F Zakeri Shahroudi - Department of Metallurgy and Materials, Islamic Azad University South Tehran Branch , Tehran, Iran
A Halvaee - School of Metallurgy and Materials , College of Engineering , University of Tehran ,Tehran ۱۴۳۹۹ -۵۷۱۳۱ ,Iran

TIG welding is considered as one of the most common welding method because of high quality weld metal. For this reason, to increase the joint penetration during one-pass welding, actived-flux tungsten inert gas (A-TIG) welding on the 42CrMo4 steel type steel was studied. This paper presents effect of welding current and thickness of activating flux layer on the weld bead geometry.Two kinds of oxides Cu2O and Cr2O3 were used to investigate effect of activating flux on the weld bead geometry,microstructure and hardness in AISI 4140 steel. The effect of activated flux on metallurgicalproperties of the welds was discussed using result of scaning electron images, and EDS graphs of the weld zone for welds with or without fluxes. Vickers hardness with 500g force was performed. Experimental results showed that maximum depth of weld was obtained by using Cr2O3 activated flux but this flux decreased the depth to width ratio. All welds had martensite microstructure.

42CrMo4 heat treatable low alloy, TIG welding, Weld geometry, Activated oxide flux, ATIG Welding