Effects of Active Fluxes in Gas Metal Arc Welding

Abstract

In this paper the effects of active fluxes during gas metal arc welding (GMAW) Keywords Gas metal arc welding, Active flux welding, Weld geometry, Structural steel, Microstructure IntroductionNowadays the engineering industry has an increasing demand to enhance the welding technologies, in order to enable more productive and more efficient welding processes. One of the developing areas is joining thick plates with the minimum number of welding passes. Therefore deeper fusion depth is needed which increases the productivity areas, for example in case of welding high strength steels [1]). In order to increase productivity by reducing the welding passes, higher energy beam welding processes (e.g.: laser welding [2, 3], electron beam welding [4], plasma arc welding etc.) or novel welding methods (e.g.: friction stir welding [5]) can be used. In order to increase the productivity the usage of active fluxes gained attention in the recent times. By applying a thin layer of active flux on the surface prior welding, the penetration depth can be increased [6]. In case of tungsten inert gas (TIG) welding, with the usage of activated flux (A-TIG) 2-3 times deeper penetration can be achieved in Armco iron compared to the conventional TIG welding process [7]. In case of arc welding the driving force of the occurred flows in the weld pool can be originated from four different phenomena, the buoyancy, the surface-tension (which resulted in the so called Marangoni effect [7]), the high velocity movement of the arc plasma, and the Lorentz force [8,9]. Regarding the physical background of these processes, different theoretical models were established [10,11]. The models described; the vaporized ions from the flux play role in the increasing current density in the center of the welding arc, the applied flux reduces the surface tension and causes higher electric resistance, thus the size of the arc spot decreases [7]. All of the above-mentioned mechanisms have effect on the weld pool during A-TIG welding, however the main role is played by the reversed Marangoni flow [7][8][9]. The Marangoni effect is the mass transfer along an interface between two fluids due to surface tension gradient. In case of presence of active fluxes on the surface the mass transfer in the welding pool can be reversed from outward to inward which leads to reversed Marangoni flow. As a result of this inward convection the penetration depth is increasing [8,9]. The same phenomena can be achieved by adding oxygen to the shielding gas [12]. Most of the researches [13][14][15][16][17][18][19]

Effect of the Welding Filler Material on the Mechanical and Corrosive Behavior of Böhler W350 ISOBLOC Hot Forming Tool Steel

“…The welding parameters are shown in Table 2. Welding parameters were based on a previous study made in the department of the Budapest University of Technology and Economics [19][20][21].…”

Effect of activating fluxes on geometry, hardness, and microstructure of 316L stainless steel in GMAW

“…Balázs Varbai et al [13] applied eight AF during GMAW using ER70S-6 as welding wire and EN 1.0421grade structural carbon steel as base material. Weld geometry, microstructure, and hardness were studied.…”