Micro Hardness Lab Report

3.10 Results of Experiments
After performing all the experiments with predetermined values of process parameters, the tensile strength is measured and the micro hardness is measured. The results are given in the table 3.5.

Table: 3.5 Ultimate Tensile Strength and Micro hardness of SMAW & TIG for Experimentation
Exp. No Groove Angle (Degree) Root Face
(mm) Root Gap (mm) SMAW TIG UTS (MPa) Vickers Hardness
(Hv0.1) UTS (MPa) Vickers Hardness
(Hv0.1)
1 30 1 0 304 209 358 220
2 30 1.5 1 275 210 324 221
3 30 2 1.5 222 216 261 227
4 45 1 1 542 215 638 226
5 45 1.5 1.5 549 218 646 230
6 45 2 0 541 214 637 226
7 60 1 1.5 546 224 641 236
8 60 1.5 0 494 217 581 228
9 60 2 1 487 219 573 231

4. RESULT AND DISCUSSION
Following parameter
Main effect plot for tensile strength is as shown in fig 4.10. As a groove angle increases tensile strength also increases, highest tensile is obtained at 646 MPa.
Main effect plots for tensile strength are as shown in fig. 4.10. In order to see the effect of process parameter on tensile strength using L9 orthogonal array and experiments are performed and the experimental data are given in table 4.3. It is clear that as groove angle up to 45 degree increasing UTS increase after that UTS decrease. It was observed that as root face goes on increasing the UTS goes on decreasing. The effect of root gap increase to increase UTS as shown in fig. 4.10. Fig. 4.10 Main Effects Plot for UTS (MPa) of TIG Welding
Similarly, it can be seen that tensile strength is higher 646 MPa at 45 degree groove angle, 1 mm root face and 1.5 mm root gap. The tensile strength is very low 261 MPa at 30 degree groove angle, 2 mm root face and 0 mm root gap.
4.2 Analysis of Micro