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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(hammer peening including HFMI, shot peening, and others) including their specific local material behavior. Finally, these results should be tested with variable amplitude fatigue data of specimen with varying residual stress conditions [Tareg (2018)]. The improvement and optimization of post-weld treatment in stainless steel are, to a large extent, a condition of the service life of the associated structures. In this regards, mechanical brushing and heat treatment are post-weld technique dedicated to the assembly of mechanically welded structures applicable in the aeronautics, food and transport sectors. Some studies have dealt with various techniques for post-treatment of welded joint [Kim et al. (2018), Guizani et al. (2021)]. They have revealed that such techniques improve the fatigue life strength of the welded steel structures. These techniques can be classified in weld geometry improvement method and residual stress methods. Mechanical and thermal post-welding treatment technique are applied in order to overcome the effects related to fatigue failure of welded joint. The post- treatment techniques such a re-melting, shot peening, grinding, ultrasonic peening, and special welding techniques allow a smooth transition between the different zones of the weldment, reducing the stress concentration that is produced by the welding process. A reported by Kim et. al (2018), these methods are usually applied to improve the fatigue strength of steel structure after welding and to extend the fatigue life of the treated specimen in the context of mechanical brushing. His test results showed that bristle roll-brush grinding introduced compressive residual stress and significantly increased fatigue limits by over 50% of the treated specimen using the mechanical brushing. Guizani et. al. (2021) uses two technique, mechanical brushing, and heat treatment at high temperature, to evaluate the fatigue behaviour of austenitic 316 L stainless steel. The brushed material specimen has the longest life just before fracture. It offers a longer life than the unbrushed sample. Welded joints are sensitive to fatigue failure due to cyclic loading, as well as fatigue crack propagation influenced by the distribution of welding residual stress. Weld residual stress often approaches, or exceeds the yield strength of the material, with serious implications for the integrity of engineering structures. The residual stresses that result from welding create complex crack propagation challenges, making it difficult to make accurate fatigue life predictions. Control of weld residual stresses can lead to increased fatigue life, corrosion control, and improved fracture response. The existence of weld-induced RS can be harmful to the structural integrity and behaviour of the weld structure, especially if the residual stresses are tensile stresses [Ramirez et al (2003)]. Many structural failures that are produced by fatigue, stress corrosion, and cracking are caused by tensile stresses as the material pulls apart after welding [NASA-STD-5006A (2015)]. Compressive residual stresses usually benefit performance since they prevent the origination and propagation of fatigue cracks, increasing wear and corrosion resistance. In the major cases, low-temperature abrasive machining tends to enhance the physical properties of the surface due to mechanical effects. Therefore, compressive stresses are induced in the same way as sandblasting or shot peening a surface [Azarhoushang and Kadivar (2022)] Moreover, the mechanical interaction between the abrasive grain and workpiece usually originates compressive residual stresses resulting from localized elastic deformation and plastic flow in fine abrasive finishing, where the chip thickness is minimal. Compressive residual stresses are beneficial to the workpiece’s fatigue life [Cai et al. (2012)]. To reduce the dimensions of space constraints, the machining of the weld bead can be achieved using high cutting speed that affects the surface finish. This allows the residual stresses to be transformed from tensile to compressive values that are more beneficial in reducing fatigue and corrosion of the component [Neto et al. (2022),Chen and Yang (2002)]. . Nomenclature DSS Duplex Stainless Steel RS Residual Stress HAZ Heat Affected Zone FZ Fusion Zone TSR Tensile Residual Stress CRS Compressive Residual Stress HI Heat input BM Base Metal