**5. Result and discussion**

Testing of the welded plates carried out as per the standard procedure for measuring ultimate tensile strength (UTS) and yield strength (YS). **Figure 3** shows the specimen before the tensile test, which are cut from the welded plates. All the test specimens brokenearer to the weld zone, which is shown in **Figures 4–6** and the results of the tensile specimen are shown in **Table 5**.

From the results of tensile testing, we can easily see that the UTS values obtained for the three different pin geometries are different. The results of the square pin

**Figure 3.**  *Tensile test specimen.* 

**Figure 4.**  *Tested specimen.* 

*Effect of Variable Process Parameter on Ultimate Tensile Strength and Elongation of Aluminum… DOI: http://dx.doi.org/10.5772/intechopen.81083* 

#### **Figure 5.**

*Graph of experiment VS UTS.* 

**Figure 6.**  *Graph of experiment VS elongation.* 


#### **Table 5.**  *Tensile testing result.*

 and straight cylindrical pin gave better results compared to the threaded straight cylindrical pin. Material flow during the welding from the advancing side to the retracting side was good when using the square pin profile because the percentage elongation is highest in the square pin profile. When we are observing the results of elongation for experiments 4, 5, and 6, the heat generation is higher with the increasing tool rotation speed. The results of experiment 5 for UTS shows that the straight cylindrical pin profile gave better results at a low speed with high traverse speed. For generating heat, friction is necessary and if the traverse speed is more with high rotation speed then proper bonding of the two plates does not happen and the joint strength reduces as was observed in the results of experiment 1.
