Effect of Welding Current on the Mechanical and Structural Properties of TIG Welded Aluminium Alloy AA-5083

摘要

Purpose: In this study, structural and mechanical properties evaluation of AA-5083 alloy after single pass Tungsten Inert Gas (TIG) welding were investigated to reveal the weld strength, hardness of welded joints by using weld current as varying parameter. Design/Methodology/Approach: In this research, AA-5083 alloy plates were joined by TIG welding technique to examine optimal welding current. Welded specimens were investigated using optical microscopy, tensile and Vickers's micro-hardness tests. Optical microscopy was used to characterize transition sites of welded zone, HAZ and base metal. Tensile test was conducted to characterize weld strength by determining ultimate tensile strength and micro-hardness test was conducted to characterize the homogeneity of welding in terms of mechanical properties. Findings: Results have shown that optimum weld current out of the three weld currents used (70A, 75A and 80A) is 75A. Better micro structures and mechanical properties were found in the welded joints for the weld current 75A. Practical Implications: AA-5083 has excellent resistance to general corrosion and is used in marine applications. Resistance is excellent in aqueous solutions in the pH range 4 - 9. The corrosion resistance of aluminium alloys relies on a protective surface oxide film, which when damaged is readily repaired by the rapid reaction between aluminium and oxygen. It is commonly used in the manufacture of unfired, welded pressure vessels, marine, auto aircraft cryogenics, drilling rigs, TV towers and transportation equipment such as building of railroad cars, tip truck bodies and vehicle bodies and in missile components. Originality: TIG welding technique was successfully carried out on AA-5083 and better structural and mechanical properties were obtained using weld current as varying parameter.