PSI - Issue 33

Wei Song et al. / Procedia Structural Integrity 33 (2021) 795–801 Author name / Structural Integrity Procedia 00 (2019) 000–000

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EM and UM multipass welded joints. Noted that the SSPT effect only involved in the base metal for undermatched welded joints during the welding simulation processing. The SSPT factor significantly influences the residual stresses for both welded joints. The related results of evenmatched welds are presented in Fig. 5(a). For the multipass welding stress without the SSPT effect in evenmatched weldments, the high tensile residual stress for the longitudinal direction occurs in the weld metal surface. In contrast, the transverse residual stress in the weld center tended to be in a compressive state. Due to the SSPT effect, however, the tensile stress zones in longitudinal and transverse directions were transferred from the weld surface to the inside. Significantly, the surface passes in the evenmatched can induce the apparent compressive residual stress. On the other hand, it does not exert phase transformation behavior for the undermatched weld metal during the metallurgical analysis. From the computational residual stress of undermatched welded joints, the high tensile residual stress in the longitudinal direction appears in the boundary between the BM and its weldments. The stress distributions of the longitudinal direction demonstrate significant discontinuity between the weld metal and HAZ. On the other hand, the compressive transverse residual stress can also be observed near the weld center, while the maximum tensile residual stress in this direction occurs near the weld toe and weld root. Even though consider the SSPT effect for BM in Fig 5(b), it also does not change the residual stress distribution tendency. However, the transverse residual stress distributions with and without consideration of SSPT for UM welded joints become much less noticeable. The mismatch effect exhibits more apparently at the weld centerline, whereas it is not apparent outside of the HAZ.

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Fig. 6. The residual stress results comparisons between the FE models and experimental data for EM and UM welded joints in different directions. (a) Longitudinal stress in EM welds, (b) Transverse stress in EM welds, (c) Longitudinal stress in UM welds, (d) Transverse stress in UM welds. 3.2. Comparison of test data and calculated curves The residual stress variations for both EM and UM welded joints, including longitudinal and transverse