Linear Welding Process

Abstract--In present investigation, Al 6061 and Al 6063 aluminium alloy (6000 series) strips were joined by friction stir welding (FSW) process. Standard thickness (6 mm) aluminium pieces were joined by FSW under various traversing speed (40 and 70 mm/min) and rotational speed (800 and 1200 rpm). Two different pin profile tools (square and pentagonal) were selected for this work. The joint was characterized by applying various destructive and non-destructive tests. Three critical welding parameters were considered i.e. Tool rotation speed, transverse speed and tool geometry. The results showed that the tool pin profile has great influence on weld properties. Pentagonal tool pin profile performed much superior than square tool pin profile in

The higher value of tensile strength is obtained at higher welding speed (70 mm/min) at 1200 RPM of tool in both pin profile FSW tools. However, tensile strength in the case of (1200/70) is 120.3 N/mm2 which is higher than in case of (800/70) of the value is 107.8 N/mm2. This can be due to the welding parameters such as welding speed and rotational speed resulting in proper pressure and heat due to friction which affect the tensile strength as suggested by Kim et al. [18]. It is also reveals that as the welding speed increases with the rotation of tool increases, the ultimate tensile strength of welded Al alloys is also increases. This can be attributed due to suitable rotational speed leads to the appurtenant welding heat input and temperature which is associated with the fine weld performance. On the other hand, the heat input and stir effect is increases with increasing tool rotational speed which gives better mechanical properties of the joint. Heat input also affected by tool pin profile. But at the higher tool rotational speed, the tensile strength was higher at the starting and mid portion of the weld but it was lower at the end of the welding. The 2nd observation which is noted that the shape of tool pin have also a slightly influence on the tensile strength of welded zone of the specimens. Form the Fig. 2, it is clearly revels that the lowest tensile strength values are obtained for square profile pin tool at each welding condition as compared to pentagonal profile pin tool. Samples are welded by using pentagonal pin profile tool shows finer recrystallized grains [Fig. 4 (c); (d)] which cause higher degree of strength of the joints. Because of pentagonal pin profile caused higher degree of plastic deformation due to its higher eccentricity and its pulsation effect. Pentagonal pin profile of welded tool also resulted in higher