Résumé
Becaus hump formation limits welding productivity, better understanding of the humping phenomena during the welding process is needed to access process modifications that decrease the tendency to hump formation and then allow higher welding productivity. From a physical point of view, the mechanism identified is the Rayleigh instability initiated by a strong surface tension which induces a variation of kinetic flow. But the causes of the appearance of this instability have not yey been explained well enough.