Corrosion Resistance of TIG Welding Joint for Aluminium Alloy 6061- T6 in Sea Water at Different Velocities

Abdul RahimKhudadad, Mussa; Nife Frhan, Entsar

	Corrosion Resistance of TIG Welding Joint for Aluminium Alloy 6061- T6 in Sea Water at Different Velocities
Journal of Engineering and Sustainable Development
Article 1, Volume 18, Issue 6, 2014, Pages 113-125
Authors
Mussa Abdul rahimKhudadad; Entsar Nife Frhan
Abstract
An experimental investigation has been carried out on microstructure, micro hardness distribution and corrosion behaviour of weld butt joints of 6061 T6 aluminium alloy. Arc welding processes by tungsten inert gas (TIG) have been carried out on Rolled sheet of 4mm thickness to obtain many welding joints with dimension of (100 50 4)mm using ER4030 (Al Si5 ) as filler metal and argon as shielding gas. The other parameters were: welding current 180 amperes, voltage 20 volts, filler rod diameter 1.2 mm, welding speed120 mm/min, gas flow 20 L/min and two passes of the weld All welded pieces were tested by X-ray radiography and faulty pieces were excluded. The joints without defects were used to prepare many specimens for corrosion tests by the dimensions of (15153) mm according to ASTM G71-31 then Optical microscopy was used to observe the welded joint microstructure. Corrosion test was implemented by using potential static polarization measurements in seawater 3.5%NaCl at a temperature of 25°C, and different velocity (1, 2, and 3) m/min. The potential of circuit was determined by open circuit depending on AL in electrochemical series after that the rate of cell’s current is changed due to 100± (m v). The obtained results by Tafel equation shows that velocity contributed in increasing corrosion resistance of 6061 T6 Al alloy for all specimens and TIG weld joints give low corrosion rats than the bass metal because of changing in microstructure in the weld zone.
Keywords
TIG weld; corrosion resistance of Al alloys; sea water

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