Dissertations / Theses on the topic 'Welding underwater'
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Clukey, David Alan. "Evaluation and Analysis of Underwater "Wet" Welding Process." The Ohio State University, 1999. http://rave.ohiolink.edu/etdc/view?acc_num=osu1391793136.
Full textCave, W. R. "Investigation of the constricted plasma arc process for hyperbaric welding at pressures 1 to 100bar." Thesis, Cranfield University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360220.
Full textWu, Ji. "Profile monitoring and object recognition using image processing." Thesis, University of Leicester, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240882.
Full textOverfield, Norman E. "Feasibility of underwater friction stir welding of hardenable alloy steel." Thesis, Monterey, California. Naval Postgraduate School, 2010. http://hdl.handle.net/10945/5092.
Full textThe objective of this thesis is to determine whether friction stir welding (FSW) is a feasible welding process for steels in an underwater environment. Specific benefits would be underwater weld repairs on steel alloy piping systems and/or structures, and crack repairs on control surfaces of submarines without the need for strict environment controls or in the submarine's case, for drydocking. A single tool made of polycrystaline cubic boron nitride (PCBN) with a Tungsten-Rhenium binder was used to conduct a series of bead-on-plate FSW traverses, approximately 64 inches (1.6 m) in total length, on 0.25 inch (6.4 mm) thick plates of a hardenable alloy steel. The first series of traverses involved various revolutions per minute (RPM) and inches per minute (IPM) combinations on a dry plate. A second series was conducted while a plate was immersed in water in order to assess the potential for inducing hydrogen assisted cracking (HAC) during FSW of susceptible alloys. All traverses were visually defect-free. The FSW nuggets (stir zone) exhibited refined microstructures and increased hardness relative to the base plate. Based on preliminary findings, FSW of hardenable alloy steel is a feasible process and should be further researched and refined.
Stewart, William Chad. "Feasibility of underwater friction stir welding of HY-80 steel." Thesis, Monterey, California. Naval Postgraduate School, 2011. http://hdl.handle.net/10945/5741.
Full textThe purpose of this thesis is to determine the feasibility of underwater friction stir welding (FSW) of high-strength; quench and temper low carbon steels that are susceptible to hydrogen-assisted cracking (HAC). The specific benefits of underwater FSW would be weld repairs of ship and submarine control surfaces and hulls without the need for drydocking and extensive environmental control procedures. A single tool of polycrystalline cubic boron nitride (PCBN) in a Tungsten-Rhenium binder was used to conduct three bead-on-plate FSW traverses, approximately 40 inches in length on 0.25 inch HY-80 steel. The first traverse was a dry weld and the second and third traverse were wet (underwater) welds, all conducted at a combination of 400 revolutions per minute and 2 inches per minute. The wet welds were conducted for the purpose of assessing the HAC susceptibility of the process.
Gnatetski, Viatcheslav. "Mechanical design and development of an automatic orbital welding system ("Halo")." Available from the University of Aberdeen Library and Historic Collections Digital Resources. Restricted: no access until Oct., 28, 2010, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=69375.
Full textCullen, Shawn. "Development of a Human and Organizational Factors (HOF) Annex for underwater welding." Thesis, Monterey, California. Naval Postgraduate School, 1997. http://hdl.handle.net/10945/8258.
Full textRecent improvements in underwater welding have led to the increased use of wet and dry hyperbaric welding within the marine construction industry. The general acceptance of underwater welding processes has been further advanced by the standardization of methods, procedures, and certification requirements provided by the American National Standards Institute (ANSI)/American Welding Society (AWS) D3.6 Specification for Underwater Welding. A dedicated effort has been made by the AWS D3B Subcommittee on Underwater Welding to pursue all available means to improve the levels of productivity and safety across the underwater welding industry. One approach which has become a priority of the committee is the inclusion of Human and Organizational Factors considerations within the Specifications in the form of an HOF supplementary annex. This paper provides a brief summation of HOF principles, a methodology for developing an HOF Annex for underwater welding, recommended content and structure for such an annex, and a combined qualitative and quantitative procedure for determining the utility of recommended HOF improvement applications
LEAO, ANA PAULA BECK. "NI ALLOYED WELD METALS WITH ADDITIONS OF CU AND MO FOR UNDERWATER WET WELDING." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2009. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=15335@1.
Full textThis work was carried out to improve the mechanical properties of weld metals deposited by nickel oxidizing electrodes, together with additions of copper and molybdenum, through the grain refinement or by solid solution hardening. The oxidizing electrodes are characterized by the lower levels of diffusible hydrogen and, hence, by the lesser possibility of cold crack formation when compared to rutile electrodes. However, the weld metal deposited with this type of electrode shows mechanical properties below that obtained by rutile electrodes, as long as important alloy elements, such as Mn and Si, are lost by oxidation. In order to avoid this situation and obtain weld metals with better mechanical properties it was added alloy elements that are not significantly affected by the oxidant character of the coating, such as Cu and Mo. Two test specimens were prepared for welding, where spaced holes and a notch were machined in each one for the addition of both elements, Cu and Mo. Different percentages of these elements were measured by Energy Dispersive Spectroscopy microanalysis. From these results it was performed microstructural analysis using optical microscopy, grain size measurements and microhardness tests to evaluate the influence of each element in the weld metal and compare them to each other. The results showed that molybdenum has a stronger influence on the microhardness of the weld metal than copper. Regarding the grain size it was noted an opposite influence of the elements, where the addition of Mo caused a decrease of the grain size and the addition of Cu caused a slightly increase, until the grain size becomes constant.
Moision, William Charles. "Underwater Welding of Mild Steel: A Study of the Effects of Welding variables on Weld Quality Using the Open Arc Flux Cored Process." The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1393072985.
Full textITOH, Y., Y. KITANE, and X. CHEN. "Compression Behaviors of Thickness-Reduced Steel Pipes Repaired with Underwater Welds." Elsevier, 2011. http://hdl.handle.net/2237/18823.
Full textItoh, Yoshito, Yasuo Kitane, and Xiao Chen. "Mechanical Properties of Fillet Weld Joints by Underwater Wet Welding in Repairing Corrosion-Damaged Offshore Steel Structures." 土木学会, 2010. http://hdl.handle.net/2237/18845.
Full textSheakley, Brian J. "Effect of water depth on the underwater wet welding of ferritic steels using austenitic Ni-based alloy electrodes." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2000. http://handle.dtic.mil/100.2/ADA384061.
Full textFERREIRA, FREDY AUGUSTO FUENTES. "EVALUATION OF THE EFFECTS OF REPLACEMENT OF HEMATITE BY WUSTITE ON OXIDIZING ELECTRODES COATING FOR UNDERWATER WET WELDING." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2009. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=15408@1.
Full textA soldagem subaquática molhada é uma das técnicas utilizadas no reparo de plataformas submarinas para extração de petróleo e gás, tendo uma grande expansão no mundo atual. Sua maior vantagem frente a outros processos de soldagem se deve a sua simplicidade e facilidade de mobilização, já que permite ao mergulhador trabalhar diretamente sobre as partes submersas das peças sem a proteção de um ambiente artificial, como na tradicional solda a seco. Neste tipo de soldagem são usados tanto eletrodos oxidantes quanto eletrodos rutílicos. Neste trabalho busca-se avaliar os efeitos da utilização de Wustita em substituição parcial à Hematita, mineral empregado no revestimento de eletrodos oxidantes. Foram produzidos 5 grupos de eletrodos mantendo fixa a porcentagem em peso do total de óxidos de ferro e variando as proporções de FeO e Fe2O3. Realizaram-se soldas de 4 passes em posição plana com ângulo de 60º de inclinação entre o eletrodo e a chapa a 0.5m de profundidade. Os metais soldados foram avaliados por análise química, microscopia, hidrogênio difusível e micro dureza. Desenvolveram-se métodos de análise digital de imagens, para medir fração de área de inclusões a partir de imagens de MO e MEV, e a fração de microconstituintes por MO. Os resultados mostraram um aumento de ferrita próeutetóide com o aumento da wustita e uma diminuição com a fração de carbono. Esta, por sua vez, decresceu com o aumento da wustita. A micro-dureza decresceu com a fração de wustita e cresceu com a fração de carbono.
Underwater wet welding is one of the techniques used in the repair of underwater oil and gas platforms, with a large expansion in the world nowadays. Its major advantage over other welding processes is due to its simplicity and ease of deployment, as it allows the diver to work directly on the submerged portions of the parts without the protection of an artificial environment, as in the traditional dry welding. Both oxidizing and rutilic electrodes are used in this type of welding. In this study we assessed the effects of the use of wustite in partial replacement of Hematite, a mineral used in the coating of oxidizing electrodes. Five groups of electrodes were produced with a fixed percentage of the total weight of iron oxide and varying proportions of FeO and Fe2O3. Four pass welds in the flat position with 60° angle of inclination between the electrode plate and a 0.5m deep were performed. Weld metals were evaluated by chemical analysis, microscopy, diffusible hydrogen and micro-hardness. Digital image analysis methods were developed to measure inclusion area fraction from OM and SEM images, and the fraction of micro-constituents by OM. The results showed an increase of proeutectoid ferrite with increasing wustite content and a decrease with increasing carbon content, which, by its turn, decreased with increasing wustite content. Micro-hardness decreased with wustite content and increased with carbon content.
Itoh, Yoshito, Yasuo Kitane, and Xiao Chen. "Evaluation of repair design on corrosion-damaged steel pipe piles using welded patch plates under compression." 土木学会, 2011. http://hdl.handle.net/2237/18848.
Full textClark, Tad Dee. "An Analysis of Microstructure and Corrosion Resistance in Underwater Friction Stir Welded 304L Stainless Steel." Diss., BYU ScholarsArchive, 2005. http://contentdm.lib.byu.edu/ETD/image/etd872.pdf.
Full textItoh, Yoshito, Yasuo Kitane, Naohiko Watanabe, 義人 伊藤, 安雄 北根, and 尚彦 渡邉. "一般構造用鋼管へのあて板湿式水中溶接補修の継手挙動のモデル化." 土木学会, 2009. http://hdl.handle.net/2237/18843.
Full textMatsuoka, Kazumi, Naohiko Watanabe, Yoshito Itoh, Yasuo Kitane, 和巳 松岡, 尚彦 渡邊, 義人 伊藤, and 安雄 北根. "水中溶接鋼板添接補修された断面欠損鋼管の耐荷力実験." 土木学会, 2009. http://hdl.handle.net/2237/18844.
Full textJhan, J. M., and 詹智閔. "Simulation and Optimization of Underwater Plasma Arc Repair Welding of Irradiated Material." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/96811819474598823135.
Full text長庚大學
機械工程研究所
92
Metal components in nuclear power plants, after exposing in high dosage neutron radiation for a long time, will cause the material to produce helium. During repair welding of the irradiated components, the diffusion of is affected by heat and shrinkage stresses during cooling. The evolution and growth of helium bubbles may cause weld cracking. According to published research, underwater plasma arc welding (PAW) can produce residual compressive stresses, in the weld zone so it becomes the main subject of this study. Meanwhile, rapid cooling may significantly inhibit the diffusion of helium. Finite Element Method (FEM) is used to simulate the temperature and thermal stress fields during welding. To calculate the growth rate of helium bubbles in the weld heat affected-zone (HAZ) after repair welding, the results of simulation are incorporated in an equation, which evaluate thermal mechanical factors simultaneously. Utilizing this analysis results, one can choose proper welding parameters before repair welding of irradiated materials, which may experience different degrees of radiation exposure, to inhibit the diffusion of the helium effectively
Itoh, Y., N. Watanabe, and Y. Kitane. "EVALUATION OF STRENGTH RECOVERY OF REPAIRED STEEL PIPE PILES." 2008. http://hdl.handle.net/2237/18859.
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