PSI - Issue 60

Aritro Chatterjee et al. / Procedia Structural Integrity 60 (2024) 13–19 Aritro Chatterjee, Arpan Mandal, Anoj Giri / Structural Integrity Procedia 00 (2019) 000–000

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Table 1. Chemical composition of the AA6082 -T6 base metal(wt.%). Remainder Si Fe Cu Mn Mg

Zn

Ti

Cr

Al

1.81

0.34

0.23

0.59

2.33

0.019

0.038

0.05

The FSW was performed to prepare the weld sample. Two pieces of Al 6086-T6 were aligned properly and then clamped in the fixture. The FSW machine was used to perform friction stir welding. The FSW tool (cylindrical pin having 6 mm diameter and shoulder diameter 25 mm) was used to join the Aluminum materials. Table 2 shows the welding parameters. Fig. 1 shows the work piece sample before and after the welding. The welding was performed at room temperature. Other parameters were tool plunging speed (50 mm/min), start dwell time (3 sec) and end dwell time (5 sec).

Table 2. FSW process parameters. Parameters

Value

Tilt angle

2°

Spindle speed

1200 RPM

Z – axis load

1000 kg

Table Travel speed

40 mm/min

Initial Z axis load

200 kg

Fig. 1. Friction Stir welding: (a) AA6082-T6 sample before welding; (b) After welding.

The DIC approach was used to estimate the residual stress of the welded part by mechanical relaxation method, which involves the capturing of speckle images before and after the drilling. After that the captured images were processed, which estimates the relaxed strain for a selected region of interest using the DIC image processing technique Suthar et al. (2022). For strain estimation by BHD-DIC approach, the speckle patterns were made on the surface of Al6082-T6 FSW weld joint (as shown in Fig. 2). The images were captured before and after the drilling at the desired locations. The setup consists of a camera, a drill machine with dial gauge. The dial gauge is used to precisely measure the depth of the drill. The camera is fixed in a linear movement automation set up and positioned perpendicularly above the work piece sample. Fig. 2(a) shows the set up used for the BHD-DIC residual stress measurement. The end mill cutter having 2 mm diameter was used for drilling purposes. A blind hole was drilled up to a depth of 1 mm. Fig. 2(b) shows the sample after blind hole drilling at the weld center region.