The Effect of Different Shielding Gas to Format of Porosity in Aluminium by using Gas Metal Arc Welding (GMAW) and Gas Tungsten Arc Welding (GTAW)

The low melting point of aluminium and its non-ferrous properties causes the difficulties in welding application in aluminium especially in term of shielding gas types that can cause porosity formation in weld resulting in pore cracking. Current research investigates the welding process on aluminium with different shielding gas which influence the porosity formation in the weld. A sheet of pure aluminium were cut into 150 mm length X 50 mm width X 6 mm thickness and 15 sheet of aluminium was prepared. Each 5 samples were weld using Metal Inert Gas (MIG), Metal Active Gas (MAG) and Tungsten Inert Gas (TIG) welding process. The welding parameters such as current, voltage, and gas flow have been measured during the welding process. The MAG which use active gas (carbon dioxide) welding proven to form more porosity compared to the MIG use inert shielding gas (argon) and TIG use inert shielding gas (argon).The use of active gas causes chemical reaction with aluminium and lack of protection to other gas such as hydrogen and nitrogen to react with aluminium producing air bubbles (pores) inside the weld. The use of inert gas such as argon reduce the porosity formation in the weld since it protect the weld pool from other gas such as oxygen and nitrogen from react with aluminium.