Issue 48

H. S. Patil et alii, Frattura ed Integrità Strutturale, 48 (2019) 377-384; DOI: 10.3221/IGF-ESIS.48.36 379 Yield Strength Ultimate Tensile Strength Elongation Reduction of Area 275 MPa 345 MPa >20% >30% Table 2 Mechanical properties workpiece material. The TIG welding operations were performed on the TIG weld machine with argon of 99.99% purity used as shielding gas. For uniformity titanium filler rod with 2 mm diameter was selected, as its composition was same as the composition of workpiece material as shown in table 1. Air-cooled torch with a titanium electrode rod with a 2 mm diameter was used. The electrode tip was of blunt point with a 45° angle. A direct-current, electrode-negative power supply device was used with a mechanized operation system in which the welding torch travelled at a constant speed. Single-pass, manual TIG welding was performed along the longitudinal centerline of the test specimen to produce a weld on a strip. The samples to be TIG welded were polished with 400 grit (silicon carbide) flexible abrasive paper to remove surface impurities and then it was cleaned with acetone. The welding of C.P titanium are conducted using GTA welding machine with air cooled torch head, as indicated in figure- 1(a). Welded joints samples of CP titanium for different weld process parameters are shown in figure 1(b). Figure- 1: Experimental setup and TIG welded joints for different parameters The welding parameters considered for this investigation were weld current, weld gap and gas flow rate on V-welding of CP Titanium materials with 3 levels each as shown in table 3. Welding Parameters Level 1 Level 2 Level 3 Welding Gap(mm) 0.5 0.75 1 Gas flow Rate(lit/min) 20 25 30 Current(A) 90 95 100 Table 3: Control parameters and their levels Taguchi method is a statistical method developed by Taguchi and Konishi which involves identification of proper control factors to obtain the optimum results of the process. Orthogonal Arrays (OA) are used to conduct a set of experiments and these experiments are used to analyze the data and predict the quality of weld joints produced. Here, an attempt has been made to demonstrate the application of Taguchi’s Method to improve the weld quality and properties of weld components. Welding quality also affects the life of titanium material joint and hence it is desirable to obtain higher quality of welding. The most suitable orthogonal array for experimentation is L9 array as shown in table-4.