Aluminum alloys (Al–Si–Mg alloys) have gathered wide acceptance in the fabrication of light weight structures requiring high strength-to weight ratio, such as transportable bridge girders. An improvised method is Pulsed current tungsten inert gas (PCTIG) welding (Developed in 1950s). The pulse current is more frequently used in manual welding because it has a lot of advantages in comparison to direct current. The main advantages are improved bead contour, greater tolerance to heat sink variations, lower heat input requirements, reduced residual stresses and distortion. In the present work to study the effect of PCTIG welding over continuous current TIG welding, work plates of 6 mm thickness have been used as the base material for preparing single pass welded joints. Single V butt joint configuration has been prepared for joining the plates. The filler metal used for joining the plates is AA 5356 (Al–5Mg (wt%)) grade aluminum alloy The preferred welding processes of moderately high strength aluminum alloy are frequently tungsten inert gas welding (TIGW) process. Two different welding techniques are used to fabricate the joints and they are: (i) continuous current TIG welding (CCGTAW) (ii) pulse current TIG welding (PCGTAW) processes. Argon (99.99% pure) has to use as the shielding gas. This report presents the effect of pulsed current TIG welding on mechanical behavior of high strength aluminum alloy joints, and studying about the grain refinement of weld bead, conducting the mechanical tests such as tensile test, impact test, and hardness test. Pulsed current welded joints have given superior mechanical properties comparative to continue current welded joints. PCTIG welded joints given high tensile strength, hardness and impact strength values. Current pulsing leads to relatively finer structure.

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The use of aluminum castings in the automotive industry has increased dramatically over the past two decades. The Al-Si system forms the basis of many important casting alloys, LM 0, LM 2, LM 4, LM 5, LM 6, LM 12, LM 13, LM 24 and LM 26 are the major cast alloys used in aerospace casting (e.g., fuel pump connectors) and premium automotive castings (e.g., suspension arms). The driving force for this increased use is vehicle weight reduction for improved performance, particularly fuel efficiency. In many cases the mechanical properties of the cast aluminum parts are superior to those of the cast iron or wrought steel parts being replaced; however, in some applications, defects in the cast microstructure undermine performance characteristics.