Underwater wet welding (UWW) is widely used in repair of offshore constructions and underwater pipelines by the shielded metal arc welding (SMAW) method. They are subjected the dynamic load due to sea water flow. In this condition, they can experience the fatigue failure. This study was aimed to determine the effect of water flow speed (0 m/s, 1 m/s, and 2 m/s) and water depth (2.5 m and 5 m) on the crack growth rate of underwater wet welded low carbon steel SS400. Underwater wet welding processes were conducted using E6013 electrode (RB26) with a diameter of 4 mm, type of negative electrode polarity and constant electric current and welding speed of 90 A and 1.5 mm/s respectively. In air welding process was also conducted for comparison. Compared to in air welded joint, underwater wet welded joints have more weld defects including porosity, incomplete penetration and irregular surface. Fatigue crack growth rate of underwater wet welded joints will decrease as water depth increases and water flow rate decreases. It is represented by Paris's constant, where specimens in air welding, 2.5 m and 5 m water depth have average Paris's constant of 8.16, 7.54 and 5.56 respectively. The increasing water depth will cause the formation of Acicular Ferrite structure which has high fatigue crack resistance. The higher the water flow rate, the higher the welding defects, thereby reducing the fatigue crack resistance.
Wet underwater welding is a welding process carried out under water. The depth and water flow velocity greatly affect the welding results. Thus, a further research needs to be done about the effect of the depth and water flow velocity of underwater wet welding. The research aimed to determine the effect of depth and velocity of water flow on underwater wet welding on physical and mechanical properties. The welding process is carried out by using SMAW method at a depth of 2.5 m and 5 m with variations in water flow velocity of 0, 1, and 2 m/s. Land welding is performed as a comparison. X-ray radiography, micro-structure, tensile strength, and Vickers hardness test were performed to determine the type of welding defects. Radiographic test results indicate an incomplete penetration defect (I), spatter (S), porosity (P), undercut (U), concavity (V), and irregular surface (Z). The results of the micro-structure test show that the grain size is fine and coarse as the depth and velocity of the water flow increase. Tensile strength and micro-hardness testing increase along with an increasing depth and velocity of water flow.
Energy consumption in Indonesia every year shows an increasing trend, with energy sources from fossils or non-renewable energy dominating renewable energy in the national energy mix. Climate change due to fossil energy emissions and the depletion of fossil energy reserves directly encourages Indonesia to develop and utilize renewable energy, which is abundantly available in Indonesia. The purpose of this study is to examine the development and planning of the contribution of renewable energy in each sector to the national energy mix in the short to long term. Geothermal capacity total installed in 2019 2130.7 MW with a plan 7.2 GW in 2025 and 17.6 GW in 2050, hydropower total capacity in 2019 6283.3 MW with a paln 21 GW in 2025 and 41 GW in 2050, bioenergy total ini 2019 for power generator 2200 MW with a plan 5.5 GW in 2025 and 26 GW in 2050, in solar energy total capacity in 2020 as power plant 17.22 MW with a plan 6,5 GW in 2025 and 45 GW in 2050, in wind energy until 2020 total capcity for electrical energi 153. 83 MW with a plan 1.8 GW in 2025 and 28 GW in 2050, and the marine energy energy sector in Indonesia has not yet been utilized as an energy harvester. In general, the government targets an increase in the percentage of renewable energy in the national energy mix in the short term until 2025 with a 23% contribution, and in the long term until 2050 with a 31% contribution.
Composites are a combination of two or more different materials with different mechanical properties. The purpose of this research was to determine the effect of the angle orientation of the Boehmeria Nivea fiber-reinforced composite woven on the physical and mechanical properties. Boehmeria Nivea fiber is soaked in an alkaline solution and made into ropes with a diameter of 2-3 mm and then woven with angle orientations of 0o/15o, 0o/30o, 0o/45o and 0o/90o. The composite manufacturing process uses the press molding method. The tests in this study consisted of a tensile test with the ASTM D3039 standard, a flexural test with the ISO 178 standard and a density test with the ASTM C271 standard. Tensile test results show that the highest tensile strength occurs at 0°/15° webbing angle orientation, which is 13.77 Mpa. While the highest bending test results occur at the orientation of the 0°/15° webbing angle, which is 60.52 MPa. Tensile and flexural strength increases with smaller webbing angle orientation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.