Observations of repair process by friction stitch welding in simulated wet conditions—Flaws, microstructure and hardness evolutions in overlapping welds

Welding defects are common during the production of large welded structures. However, few studies have explored methods of compensating for clear welding defects without resorting to re-welding. Here, an ultrasonic peening method to compensate for the deteriorated mechanical properties of overlap weld defects without repair welding was studied. We experimentally investigated changes in the mechanical properties of defective welds before and after ultrasonic peening. The weld specimen with an overlap defect contained a large cavity-type defect inside the weld bead, which significantly reduced the fatigue life. When the surface of the defective test piece was peened, the fatigue life of the weld plate was restored, resulting in an equivalent or higher number of cycles to failure, compared to a specimen with a normal weld. The recovery of mechanical properties was attributed to the effect of surface work hardening by ultrasonic peening and the change in stress distribution. Thus, ultrasonic peening could compensate for the deterioration of mechanical properties such as tensile strength, fatigue life, and elongation due to overlap defects, without resorting to repair welding.

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Section: Methodsmentioning

confidence: 99%

“…Figure 1c,d show photographs of the welded plates with a normal weld and overlap defect, respectively. The overlap phenomenon in Figure 1d shows that the weld beads have an upward bias [20][21][22][23][24]. Flux-cored arc welding was performed at a welding current of 280 A and voltage of 30 V. Two types of test plates were produced.…”

Section: Methodsmentioning

confidence: 99%

Fatigue Life Improvement of Weld Beads with Overlap Defects Using Ultrasonic Peening

et al. 2023

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“…The downward force, induced plastic deformation, and rotating effects of the consumable plug facilitate the filling of the drilled hole. Wang et al (2019) reported that the continuously extruded viscoplastic material filled up the pre-drilled hole along the arc welded DH36 joint. This solid-state repair approach is independent of underwater pressure and depths.…”

Section: Introductionmentioning

confidence: 99%

Modeling and optimization of friction stir stitching of AISI 201 stainless steel via Box-Behnken design methodology

Ojo

Obasha

2022

Production Engineering Archives

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The paper investigates the modelling and optimization of the notch-repaired/friction stir stitched AISI 201 stainless steel welds via the use of a non-consumable tool-based repair process. The repair process employs a sequential hopping-stitching approach. This approach involves the application of two intercepted and completely overlapped plunging actions of a probe-less titanium carbide tool to create an effective refilling and repair of the notched zone. Box-Behnken design (BBD) was employed for the experimental planning, modelling, and optimization of the notch-repair process. Tool rotational speed, penetration depth and dwell time of the tool were the studied process parameters while tensile strength was the response variable. A quadratic model was identified as the best model for the notch-repaired welds based on the combination of a low sequential P-value of 0.008216, a high lack of fit P-value of 0.931366, and a close to unity adjusted and predicted R-square values. The process parameter and their interaction effects on the tensile strength of the repaired notch were identified via the ANOVA analysis. Plunge depth (main effect) and interaction effect of tool rotational speed and dwell time had significant influences on the notch-repair process and the resultant tensile strength of the AISI 201 stainless steel. The visual representations of these effects were shown through the 2D elliptical contour and 3D response surface plots. The optimized process parameters were identified as 1215.9795 rpm, 0.40262212 mm, and 5.98706376 s while the resultant notch-repaired joint yielded a tensile strength of 886 MPa, which is close to the predicted value.

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High-quality friction pull plug welding of AA2219-T87 plate with a thickness of 18 mm: Experimental characterization on shaping, microstructure and mechanical properties

Wang

Cui

et al. 2022

Materials Characterization

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Observations of repair process by friction stitch welding in simulated wet conditions—Flaws, microstructure and hardness evolutions in overlapping welds

Cited by 5 publications

References 12 publications

Fatigue Life Improvement of Weld Beads with Overlap Defects Using Ultrasonic Peening

Fatigue Life Improvement of Weld Beads with Overlap Defects Using Ultrasonic Peening

Modeling and optimization of friction stir stitching of AISI 201 stainless steel via Box-Behnken design methodology

High-quality friction pull plug welding of AA2219-T87 plate with a thickness of 18 mm: Experimental characterization on shaping, microstructure and mechanical properties

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