JPS55117579A - Resistance welding method of annealing portion near weld zone of steel - Google Patents

Abstract

PURPOSE: To readily and surely weld the welding works of various shapes by declining and supplying, for the specified time, the current smaller than welding current and the current approximately the same as this, respectively, betweem the sub-electrodes spacing suitably from main electrodes before and after current supply to the main electrodes which sandwich the welding works under pressure.

CONSTITUTION: For example, the weld zone of a plate material 13 which is not "hardened" and a curved round bar 15 such as spring steel which is "hardened" is sandwiched under pressure by main electrodes 17, 19. The round bar 15 is spaced at a suitable distance from the main electrode 17 and is pressed by the sub-electrodes 21, 23 in the position where it is sandwiched. Thence, a switch 29 is turned on to supply the current 35 smaller than welding current between the sub- electrodes 21, 23 from a power source 33 for about 1/10 second, after which a switch 31 is turned on to supply current 37 to the main electrodes 17, 19 in superposition thereon. Then, when a nugget 25 is produced, the switch 31 is immediately opened to stop the current 37. For about 1 second after this stoppage, the supply of the current 39 to the sub-electrodes 21, 23 is continued and the current is gradually declined by a control unit 27 near the terminal period of the current supply, after which the current supply is stopped.

COPYRIGHT: (C)1980,JPO&Japio