Investigations on the effect of alternating shielding gases on fusion welded characteristics of AA6061 alloy

Abstract

AA6061 aluminium alloys possess some unique properties like light in weight and high strength to weight ratio. They are becoming the most popularly used medium strength aluminium alloy in aerospace, marine, automobile and structural industries. With increased use of aluminium alloys in industries, a reliable joining technique needs to be developed for the effective utilization of aluminium alloys. Gas Tungsten Arc Welding (GTAW) and Gas Metal Arc Welding (GMAW) are the most extensive gas shielded arc welding processes used in joining of aluminium and its alloys due to their preferable flexibility and economy. But there are few problems like low welding speed, partial penetration and lack of the deposited metal occurred during this process. High solubility of hydrogen and other atmospheric gases in the molten state and formation of oxide layer are the major problems associated with this kind of joining process. Hence in this research, an attempt was made to increase the welding speed, to reduce the porosity and to maximize the mechanical properties of the GTAW and GMAW joints by the introduction of alternating shielding gases into the weld pool. In this investigation, a gas alternator is used to control and supply the argon and helium shielding gases cyclically to the weld pool for a particular period of time. newline