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

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Figure 2. Microstructure of SMAW welded joint via optical microscopy: (a) FZ - HAZ interface, (b) microstructure of HAZ, (c) microstructure of FZ.

3.2. Hardness Measurements Figure 3 presents the hardness distribution across the FZ and HAZ of the GTAW and SMAW welded joints. In the GTAW welded joint, the hardness in the HAZ starts at 230 HV in the region farthest from the weld metal and increases steadily, reaching a peak of 286 HV near the FZ. Within the FZ, the hardness decreases, recording 240 HV at the center of the weld metal. In contrast, the highest hardness values in the SMAW welded joint were recorded in FZ (275 HV). This may be attributed to the fact that the heat input of the GTAW (321.18 J/mm) was higher than that of the SMAW (304.63 J/mm) which led to different cooling rates that affect the microstructure and hardness of the welded joints (Çevik, 2018; Pathak et al., 2021).

Figure 3. The hardness profile shows the hardness of the FZ and HAZ of GTAW and SMAW.

3.3. Tensile properties Table 2 presents the tensile properties of the GTAW and SMAW joints in comparison to the BM. The ultimate tensile strength of the GTAW joint in the transverse direction is 502 MPa, while the SMAW joint shows a higher