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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Residual stress modification methods alleviate tensile stress and induce compressive stress at the weld toe. An example of this approach is the high-frequency mechanical impact (HFMI) treatment, a highly effective technique for enhancing the fatigue strength of welded high-strength steel joints (Marquis et al., 2025). The Fig. 1, illustrates the fatigue life enhancement relative to the as-welded condition across various alternative welding techniques. The percentage increase for each method is displayed beneath, demonstrating that a smooth undercut can improve fatigue life by 270%.

Figure 1.Improving the fatigue life with alternative methods (Barsoum et al., 2018).

This investigation explores the effect of thinness and weld quality on transverse non-load-carrying attachment. Analysing fatigue test results and weld profile data helps improve understanding of the uncertainty and variation in fatigue life and the relationship between fatigue strength, specimen thickness, and weld quality. The findings suggest that reducing thickness and enhancing weld quality leads to improved fatigue strength. 2. Test specimens Test specimens used in this study are made from high-strength steel material S960QL produced by SSAB. The specimens were welded with the shape of a transverse non-load-carrying attachment. The load-carrying plate and attachment have the same thickness, with two variants; 2 mm and 16 mm. All welded specimens were cut to the specified dimensions, as illustrated in Fig. 2

Figure 2.Dimensions of test specimens.

The different test batches were produced in quality B and C, according to ISO 5817. The T2B, T2C, T16B, and T16C labelling methods distinguish series, with “T” denoting plate thickness and the final letter indicating weld quality. A submerged arc welding portal incorporating a torch holder for MAG welding was employed. The welding machine used was ESAB Aristo 5000U with U82 remote control. Mison 18 (82%AR, 18%Co2) was used as the