Characteristics of activator application in TIG and MIG welding of carbon steels

Abstract

This paper presents research results demonstrating that the steel refining grade has a significant effect on the penetration capability of the welding arc during TIG welding, whereas this effect is practically negligible in MIG welding. The influence of oxide-based fluxes on the arc penetration capability was also investigated. The results show that the effectiveness of these fluxes in improving weld penetration depends on the melting temperature of the activator and on the energy characteristics of the welding process, namely the arc heat power and the welding energy input (heat input to the welded joint). As these values increase, activation of the arc welding process requires the application of fluxes with higher melting temperatures. For TIG welding, within the optimum welding current range (up to 250 A), an increase in arc penetration is achieved by using activating fluxes consisting of combinations of medium-melting oxides and refractory oxides with melting temperatures up to 2400 °C. For improving arc penetration in MIG welding, combinations of medium-melting oxides and refractory oxides with melting temperatures exceeding 2500 °C are more suitable.