PSI - Issue 60

Rohan Nair et al. / Procedia Structural Integrity 60 (2024) 93–114 Rohan Nair / Structural Integrity Procedia 00 (2023) 000–000

105 13

2 3 4 5 6

288 288 267 274 276

332 334 315 312 315

15.1 17.7 13.9 15.4 13.8

Table 6: Tensile test results of long-seam and cir-seam welded coupons

Long-seam welding (Gauge length 50mm)

Specimen Identification nos.

Ultimate tensile Strength, MPa (Specification – 180)

Failure zone

0.2%Yield strength, MPa (Specification –140)

% Elongation (Specification – 3)

L1 L2 L3 L4 L5 L6

154 151 154 170 161 156

221 224 219 224 223 224

4.6 5.0 4.8 2.9 4.4 4.6

Heat affected zone Heat affected zone Heat affected zone Heat affected zone Heat affected zone Heat affected zone

Cir-seam welding (Gauge length 25mm)

Specimen Identification nos.

Ultimate Tensile strength, MPa (Specification – 180)

Failure Zone

0.2% Yield strength, MPa (Specification –140)

% Elongation (Specification –3)

Heat affected zone Heat affected zone Heat affected zone Heat affected zone Heat affected zone Heat affected zone

C1 C2 C3 C4 C5 C6

150 140 147 133 135 138

222 215 222 208 211 217

8.7

10.5

9.4

10.1

8.5 9.4

Results of Vickers microhardness [12] for long-seam and cir-seam welds are shown in Fig. 14 & Fig. 15 respectively. Two heat affected zones were noticed in the cross section of the etched specimen as shown in Fig. 14 depicting long-seam weld with shells on either side. Hardness at HAZ2 was found to be lower than weld and parent metal on both sides. The failure of the tensile specimen was also noticed to be in HAZ region. Fig. 15 depicts cir-seam weld with forging on left side and shell on right side of the weld. Hardness at HAZ is weaker on the shell side and that also indicates the failure zone during tensile testing.

Fig. 14: Stereo microscopic images of the long-seam weld specimen showing different regions of the weld cross section along with the microhardness values (VHN, load: 50gf) at weld, interface, HAZ1, HAZ2 and parent material regions.