Issue 37

C. Patil et alii, Frattura ed Integrità Strutturale, 37 (2016) 325-332; DOI: 10.3221/IGF-ESIS.37.43 327 Chemical Composition % AA7075T 651 Elements Si Fe Cu Mn Mg Cr Ni Zn Ti Zr Required 0.4 0.5 1.2-2 0.3 2.1-2.9 0.18-0.28 - 5.1-6.1 0.2 - Contents 0.05 0.18 1.4 0.04 2.5 0.19 - 5.9 0.08 - AA6061T 6 Elements Required 0.4-0.8 0.7 0.15-0.40. 0.15 0.8-1.2 0.04-0.35 - 0.25 0.15 - Contents 0.62 0.45 0.2 0.13 1.05 0.09 - 0.03 0.07 - Table I : Chemical Composition of Base Aluminium Alloys Welding Procedures - FSW Method. The FSW joints were produced for similar alloys AA7075 and dissimilar alloys AA7075-AA 6061.The FSW welding parameter used in this experiment were tool rotation speed of 650,700, 800 rpm, 900 rpm and 1000 rpm; transverse speed of 30 mm/min, 35 mm/min and 40 mm/min. The tool tilt was maintained 0 0 during the experiment and plunge depth was of 6mm throughout the weld path. Tool tip plunge feed was 10 mm/min throughout the weld path. The plates to be welded by FSW process were fixed by a clamping fixture on a Joyti CNC vertical machining center PX20 series as shown in Fig. 2. The initial joint configuration was obtained by securing the plates in position using mechanical clamps. The direction of welding was normal to the rolling direction. Single pass welding procedure was used to fabricate the FSW joint. Figure 2 : Friction stirs welding on VMC machine with FSW joint. Welding Procedures - TIG Method. TIG welding was conducted on TIG weld machine along the rolling direction of plates. The TIG joints were also produced for similar alloys AA7075 and dissimilar alloys AA7075-AA6061.The The welding parameter used in TIG welding were; welding filler wire for TIG welding was Al-Si alloy with diameter of 4 mm, the flow rate of argon shield was 15 L/min, the welding voltage and current were 80 V and 280 A, respectively, and the speed of welding was 15 mm/s. Hardness Testing Method Using hardened steel ball indenter of 10mm diameter was fixed on the BHN machine demonstrated in the experimental set up as shown in Fig. 3.