ALLOY FOR SPOT WELDING ELECTRODE FOR AL ALLOY SHEETS, MANUFACTURE THEREOF AND SPOT WELDING USING THIS

摘要

PURPOSE: To improve a service life of the alloy for the spot welding electrode for the Al (alloy) sheets by composing the alloy for the spot welding electrode of the specified quantity of Cr and the balance Cu with inevitable impurities. ;CONSTITUTION: The alloy for the spot welding electrode is composed of 1.5-20wt.% Cr and the balance Cu with inevitable impurities. The Cu-Cr solubility limit is 0.8% and even if more than that is added, it does not contribute to precipitation hardening. Cr more than the solubility limit is then added and Cr is subjected to crystallization dispersion in a Cu matrix, by which this Cr is oxidized on the electrode surface by welding heat. Composite material where a Cr oxide is dispersed in the matrix of a Cu-Cr precipitation hardening type alloy on the surface is formed. Accordingly, a reaction of the electrode to the Al (alloy) sheet which are materials to be welded is prevented, even if the oxide exfoliates during welding, Cr on the electrode surface is oxidized by welding heat and a regenerative function is provided. Consequently, heat conductivity and electric conductivity are satisfactory, high temperature strength and high temperature heat resistance are excellent and the service life of the alloy for the spot welding electrode for the Al alloy sheets can be improved.;COPYRIGHT: (C)1993,JPO&Japio