Fatigue mechanical behavior of the repair techniques by grinding and wet welding

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Terán, Apolinar Albiter Hernández, Lucila Cruz Castro, S. Capula-Colindres, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3661012/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract This paper presents the results of a fatigue behavior study conducted on standard specimens obtained from a T-welded connection. The techniques of grinding and wet welding, commonly employed in the repair of offshore structures were utilized. The process involved a rectangular grinding in the weld area, followed by the application of wet welding to fill it. Two grinding depths, 6 and 10 mm, were investigated, and tests were performed at three immersion water depths: 50, 70, and 100 m. S-N curves were generated for air exposure conditions and the mentioned immersion depths. The results reveal a decrease in behavior in terms of stress and the number of cycles in the S-N curve as the immersion water depth increases. Particularly low-stress values were observed in connections with a 10 mm grinding depth at water depths of 50, 70, and 100 m. However, in the case of a 6 mm grinding depth and a 50-meter immersion depth, stress values were similar to those under air exposure conditions. This suggests that, in this specific configuration, the combination of grinding and wet welding could be effective in restoring the original service life of T-shaped connections. In contrast, in situations with a 6 mm grinding depth and immersion water depths of 70 and 100 m, significantly lower fatigue results were observed compared to air exposure conditions. T-welded connection grinding wet weld S-N curve A36 steel fatigue behavior wet welding Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 1. Introduction T-welded connections play a crucial role in the construction of fixed platforms in the Gulf of Mexico [ 1 ]. These platforms are exposed to dynamic loads, making regular maintenance essential to either complete or extend their operational lifespan, allowing them to continue oil and gas production in shallow waters [ 2 ]. Consequently, a combination of grinding and wet welding has been adopted to address localized damage at the weld toe of T-welded connections. This approach is favored for its simplicity compared to conventional welding habitats [ 3 ]. Despite various research efforts aimed at enhancing the mechanical properties of weld beads in wet welding processes, several challenges persist. The primary issues revolve around porosity and cracking occurring in the weld pool, resulting in diminished mechanical properties of the wet weld beads. One of the most common defects in the tubular connections of fixed platforms is fatigue-induced cracks. Cracks occur in tubular welded connections, T-connections, etc., where elevated Stress Concentration Factors (SCFs) [ 4 , 5 ], may be present, and in combination with cyclic wave loads, they lead to fatigue cracking. There are multiple repair methods accessible for prolonging the lifespan of steel structures containing cracks [ 6 – 9 ]. One of these methods involves grinding and completely removing the crack. This repair technique has been documented to effectively stop crack propagation. Grinding has been applied with notable success for crack removal in fixed platforms both in the North Sea and the Gulf of Mexico [ 6 , 10 ]. On the other hand, wet welding is a repair technique that has been successfully employed in fixed platforms [ 6 – 9 , 11 ]. Projects for underwater equipment repair have been carried out in the North Sea (trials), as well as underwater pipelines in the Gulf of Mexico. Wet welding has commonly been applied in the repair of structural elements with low Stress Concentration Factors (SCFs) and, therefore, in areas with low susceptibility to fatigue [ 4 , 12 , 13 ] Therefore, one of the major challenges of wet welding is understanding its fatigue behavior [ 8 ]. G. Terán [ 2 , 14 ] reports results from the mechanical characterization of tension tests, hardness, and porosity for a T-joint using a combination of grinding and wet welding. However, one of the needs is to understand the fatigue behavior through the S-N curve when both techniques are combined in T-joint connections. As a continuation of Terán's experimental work, rectangular grinding was performed on the weld toe of a T-joint. The T-welded connections were fabricated with A36 steel. Subsequently, it was filled with wet welding to obtain standard fatigue specimens and determine the S-N curve for different working conditions. 2. Experimental procedure The experimental procedure previously developed by Terán et al. [ 2 , 14 ], was adopted. This procedure involved fabricating the T-shaped connection using dry welding with A36 steel. Table 1 presents the chemical composition of A36 steel. Once the T-shaped connection was completed, a rectangular grinding process was carried out in the weld area, with a width of 4 mm and depths of 6 and 10 mm. Subsequently, this area was filled using wet welding at immersion depths in the sea of 50, 70, and 100 meters, as shown in Fig. 1 . Table 2 provides details on the variables employed in the wet welding process, utilizing E6013 coated electrodes. Table 1 Chemical composition of ASTM A36 Steel [ 2 , 14 ]. Element (%) C Si Mn P S Ni V Cu Nb Al Ti 0.14 0.22 0.76 0.014 0.009 0.01 0.003 0.008 0.002 0.03 0.008 Table 2 Variables used for wet welding [ 2 , 14 ]. Applied current (amperes) Electrode working angle (Degree) Electrode diameter (mm) Water depth (m) 160 60 2.4 and 3.2 50 and 70 190 55 2.4 and 3.2 100 2.1 Procuring Samples for Fatigue Testing Figure 2 shows the specimens and their dimensions obtained from the T-shaped connection, which were prepared for conducting fatigue tests. The machine used for performing these fatigue tests was an MTS, with a capacity of 10 N (equivalent to 10,000 N). These fatigue samples were subjected to a frequency of 26.7 Hz, with sinusoidal cycles and an R = 0 ratio, while maintaining an ambient temperature of 20–23°C in accordance with standards [ 15 , 16 ]. 3. Results and discussion Figure 3 shows the T-shaped connections welded with underwater welding for the three water depths. Table 3 summarizes the results of stress values as a function of the experimental cycle numbers. In accordance with the standard [ 16 ], it is recommended to utilize linear regression when performing fatigue tests and reporting their results. This recommendation is based on the natural variability observed in data when constructing the S-N curve (stress-number of cycles). Table 3 presents the stress values and cycle numbers obtained from experimental tests, complemented by values calculated through linear regression as referenced in [ 17 ]. Figure 4 presents the S-N curve for A36 steel. As evident in Table 3 and Fig. 4 , the stress values calculated through linear regression show a slight increase compared to the experimentally obtained values. Furthermore, they are more consistent and compact. These two observed behaviors result from the application of formulas to adjust stress values to achieve a more consistent slope in the curve. Table 3 Fatigue test data of ASTM A36 steel. Fatigue life, cycles Experimental Regression Stresses (ksi) 63500 50.4 48.2160 46200 50.4 48.3604 44900 50.4 48.3712 20550 49.5 48.5741 162600 47.2 47.3888 180000 47.0 47.2436 55088 46.0 48.2862 228400 44.1 46.8396 360880 42.8 45.7338 1437800 37.8 36.7447 Tables 4 and 5 present the S-N curve results for 6 and 10-mm grinding depths, respectively. Figures 5 and 6 show the fatigue test specimens with 6 mm and 10 mm grinding depths, respectively. Linear regression was not performed in Tables 4 and 5 due to the limited number of values obtained in the fatigue tests. Six specimens were tested for each working condition, while ten tests were conducted in the air condition. Table 4 Fatigue test data of 6 mm grinding depth. 50 m 70 m 100 m Cycles Stresses (ksi) Cycles Stresses (ksi) Cycles Stresses (ksi) 48798 43 10434 39 8423 44 35000 41 15666 36 15088 36 40175 38 27508 31 17398 30 71732 35 68241 28 23291 27 99910 32 60470 25 80064 25 105966 31 68241 23 192644 23 Table 5 Fatigue test data of 10 mm grinding depth. 50m 70 m 100m Cycles Stresses (ksi) Cycles Stresses (ksi) Cycles Stresses (ksi) 8714 30 11055 37 33278 30 9308 27 20145 30 40110 25 14340 25 55030 25 55209 24 30198 23 73173 25 66055 22 49362 19 91074 21 66644 21 67187 15 123930 15 98578 20 As shown in Fig. 7 , depicting the S-N curve for different water depths with a 6 mm grinding depth, stress values are slightly lower at 50 meters compared to A36 steel exposed to air. However, for 70 and 100 meters, stress values are significantly lower than those in air. This trend is attributed to the levels of porosity reported by Terán [ 2 ], which are 2%, 4%, and 8% for depths of 50, 70, and 100 meters, respectively. Additionally, the presence of pores and slag in the wet welding bead contributes to obtaining low stress values and cycle numbers compared to A36 steel exposed to air. Figure 7 shows the bars of the test specimens before the central weld bead is applied, showing a significant increase in porosity and trapped slag in the weld beads. Figure 8 presents the S-N curve for a grinding depth of 10 mm. It is evident that the values for the three immersion water depths (50, 70, and 100 meters) are considerably lower compared to A36 steel tested in air conditions. Furthermore, for 50-meter condition the lowest values of stress and number of cycles among the three immersion depths was observed. These reduced values of stress and number of cycles are attributed to the presence of more pronounced porosity and slag in the bars used in fatigue tests. In the most critical condition, at a depth of 100 meters and with a grinding depth of 10 mm, porosity and slag in the wet welding bead area are practically being evaluated in the marine environment. Additionally, for a grinding depth of 10 mm and at 50, 70, and 100 meters of immersion, the porosity levels of 3%, 5%, and 10% are obtained, respectively. This results in obtaining reduced values of stress and the number of cycles in fatigue tests. Figure 9 shows the fracture areas in the test specimens after subjecting them to fatigue. As mentioned earlier, the lowest stress and cycle number values are obtained for the condition with a 10 mm grinding depth and a 50-meter water depth, compared to the other conditions. These values result from the presence of pores and slag that occupied a significant portion of the cross-sectional area in the fracture zone of the test specimens. For the condition with a 6 mm grinding depth and 50 meters of immersion, an elongated pore and trapped slag are also observed. In the other conditions, elongated pores and slag are also noticeable. The abundance of pores and slag in the working area of the fatigue test specimens leads to a dispersion of stress values in the S-N curve, as described in Figs. 7 and 8 . Given the restricted number of fatigue test specimens and the notable dispersion of stress values, linear regressions were omitted for each working condition. Based on the presented analysis, we can conclude that the condition of 6 mm grinding depth and 50 m underwater depth could enhance fatigue resistance in T-connections. This conclusion is drawn from the stress values and the number of cycles, which closely align with conditions in the air. Another factor supporting this assertion is the limitations of fatigue test specimens. Occasionally, pores and/or slag can occupy a significant portion of the test specimens' surface area, resulting in a considerable dispersion in stress values and cycle numbers used to construct the S-N curve. When a pore and/or slag occupies a substantial portion of the fatigue test specimen's area, the true influence of the combination of grinding and wet welding is not accurately assessed. Another significant consideration is the difficulty in establishing the fatigue limit for working conditions due to the percentage of porosity present in the fatigue test specimens. As described earlier, porosity is distributed throughout all the fatigue test specimens. Pessoa reports [18, 19, 20, 21] that porosity decreases along welds, and mechanical properties such as tensile strength and ductility of test specimens are higher at the end of the bead for A36 steel V-groove plates welded with E6013 coated electrodes at depths of 50 and 100 m, as showed in Fig. 10 . The reduction in porosity is attributed to the fact that at the beginning of the bead deposition using E6013 electrodes on A36 steel, short circuits (globular and short-circuit modes) occur, leading to elevated levels of porosity. This change in bead deposition is due to low voltage values to initiate the arc and low electrode heat, resulting in slow fusion speed and the formation of droplets in the bead, which, these droplets trap a higher number of gases (H 2 , CO, and CO 2 ) [22]. The trapped gases, shown in Fig. 11 , become concentrated along the weld bead, and crack propagation can initiate within them. Hydrogen cracking reduces ductility and toughness in wet welding [23]. Additionally, factors such as moisture present at the electrode tip (moisture absorption at the electrode tip), the start-up of power by the welding machine (power source start-up), and electrode heating contribute to this phenomenon, as noted by Peréz et al. [24]. Hence, we suggest that for a comprehensive analysis and obtain the S-N curve for each working condition, fatigue test specimens should be obtained from the central region of the weld bead within a wet environment. This approach ensures the attainment of more precise stress values and a greater number of cycles before failure. When evaluating fatigue behavior in situations involving wet welding repairs on structural connections or any component, it is recommended to examine the entire connection or structure. This approach ensures an accurate representation of the actual mechanical behavior of the structure under fatigue. However, it's essential to acknowledge the limitations, only a few laboratories have the capability to conduct fatigue analysis on full-scale connections due to the involved loads and associated economic costs. In cases where evaluating the entire structural connection is not feasible, S-N testing may serve as a viable option to comprehend the behavior of wet welding repairs. 4. Conclusion The fatigue life of T connections could be improved by combining grinding and welding, particularly with a grinding depth of 6 mm and a water depth of 50 meters. However, for other grinding conditions and water depths, low values of stress and cycle numbers were obtained due to the presence of pores and/or slag in the working area of the fatigue specimen. Identifying and controlling porosity in the reduced section of the specimen is crucial, as wet welding could result in scattered stress values and low cycle numbers. Therefore, it is recommended to obtain fatigue specimens from the middle of the weld beads, where the porosity is typically lower. To evaluate the fatigue behavior of connections subjected to grinding and wet welding, a comprehensive assessment is suggested, considering the capabilities of the equipment and associated costs. Declarations Acknowledgments The authors would like to express their gratitude to the Dirección de Investigación y Posgrado del Instituto Mexicano del Petróleo and CONACYT for support in this research work. Special thanks to the Mechanical Test Laboratory of Instituto Nacional de Investigaciones Nucleates (ININ) for providing the facilities to conduct fatigue tests. Roberto Carlos González Díaz for his support during the fatigue tests, and to the Federal University of Mines Gerais in Brazil for allowing the use of their laboratory for the wet welding process. 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Caires Pereira Pessoa E, Bracarense A, Liu S, Pérez-Guerrero F (2003) Study of Porosity Location in Fresh Water Wet Welds Pessoa ECP, Bracarense AQ, Zica EM, et al (2006) Porosity variation along multipass underwater wet welds and its influence on mechanical properties. J Mater Process Technol 179:239–243. https://doi.org/https://doi.org/10.1016/j.jmatprotec.2006.03.071 Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3661012","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":267427944,"identity":"0f0817e1-5b6b-4143-9ace-49fb04361cb0","order_by":0,"name":"G. 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1","display":"","copyAsset":false,"role":"figure","size":264090,"visible":true,"origin":"","legend":"\u003cp\u003eT-welded connection: a) real image, and b) schematic representation of T-welded connection filled by wet welding, units in mm.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-3661012/v1/477bdefe168aee052df15fd5.png"},{"id":49825138,"identity":"27ebde2d-4942-4ce7-aaf4-bbba44e1bfd9","added_by":"auto","created_at":"2024-01-18 15:43:02","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":471480,"visible":true,"origin":"","legend":"\u003cp\u003eFatigue specimens: a) schematic representation of T-welded connection, and b) real image specimens for 6 mm grinding depth and 50 m water 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radius: a) 50 m and 6 mm de grinding depth, and b) 100 m and 10 mm grinding depth.\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-3661012/v1/03c22fb9a4ca287d989a70f0.png"},{"id":49827604,"identity":"b97756a7-3547-473d-9b0e-eb5f2ed9896d","added_by":"auto","created_at":"2024-01-18 15:59:02","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":55629,"visible":true,"origin":"","legend":"\u003cp\u003eS-N diagram for 6 mm grinding depth.\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-3661012/v1/5bfe742288923274b6842d66.png"},{"id":49826427,"identity":"9e643399-5b69-47ac-a02a-074db70795dc","added_by":"auto","created_at":"2024-01-18 15:51:02","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":72564,"visible":true,"origin":"","legend":"\u003cp\u003eS-N diagram for 10 mm grinding depth.\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-3661012/v1/afdf4e5757a42810b774a7f2.png"},{"id":49825146,"identity":"04f5c237-212b-4b90-9bc5-049f58a17273","added_by":"auto","created_at":"2024-01-18 15:43:02","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":1367022,"visible":true,"origin":"","legend":"\u003cp\u003eFracture fatigue specimens as a function of depth and grinding.\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-3661012/v1/99861ac22e14fa85413c4268.png"},{"id":49825145,"identity":"0f2a977f-41d1-41c0-96ed-fed13916cfaf","added_by":"auto","created_at":"2024-01-18 15:43:02","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":758146,"visible":true,"origin":"","legend":"\u003cp\u003eWeld bead photo and radiograph of electrode E6013, A-36 steel at: a) 50 m and b) 100 m depth [19]\u003cstrong\u003e.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-3661012/v1/3e1e3e858d0d62e050674064.png"},{"id":49825149,"identity":"04fe84b0-5db0-4c80-8c30-72ffa2e790ad","added_by":"auto","created_at":"2024-01-18 15:43:02","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":901334,"visible":true,"origin":"","legend":"\u003cp\u003ePorosity along the weld bead: a) schematic representation of trapped porosity, and b) T-connection showing the pores.\u003c/p\u003e","description":"","filename":"11.png","url":"https://assets-eu.researchsquare.com/files/rs-3661012/v1/6105bcb9afe89c3e3333a2e1.png"},{"id":56242733,"identity":"828fd026-d6c5-4162-b929-834ea0da9a51","added_by":"auto","created_at":"2024-05-10 10:17:03","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":5910783,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3661012/v1/9d4ecf43-a718-4029-83fc-25e85c97eae6.pdf"}],"financialInterests":"","formattedTitle":"Fatigue mechanical behavior of the repair techniques by grinding and wet welding","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eT-welded connections play a crucial role in the construction of fixed platforms in the Gulf of Mexico [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. These platforms are exposed to dynamic loads, making regular maintenance essential to either complete or extend their operational lifespan, allowing them to continue oil and gas production in shallow waters [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Consequently, a combination of grinding and wet welding has been adopted to address localized damage at the weld toe of T-welded connections. This approach is favored for its simplicity compared to conventional welding habitats [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Despite various research efforts aimed at enhancing the mechanical properties of weld beads in wet welding processes, several challenges persist. The primary issues revolve around porosity and cracking occurring in the weld pool, resulting in diminished mechanical properties of the wet weld beads.\u003c/p\u003e \u003cp\u003eOne of the most common defects in the tubular connections of fixed platforms is fatigue-induced cracks. Cracks occur in tubular welded connections, T-connections, etc., where elevated Stress Concentration Factors (SCFs) [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], may be present, and in combination with cyclic wave loads, they lead to fatigue cracking.\u003c/p\u003e \u003cp\u003eThere are multiple repair methods accessible for prolonging the lifespan of steel structures containing cracks [\u003cspan additionalcitationids=\"CR7 CR8\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. One of these methods involves grinding and completely removing the crack. This repair technique has been documented to effectively stop crack propagation. Grinding has been applied with notable success for crack removal in fixed platforms both in the North Sea and the Gulf of Mexico [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eOn the other hand, wet welding is a repair technique that has been successfully employed in fixed platforms [\u003cspan additionalcitationids=\"CR7 CR8\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Projects for underwater equipment repair have been carried out in the North Sea (trials), as well as underwater pipelines in the Gulf of Mexico. Wet welding has commonly been applied in the repair of structural elements with low Stress Concentration Factors (SCFs) and, therefore, in areas with low susceptibility to fatigue [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] Therefore, one of the major challenges of wet welding is understanding its fatigue behavior [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eG. Ter\u0026aacute;n [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] reports results from the mechanical characterization of tension tests, hardness, and porosity for a T-joint using a combination of grinding and wet welding. However, one of the needs is to understand the fatigue behavior through the S-N curve when both techniques are combined in T-joint connections. As a continuation of Ter\u0026aacute;n's experimental work, rectangular grinding was performed on the weld toe of a T-joint. The T-welded connections were fabricated with A36 steel. Subsequently, it was filled with wet welding to obtain standard fatigue specimens and determine the S-N curve for different working conditions.\u003c/p\u003e"},{"header":"2. Experimental procedure","content":"\u003cp\u003eThe experimental procedure previously developed by Ter\u0026aacute;n et al. [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e], was adopted. This procedure involved fabricating the T-shaped connection using dry welding with A36 steel. Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e presents the chemical composition of A36 steel. Once the T-shaped connection was completed, a rectangular grinding process was carried out in the weld area, with a width of 4 mm and depths of 6 and 10 mm. Subsequently, this area was filled using wet welding at immersion depths in the sea of 50, 70, and 100 meters, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e provides details on the variables employed in the wet welding process, utilizing E6013 coated electrodes.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eChemical composition of ASTM A36 Steel [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"11\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"11\" nameend=\"c11\" namest=\"c1\"\u003e \u003cp\u003eElement (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMn\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eV\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eCu\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNb\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eAl\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003eTi\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.014\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.009\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.003\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.008\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.002\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e0.008\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eVariables used for wet welding [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eApplied current\u003c/p\u003e \u003cp\u003e(amperes)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eElectrode working angle\u003c/p\u003e \u003cp\u003e(Degree)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eElectrode diameter\u003c/p\u003e \u003cp\u003e(mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eWater depth\u003c/p\u003e \u003cp\u003e(m)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e160\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.4 and 3.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e50 and 70\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e190\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.4 and 3.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Procuring Samples for Fatigue Testing\u003c/h2\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows the specimens and their dimensions obtained from the T-shaped connection, which were prepared for conducting fatigue tests. The machine used for performing these fatigue tests was an MTS, with a capacity of 10 N (equivalent to 10,000 N). These fatigue samples were subjected to a frequency of 26.7 Hz, with sinusoidal cycles and an R\u0026thinsp;=\u0026thinsp;0 ratio, while maintaining an ambient temperature of 20\u0026ndash;23\u0026deg;C in accordance with standards [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results and discussion","content":"\u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows the T-shaped connections welded with underwater welding for the three water depths. Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e summarizes the results of stress values as a function of the experimental cycle numbers.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn accordance with the standard [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], it is recommended to utilize linear regression when performing fatigue tests and reporting their results. This recommendation is based on the natural variability observed in data when constructing the S-N curve (stress-number of cycles). Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e presents the stress values and cycle numbers obtained from experimental tests, complemented by values calculated through linear regression as referenced in [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e presents the S-N curve for A36 steel. As evident in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e, the stress values calculated through linear regression show a slight increase compared to the experimentally obtained values. Furthermore, they are more consistent and compact. These two observed behaviors result from the application of formulas to adjust stress values to achieve a more consistent slope in the curve.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eFatigue test data of ASTM A36 steel.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eFatigue life, cycles\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eExperimental\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRegression\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eStresses (ksi)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e63500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e50.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e48.2160\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e46200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e50.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e48.3604\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e44900\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e50.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e48.3712\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e20550\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e49.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e48.5741\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e162600\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e47.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e47.3888\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e180000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e47.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e47.2436\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e55088\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e46.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e48.2862\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e228400\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e44.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e46.8396\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e360880\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e42.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e45.7338\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1437800\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e37.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e36.7447\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eTables\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e and \u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e present the S-N curve results for 6 and 10-mm grinding depths, respectively. Figures\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e and \u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e show the fatigue test specimens with 6 mm and 10 mm grinding depths, respectively. Linear regression was not performed in Tables\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e and \u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e due to the limited number of values obtained in the fatigue tests. Six specimens were tested for each working condition, while ten tests were conducted in the air condition.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eFatigue test data of 6 mm grinding depth.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e50 m\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e70 m\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e100 m\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCycles\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eStresses\u003c/p\u003e \u003cp\u003e(ksi)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCycles\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eStresses\u003c/p\u003e \u003cp\u003e(ksi)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCycles\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eStresses\u003c/p\u003e \u003cp\u003e(ksi)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e48798\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10434\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8423\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e44\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e35000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e15666\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e15088\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e40175\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e27508\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e17398\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e71732\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e68241\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e23291\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e99910\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e60470\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e80064\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e105966\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e68241\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e192644\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eFatigue test data of 10 mm grinding depth.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e50m\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e70 m\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e100m\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCycles\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eStresses\u003c/p\u003e \u003cp\u003e(ksi)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCycles\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eStresses\u003c/p\u003e \u003cp\u003e(ksi)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCycles\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eStresses\u003c/p\u003e \u003cp\u003e(ksi)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e8714\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11055\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e33278\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e9308\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e20145\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e40110\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e14340\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e55030\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e55209\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e24\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e30198\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e73173\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e66055\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e49362\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e91074\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e66644\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e67187\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e123930\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e98578\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eAs shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e, depicting the S-N curve for different water depths with a 6 mm grinding depth, stress values are slightly lower at 50 meters compared to A36 steel exposed to air. However, for 70 and 100 meters, stress values are significantly lower than those in air. This trend is attributed to the levels of porosity reported by Ter\u0026aacute;n [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], which are 2%, 4%, and 8% for depths of 50, 70, and 100 meters, respectively. Additionally, the presence of pores and slag in the wet welding bead contributes to obtaining low stress values and cycle numbers compared to A36 steel exposed to air. Figure\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e shows the bars of the test specimens before the central weld bead is applied, showing a significant increase in porosity and trapped slag in the weld beads.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e presents the S-N curve for a grinding depth of 10 mm. It is evident that the values for the three immersion water depths (50, 70, and 100 meters) are considerably lower compared to A36 steel tested in air conditions. Furthermore, for 50-meter condition the lowest values of stress and number of cycles among the three immersion depths was observed. These reduced values of stress and number of cycles are attributed to the presence of more pronounced porosity and slag in the bars used in fatigue tests.\u003c/p\u003e \u003cp\u003eIn the most critical condition, at a depth of 100 meters and with a grinding depth of 10 mm, porosity and slag in the wet welding bead area are practically being evaluated in the marine environment. Additionally, for a grinding depth of 10 mm and at 50, 70, and 100 meters of immersion, the porosity levels of 3%, 5%, and 10% are obtained, respectively. This results in obtaining reduced values of stress and the number of cycles in fatigue tests.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e shows the fracture areas in the test specimens after subjecting them to fatigue. As mentioned earlier, the lowest stress and cycle number values are obtained for the condition with a 10 mm grinding depth and a 50-meter water depth, compared to the other conditions. These values result from the presence of pores and slag that occupied a significant portion of the cross-sectional area in the fracture zone of the test specimens. For the condition with a 6 mm grinding depth and 50 meters of immersion, an elongated pore and trapped slag are also observed. In the other conditions, elongated pores and slag are also noticeable. The abundance of pores and slag in the working area of the fatigue test specimens leads to a dispersion of stress values in the S-N curve, as described in Figs.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e and \u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eGiven the restricted number of fatigue test specimens and the notable dispersion of stress values, linear regressions were omitted for each working condition.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eBased on the presented analysis, we can conclude that the condition of 6 mm grinding depth and 50 m underwater depth could enhance fatigue resistance in T-connections. This conclusion is drawn from the stress values and the number of cycles, which closely align with conditions in the air. Another factor supporting this assertion is the limitations of fatigue test specimens. Occasionally, pores and/or slag can occupy a significant portion of the test specimens' surface area, resulting in a considerable dispersion in stress values and cycle numbers used to construct the S-N curve. When a pore and/or slag occupies a substantial portion of the fatigue test specimen's area, the true influence of the combination of grinding and wet welding is not accurately assessed. Another significant consideration is the difficulty in establishing the fatigue limit for working conditions due to the percentage of porosity present in the fatigue test specimens. As described earlier, porosity is distributed throughout all the fatigue test specimens.\u003c/p\u003e \u003cp\u003ePessoa reports [18, 19, 20, 21] that porosity decreases along welds, and mechanical properties such as tensile strength and ductility of test specimens are higher at the end of the bead for A36 steel V-groove plates welded with E6013 coated electrodes at depths of 50 and 100 m, as showed in Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e. The reduction in porosity is attributed to the fact that at the beginning of the bead deposition using E6013 electrodes on A36 steel, short circuits (globular and short-circuit modes) occur, leading to elevated levels of porosity.\u003c/p\u003e \u003cp\u003eThis change in bead deposition is due to low voltage values to initiate the arc and low electrode heat, resulting in slow fusion speed and the formation of droplets in the bead, which, these droplets trap a higher number of gases (H\u003csub\u003e2\u003c/sub\u003e, CO, and CO\u003csub\u003e2\u003c/sub\u003e) [22]. The trapped gases, shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e, become concentrated along the weld bead, and crack propagation can initiate within them. Hydrogen cracking reduces ductility and toughness in wet welding [23]. Additionally, factors such as moisture present at the electrode tip (moisture absorption at the electrode tip), the start-up of power by the welding machine (power source start-up), and electrode heating contribute to this phenomenon, as noted by Per\u0026eacute;z et al. [24].\u003c/p\u003e \u003cp\u003eHence, we suggest that for a comprehensive analysis and obtain the S-N curve for each working condition, fatigue test specimens should be obtained from the central region of the weld bead within a wet environment. This approach ensures the attainment of more precise stress values and a greater number of cycles before failure. When evaluating fatigue behavior in situations involving wet welding repairs on structural connections or any component, it is recommended to examine the entire connection or structure. This approach ensures an accurate representation of the actual mechanical behavior of the structure under fatigue.\u003c/p\u003e \u003cp\u003eHowever, it's essential to acknowledge the limitations, only a few laboratories have the capability to conduct fatigue analysis on full-scale connections due to the involved loads and associated economic costs. In cases where evaluating the entire structural connection is not feasible, S-N testing may serve as a viable option to comprehend the behavior of wet welding repairs.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eThe fatigue life of T connections could be improved by combining grinding and welding, particularly with a grinding depth of 6 mm and a water depth of 50 meters. However, for other grinding conditions and water depths, low values of stress and cycle numbers were obtained due to the presence of pores and/or slag in the working area of the fatigue specimen. Identifying and controlling porosity in the reduced section of the specimen is crucial, as wet welding could result in scattered stress values and low cycle numbers.\u003c/p\u003e \u003cp\u003eTherefore, it is recommended to obtain fatigue specimens from the middle of the weld beads, where the porosity is typically lower. To evaluate the fatigue behavior of connections subjected to grinding and wet welding, a comprehensive assessment is suggested, considering the capabilities of the equipment and associated costs.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAcknowledgments\u003c/h2\u003e \u003cp\u003eThe authors would like to express their gratitude to the Direcci\u0026oacute;n de Investigaci\u0026oacute;n y Posgrado del Instituto Mexicano del Petr\u0026oacute;leo and CONACYT for support in this research work. Special thanks to the Mechanical Test Laboratory of Instituto Nacional de Investigaciones Nucleates (ININ) for providing the facilities to conduct fatigue tests. Roberto Carlos Gonz\u0026aacute;lez D\u0026iacute;az for his support during the fatigue tests, and to the Federal University of Mines Gerais in Brazil for allowing the use of their laboratory for the wet welding process.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eTer\u0026aacute;n G, Capula-Colindres S, Melendez R, et al (2015) 3-D Porosity in T-Welded Connections Repaired by Grinding and Wet Welding. 25\u0026ndash;32. https://doi.org/10.1007/978-3-319-15204-2_3\u003c/li\u003e\n\u003cli\u003eTer\u0026aacute;n G, Cuamatzi-Mel\u0026eacute;ndez R, Albiter A, et al (2014) Characterization of the mechanical properties and structural integrity of T-welded connections repaired by grinding and wet welding. Mater Sci Eng A 599:105\u0026ndash;115. https://doi.org/https://doi.org/10.1016/j.msea.2014.01.078\u003c/li\u003e\n\u003cli\u003ePadilla E, Silva L, Santos V, Paciornik S (2013) Image analysis of cracks in the weld metal of a wet welded steel joint by three dimensional (3D) X-ray microtomography. Mater Charact 83:139\u0026ndash;144. https://doi.org/10.1016/j.matchar.2013.06.016\u003c/li\u003e\n\u003cli\u003eTer\u0026aacute;n G, Albiter A, Cuamatzi-Mel\u0026eacute;ndez R (2013) Parametric evaluation of the stress concentration factors in T-butt welded connections. Eng Struct 56:1484\u0026ndash;1495. https://doi.org/https://doi.org/10.1016/j.engstruct.2013.06.031\u003c/li\u003e\n\u003cli\u003eTer\u0026aacute;n, G., Albiter, A. Cuamatzi-Mel\u0026eacute;ndez, R. JM-CALM-A (2014) The stress concentration factors of a T-welded connection, varying grinding profiles and depths. Part I. Finite element modeling and experimental work. Under review.\u003c/li\u003e\n\u003cli\u003eBraun M, Wang X (2021) A review of fatigue test data on weld toe grinding and weld profiling. Int J Fatigue 145:106073. https://doi.org/https://doi.org/10.1016/j.ijfatigue.2020.106073\u003c/li\u003e\n\u003cli\u003eDehghani A, Aslani F (2019) A review on defects in steel offshore structures and developed strengthening techniques. Structures 20:635\u0026ndash;657. https://doi.org/https://doi.org/10.1016/j.istruc.2019.06.002\u003c/li\u003e\n\u003cli\u003eSteimbreger C, Gubeljak N, Vuherer T, et al (2022) Effect of welding processes on the fatigue behaviour of ultra-high strength steel butt-welded joints. Eng Fract Mech 275:108845. https://doi.org/https://doi.org/10.1016/j.engfracmech.2022.108845\u003c/li\u003e\n\u003cli\u003eMay P, Sanderson D, Sharp J V, Stacey A (2008) Structural Integrity Monitoring: Review and Appraisal of Current Technologies for Offshore Applications\u003c/li\u003e\n\u003cli\u003eGao W, Wang D, Cheng F, et al (2015) Enhancement of the fatigue strength of underwater wet welds by grinding and ultrasonic impact treatment. J Mater Process Technol 223:305\u0026ndash;312. https://doi.org/https://doi.org/10.1016/j.jmatprotec.2015.04.013\u003c/li\u003e\n\u003cli\u003eZhang M, Han Y, Jia C, et al (2021) Process Stability, Microstructure and Mechanical Properties of Underwater Submerged-Arc Welded Steel. Metals (Basel). 11\u003c/li\u003e\n\u003cli\u003eAl-Karawi H, von Bock und Polach RUF, Al-Emrani M (2021) Fatigue life extension of existing welded structures via high frequency mechanical impact (HFMI) treatment. Eng Struct 239:112234. https://doi.org/https://doi.org/10.1016/j.engstruct.2021.112234\u003c/li\u003e\n\u003cli\u003eZhao P, Yu B, Wang P, et al (2023) Influence of Repair Welding on the Fatigue Behavior of S355J2 T-Joints. Materials (Basel) 16:. https://doi.org/10.3390/ma16103682\u003c/li\u003e\n\u003cli\u003eM\u0026eacute;ndez GT, Cuamatzi-Mel\u0026eacute;ndez R, Hern\u0026aacute;ndez AA (2014) Combination of Grinding and Wet Welding to Repair Localized Cracking in T-Welded Connections. Mater Sci Forum 793:51\u0026ndash;58. https://doi.org/10.4028/www.scientific.net/MSF.793.51\u003c/li\u003e\n\u003cli\u003eInternational A ASTM E 466-07, Standard Practice for Controlled Constant Amplitude Axial Fatigue Test of Metallic Materials\u003c/li\u003e\n\u003cli\u003eASTM International ASTM E468-90, Standard Practice for Presentation of Constant Amplitude Fatigue Test Results for Metallic Materials.\u003c/li\u003e\n\u003cli\u003eMurray R. Spiegel and JL (1999) Mathematical handbook of formulas and tables.\u003c/li\u003e\n\u003cli\u003eCaires Pereira Pessoa E, Bracarense A, Liu S, P\u0026eacute;rez-Guerrero F (2003) Study of Porosity Location in Fresh Water Wet Welds\u003c/li\u003e\n\u003cli\u003ePessoa ECP, Bracarense AQ, Zica EM, et al (2006) Porosity variation along multipass underwater wet welds and its influence on mechanical properties. J Mater Process Technol 179:239\u0026ndash;243. https://doi.org/https://doi.org/10.1016/j.jmatprotec.2006.03.071\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"T-welded connection, grinding, wet weld, S-N curve, A36 steel, fatigue behavior, wet welding","lastPublishedDoi":"10.21203/rs.3.rs-3661012/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3661012/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis paper presents the results of a fatigue behavior study conducted on standard specimens obtained from a T-welded connection. The techniques of grinding and wet welding, commonly employed in the repair of offshore structures were utilized. The process involved a rectangular grinding in the weld area, followed by the application of wet welding to fill it. Two grinding depths, 6 and 10 mm, were investigated, and tests were performed at three immersion water depths: 50, 70, and 100 m. S-N curves were generated for air exposure conditions and the mentioned immersion depths. The results reveal a decrease in behavior in terms of stress and the number of cycles in the S-N curve as the immersion water depth increases. Particularly low-stress values were observed in connections with a 10 mm grinding depth at water depths of 50, 70, and 100 m. However, in the case of a 6 mm grinding depth and a 50-meter immersion depth, stress values were similar to those under air exposure conditions. This suggests that, in this specific configuration, the combination of grinding and wet welding could be effective in restoring the original service life of T-shaped connections. In contrast, in situations with a 6 mm grinding depth and immersion water depths of 70 and 100 m, significantly lower fatigue results were observed compared to air exposure conditions.\u003c/p\u003e","manuscriptTitle":"Fatigue mechanical behavior of the repair techniques by grinding and wet welding","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-01-18 15:42:57","doi":"10.21203/rs.3.rs-3661012/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"83a4b6a4-8a15-488b-84da-4a9eac144f3d","owner":[],"postedDate":"January 18th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-05-10T10:08:53+00:00","versionOfRecord":[],"versionCreatedAt":"2024-01-18 15:42:57","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-3661012","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3661012","identity":"rs-3661012","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}