PSI - Issue 75

Mehdi Ghanadi et al. / Procedia Structural Integrity 75 (2025) 457–466 Mehdi Ghanadi et al./ Structural Integrity Procedia (2025)

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shielding gas to protect the weld from contamination, while Böhler union X96 was the welding wire. The wire diameter was 1.0 mm for the 2 mm plates and 1.2 mm for 16 mm plates, ensuring proper fusion and weld quality. The welding was performed in the PB position with DC+ polarity and a 22° transverse torch angle. The welding parameters are shown in Tab. 1.

Table 1: Welding parameters.

Wire feed rate

Wire stick out

Torch angle

Preheat /interpass

Wire size

Ampere

Voltage

Travel speed

Heat input

Specimen

(Fore- back hand)

(mm)

(m/min)

(A)

(V)

(mm)

(cm/min)

(Kj/mm)

(°C)

T2B T2C

1.0 1.0 1.2 1.2

4.4 4.5

134-138 138-140 315-320 275-320

17 17

14 14 15

15°

50 50

0.22-0.23

22-25 22-25 22-90 22-73

5°

0.23

T16B T16C

11

30.5-32

10°

40-50 40-50

0.97-1.18 0.77-1.10

11.7

29-30

15-25

5°

The plates were initially tack-welded to hold them in place, ensuring proper alignment. Following this, a continuous weld was applied to create a strong, permanent bond. Throughout both the tack welding and continuous welding processes, proper clamping techniques were employed to secure the plates firmly and minimize distortion. The clamping ensured that any thermal expansion during welding minimized angular misalignment, maintaining the integrity of the welds and the overall structure. The micrographs of the welds presented in Fig. 3 reveal that for the specimen with a thickness of 2 mm, a single-pass weld is adequate. However, three welding passes are required for the 16 mm thick specimen due to several factors, including achieving adequate penetration and reducing defects such as lack of fusion or incomplete penetration. In addition, multi-pass welding effectively controls residual stresses and distortions, enhancing weld integrity and overall mechanical performance. A detailed comparison shows that the toe radius is larger in the welded joint with a 2 mm plate thickness, whereas the weld angle is larger in the 16 mm.

Figure 3.Cross-sectional micrograph of test specimens with 2 mm and 16 mm plate thickness.