculating ratio of the second electric resistance value to the first electric resistance value or vice versa (R a determining step of determining whether the calculated resistance ratio or an index value obtained from the resistance ratio and indicating a weld state of the welding portion falls in a predetermined range or not; and a reheating step of carrying out the Joule heating again when the resistance ratio or the index value falls in the predetermined range; thereby at least part of the welding portion being melted and solidified to form a nugget.