Experimental Investigation of Weld Strength In Pulsed Current TIG Welding of AA 5052 Alloys

Abstract

The main purpose of this study is to check the mechanical properties and the weld strength of aluminum alloy 5052 using pulsed current tungsten inert gas welding process. Identification of material is done and aluminum alloy 5052 alloys is identified as the base metal for the experimentation for the automobile and investment casting machinery applications. Process parameters are identified as peak current, base current and pulse per second and its range is identified from the pilot value experiments are peak current (200A, 220A & 240A), base current (100A, 110A & 120A) and pulse per second (100, 125 & 150) are selected for the current experimentation. General full factorial method is used for preparation of design of experimentation using Minitab version 21 software. Full factorial method gives 27 number of experiments which is beneficial in comparison to the other methods. For experimentation total 54 specimens of dimensions 100 mm x 50mm x 6mm were selected and edge preparation of 90º single v groove is done on all the specimens using hand grinding machines. As per the design of experiments PC TIG welding is done for single v groove butt joint. Surface finishing is done using hand grinding machine. Preparation of tensile specimens is done using plasma cutting machine of welded plate of dimension 200mm x 20mm. After doing tensile testing on universal tensile testing machine hardness of the heat affect zone, weld zone and base metal is tested using Rockwell hardness machine. Regression analysis and analysis of variance is done to check the regression equation, p-value and main effect plots for the experimental results. From the main effect plots obtained from the regression analysis shows that as peak current, base current and pulse per second increases the tensile strength got increased. As the peak current, base current and pulse per second increases the hardness of various zones got increased. The optimized graph obtained from response optimizer shows optimum values that are Peak current 240A, base current 120A and Pulse Per Second 150 which shows hardness as (HAZ= 97.5556, BM=96.8704, WZ= 99.4815) and Tensile Strength= 189.450. After the optimization, from the optimized values ,validation method has been carried out to validate this optimized values and after doing the experiments from the optimized input parameters the response parameters are Tensile strength as 188.57, hardness as (HAZ= 98.26, BM=99.28, WZ= 96.97) and the error found out to be for tensile strength=0.46%, hardness (HAZ=0.72%, WZ=0.21% and BM=0.11%) which are within the acceptable limits.