PSI - Issue 75

Carolina Payares-Asprino et al. / Procedia Structural Integrity 75 (2025) 489–500 C. Payares-Asprino et al./ Structural Integrity Procedia (2025)

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due to the weld metal restricting deformation [Odermatt et al.(2021)]. Tensile residual stress from welding (TRS) reduced the fatigue life of the DSS welds at different heat inputs, as shown in Figure 11. There is a strong correlation between residual stress and fatigue. Tensile residual stresses contribute to the initiation and propagation of cracks under cyclic loading conditions, significantly reducing the component's fatigue life [Webster and Ezeilo (2001)]. As can be seen in Figure 11, the fatigue life behavior corresponding to the base metal DSS was greater than the DSS weld at all heat inputs during welding. The results are consistent with those obtained by Xie et al. Figure 11 also shows the fatigue life of the DSS welds with weld bead decreases an average of 89.68% respect the base metal at stress of high strength of 500 MPa. However, when the machining process removed the weld bead, fatigue life increased by 81.91 % at all heat inputs. At a lower strength of 300 MPa, the fatigue life of the DSS weld decreases by an average of 96% concerning the base metal. The weld bead was removed throughout the milling process, with an increase of 89.28% in fatigue life concerning the DSS weld with weld bead. Arc welding typically generates residual tensile stresses in welded joints, leading to deteriorated fatigue performance of these joints. Volume expansion of the weld metal at high temperatures followed by contraction during cooling induces a local tensile residual stress state. The machining process to remove the weld-induced compressive residual stress inhibited the formation of subsurface cracks and reduced the mean stress applied during fatigue testing. These high compressive stresses reduce the mean stress applied in the fatigue testing and produce high fatigue strengths compared to those present in the DSS weld to maintain their weld bead. Results agreed with the results obtained by [Neto et al. (2022) and Chen and Yang (2002)], where residual stresses transformed from tensile to compressive values were beneficial in improving the fatigue of the component.

a)

b)

300 350 400 450 500 550 600

300 350 400 450 500 550 600

Machined weld bead Weld Bead Duplex 2205

Machined weld bead Weld Bead Duplex 2205

Stress (MPa)

Stress (MPa)

1.E+04

1.E+05

1.E+06

1.E+07

1.E+04

1.E+05

1.E+06

1.E+07

Cycles (N )

Cycles (N)

c)

300 350 400 450 500 550 600

Machined weld bead Weld bead Duplex 2205

Stress (MPa)

1.E+04

1.E+05

1.E+06

1.E+07

Cycles (N )

Fig. 11 Fatigue life of 2205 for the 2205 base metal and welds with weld bead and machined the weld bead: a) weld using HI of 0. 53 kJ/mm; b) weld using HI of 1.05 kJ/mm; c) weld using HI of 1.44 kJ/mm.