PSI - Issue 68

Ibrahim R. Awad et al. / Procedia Structural Integrity 68 (2025) 1024–1030 Ibrahim R. Awad / Structural Integrity Procedia 00 (2025) 000–000

1028

5

tensile strength of 532 MPa. Moreover, the elongation of the GTAW and SMAW joints is 8.4% and 9.68%, respectively, both significantly lower than the base metal's elongation of 30% (Çevik, 2018). The SMAW joint exhibits higher tensile strength than the GTAW joint, which can be attributed to the differences in heat input between the two processes. The heat input for GTAW (321.18 J/mm) is greater than that of SMAW (304.63 J/mm), resulting in different cooling rates that influence the microstructure and tensile properties of the welded joints. The HAZ and the transition zone between the weld metal and base metal are the most critical regions for the mechanical performance of welded joints. The joint efficiency, calculated according to Equation (2) (Ibrahim et al., 2021), indicates that the SMAW joint has a higher efficiency (98.8%) compared to the GTAW joint (93.2%). Furthermore, the tensile specimens from both weldments fractured in the HAZ, as shown in Figures 4 and 5. Joint efficiency % = UUl tl itmi maat et et et enns si liel es st rt reennggt ht hoof ft ht heewbealsdee md jeot ianl t ×100 (2) Table 2. Tensile properties of BM, GTAW, and SMAW welded joints.

Tensile properties Ultimate (MPa)

Materials

Location of fracture

Elongation (%)

Joint Efficiency

S275JR-BM

538.5

30

-

Gauge length

GTAW SMAW

502 532

8.40 9.68

93.2 98.8

HAZ HAZ

Figure 4. Fractured specimens of GTAW welded joints at HAZ.

Figure 5. Fractured specimens of SMAW welded joints at HAZ.