Effect of Number of Passes and Pass Directions in Friction Stir …
217
0
100
200
300
400
500
600
00:00
00:10
00:20
00:30
00:40
00:50
01:00
01:10
01:20
01:30
01:40
01:50
02:00
02:10
02:20
02:30
02:40
02:50
03:00
03:10
03:20
03:30
03:40
03:50
04:00
04:10
RetreaƟng side temp
Advancing side temp
Fig. 7 Temperature (°C) versus time graph (min) graph
3.1 Peak Temperature
Temperature plays a major role in grain size formation because higher temperature
means that the heat input is higher, and thus, the grains would be coarser and the
grain size would be more [14]. After an initial dwell time of 5 s, the pass was started
and the graphs are plotted accordingly. Figure 7 also shows that the temperature of
the advancing side is relatively higher than that of the retreating side [7], which is
because of the same direction of rotation and transverse movement in the advancing
side leading to higher heat generation [15].
Figure 7 is the average temperature versus time graph for the first pass of all the
samples, and it can be seen that the peak temperature has a value of around 550 °C.
3.2 Macrostructure
After the macro-examination of all the plates, plates B, D, and E showed through
void and cracks. The nugget region macro-cross section of sample Id D and E is as
shown in Figs. 8 and 9. This was the result of their process parameters, and therefore,
no further test except grain size measurement was conducted for them.
Fig. 8 Macro cross-section of sample Id-D
217
0
100
200
300
400
500
600
00:00
00:10
00:20
00:30
00:40
00:50
01:00
01:10
01:20
01:30
01:40
01:50
02:00
02:10
02:20
02:30
02:40
02:50
03:00
03:10
03:20
03:30
03:40
03:50
04:00
04:10
RetreaƟng side temp
Advancing side temp
Fig. 7 Temperature (°C) versus time graph (min) graph
3.1 Peak Temperature
Temperature plays a major role in grain size formation because higher temperature
means that the heat input is higher, and thus, the grains would be coarser and the
grain size would be more [14]. After an initial dwell time of 5 s, the pass was started
and the graphs are plotted accordingly. Figure 7 also shows that the temperature of
the advancing side is relatively higher than that of the retreating side [7], which is
because of the same direction of rotation and transverse movement in the advancing
side leading to higher heat generation [15].
Figure 7 is the average temperature versus time graph for the first pass of all the
samples, and it can be seen that the peak temperature has a value of around 550 °C.
3.2 Macrostructure
After the macro-examination of all the plates, plates B, D, and E showed through
void and cracks. The nugget region macro-cross section of sample Id D and E is as
shown in Figs. 8 and 9. This was the result of their process parameters, and therefore,
no further test except grain size measurement was conducted for them.
Fig. 8 Macro cross-section of sample Id-D