The present programme has been undertaken to evaluate the contribution of the different electrode tip growth mechanisms to the overall measured electrode tip growth when welding uncoated low carbon, hot-dip zinc coated, galvanneal and zinc-aluminium coated steels. Evaluation and analysis of the results has shown that changes in electrode mass and length can give an indication as to the relative contribution of the different electrode tip growth mechanisms to overall electrode tip growth. Besides, different electrode tip growth mechanisms predominate when different coated steels are welded: when welding zinc-aluminium coated steel, electrode tip growth is predominantly caused by rapid transfer of high copper content material from the electrode tip to the welded steel. The resultant length reduction of the truncated cone electrode geometry causes rapid electrode tip growth. When welding hot dip zinc coated steel electrode tip growth is caused in part by transfer of copper containing material to the welded sheet causing electrode length reduction. Electrode tip growth when welding galvanneal material arises from the reduction in length of the electrode, wing formation/mushrooming at the periphery of the electrode tip, build up of an alloy at the periphery of the electrode tip. The latter two processes account for approximately 50% of the observed tip growth.Le programme actuel a ete entrepris afin d'evaluer la contribution des differents mecanismes de croissance de l'extremite de l'electrode au phenomene global lors du soudage d'aciers bas carbone non revetus, d'aciers galvanises ou trempe et d'aciers electrozingues et revetus de Zn-Al. L'evaluation et l'analyse des resultats ont montre que des modifications de la masse et de la longueur de l'electrode peuvent donner des indications sur la contribution relative des differents mecanismes de croissance. En outre, les mecanismes predominants different lors du soudage de differents aciers revetus. Lors du soudage de differents aciers revetus zinc-aluminium, la croissance de l'extremite de l'electrode est surtout due au transfert rapide de la teneur elevee en cuivre de l'extremite de l'electrode a l'acier soude. La diminution de longueur du cone tronque entraine un evasement rapide de l'extremite de l'electrode. Lors du soudage d'aciers galvanise ou trempe, l'evasement est egalement du en partie au transfert du cuivre. Dans le cas d'aciers electrozingues, l'evasement est du au raccourcissement de l'electrode, et a la formation d'un champignon et d'un alliage a la peripherie de l'extremite de l'electrode. Ces deux processus expliquent a 50% environ le processus d'evasement.