Academic literature on the topic 'Multipass welding'
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Journal articles on the topic "Multipass welding"
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Saida, Kazuyoshi, Masashi Sakamoto, and Kazutoshi Nishimoto. "Mechanical Approach for Prediction of Microcracking in Multipass Weld Metal of Ni-Base Alloy 690." Materials Science Forum 580-582 (June 2008): 1–4. http://dx.doi.org/10.4028/www.scientific.net/msf.580-582.1.
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The occurrence of microcracks, especially ductility-dip crack in multipass weld metal during GTAW and laser overlay welding processes of Ni-base alloy 690 was predicted by the mechanical approach. The stress/strain analysis in multipass welds was conducted using the thermo elasto-plastic finite element method. The brittle temperature range for ductility-dip cracking (DTR) of the reheated weld metal was determined by the Varestraint test. Plastic strain in the weld metal accumulated with applying the weld thermal cycle in multipass welding. The plastic strain-temperature curve in the La free weld metal did not cross the DTR in the cooling stage of GTAW process, however, it crossed the DTR in the cooling stage of reheating process by subsequent welding. On the other hand, the plastic strain-temperature curves of any weld passes in the La added weld metal did not cross the DTR. Ductility-dip cracks occurred in the La free weld metal except for the final layer, however, any ductility-dip cracks did not occur in the La added weld metal during multipass welding. It could be understood that ductility-dip crack would occur during not only single-pass welding but also multipass welding when plastic strain intersected the DTR.
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Yushchenko, K. A., S. M. Kozulin, I. I. Lychko, and M. G. Kozulin. "Joining of thick metal by multipass electroslag welding." Paton Welding Journal 2014, no. 9 (September 28, 2014): 30–33. http://dx.doi.org/10.15407/tpwj2014.09.04.
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Galopin, M., Y. Laroche, J. L. Coté, and J. P. Boillot. "Optimising a multipass arc welding procedure." Welding International 5, no. 7 (January 1991): 537–43. http://dx.doi.org/10.1080/09507119109447833.
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Giętka, T., K. Ciechacki, and T. Kik. "Numerical Simulation of Duplex Steel Multipass Welding." Archives of Metallurgy and Materials 61, no. 4 (December 1, 2016): 1975–84. http://dx.doi.org/10.1515/amm-2016-0319.
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Abstract Analyses based on FEM calculations have significantly changed the possibilities of determining welding strains and stresses at early stages of product design and welding technology development. Such an approach to design enables obtaining significant savings in production preparation and post-weld deformation corrections and is also important for utility properties of welded joints obtained. As a result, it is possible to make changes to a simulated process before introducing them into real production as well as to test various variants of a given solution. Numerical simulations require the combination of problems of thermal, mechanical and metallurgical analysis. The study presented involved the SYSWELD software-based analysis of GMA welded multipass butt joints made of duplex steel sheets. The analysis of the distribution of stresses and displacements were carried out for typical welding procedure as during real welding tests.
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Ferreira, Dario, Antonio Alves, Rubelmar Cruz Neto, Thiago Martins, and Sérgio Brandi. "A New Approach to Simulate HSLA Steel Multipass Welding through Distributed Point Heat Sources Model." Metals 8, no. 11 (November 15, 2018): 951. http://dx.doi.org/10.3390/met8110951.
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Mechanical properties of welded joints depend on the way heat flows through the welding passes. In multipass welding the reheating of the heat affected zone (HAZ) can form local brittle zones that need to be delimited for evaluation. The difficulty lies in the choice of a model that can simulate multipass welding. This study evaluated Rosenthal’s Medium Thick Plate (MTP) and the Distributed heat Sources (DHS) of Mhyr and Gröng models. Two assumptions were considered for both models: constant and temperature-dependent physical properties. It was carried out on a multipass welding of an API 5L X80 tube, with 1016 mm (42″) external diameter, 16 mm thick and half V-groove bevel, in the 3G up position. The root pass was welded with Gas Metal Arc Welding (GMAW) process with controlled short-circuit transfer. The Flux Cored Arc Welding (FCAW) process was used in the filling and finishing passes, using filler metal E111T1-K3M-JH4. The evaluation criteria used were overlapping the simulated isotherms on the marks revealed in the macrographs and the comparison between the experimental thermal cycle and those simulated by the proposed models. The DHS model with the temperature-dependent properties presented the best results and simulated with accuracy the HAZ of root and second welding passes. In this way, it was possible to delimit the HAZ heated sub-regions.
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Saida, Kazuyoshi, Tomo Ogura, Shotaro Yamashita, and Yusuke Oikawa. "Computer Prediction of Phase Fraction in Multipass Weld of Duplex Stainless Steel - Proposal of Microstructural Improvement Welding Process -." Materials Science Forum 1016 (January 2021): 206–12. http://dx.doi.org/10.4028/www.scientific.net/msf.1016.206.
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Computer simulation of the α/γ phase transformation in multipass weld of duplex stainless steel was made for predicting the distribution of the γ phase fraction in the weld metal (WM) and HAZ. The kinetic equations including rate constants of the dissolution behaviour as well as precipitation behaviour of γ phase were determined by isothermal heat treatment test. Based on the kinetic equations determined, the distribution of the γ phase fraction in multipass weld of duplex stainless steel was calculated applying the incremental method combined with the heat conduction analysis in welding process. The γ phase fraction was reduced in the higher temperature HAZ and WM, however, that in the reheated HAZ and WM was increased and recovered to the base metal level. Microstructural analysis revealed that the calculated results of the γ phase fraction in multipass weld were consistent with experimental ones. Based on the computer prediction, the microstructural improvement welding (“reheat bead welding”) process, with analogous concept to the temper bead welding technique, was newly proposed for recovering the γ phase fraction in weld even in the as-welded situation.
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Redza, Mohd Ridhwan Mohammed, Yupiter H. P. Manurung, Robert Ngendang Ak. Lidam, Mohd Shahar Sulaiman, Mohammad Ridzwan Abdul Rahim, Sunhaji Kiyai Abas, Ghalib Tham, and Chan Yin Chau. "Distortion Analysis on Multipassed Butt Weld Using FEM and Experimental Study." Advanced Materials Research 311-313 (August 2011): 811–14. http://dx.doi.org/10.4028/www.scientific.net/amr.311-313.811.
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This paper investigates the simulation technique for analyzing the distortion behavior induced by welding process on welded plate which was clamped on one side. This clamping method is intended to enable the investigation of the maximum distortion on the other side. FEA software SYSWELD was employed to predict multipassed butt weld distortion of low carbon steel with thicknesses of 6 mm and 9 mm. The simulation begins with the development of model geometry and meshing type followed by suitable selection of heat source model represented by the Goldak’s double ellipsoid model. Other parameters such as travel speed, heat input, clamping method etc. were determined. The model is dedicated for multipass welding techniques using Gas Metal Arc Welding (GMAW). The experimental works were conducted by using Robotic welding process.
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Murugan, S., P. V. Kumar, B. Raj, and M. S. C. Bose. "Temperature distribution during multipass welding of plates." International Journal of Pressure Vessels and Piping 75, no. 12 (October 1998): 891–905. http://dx.doi.org/10.1016/s0308-0161(98)00094-5.
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Wu, J., J. Lucas, and J. S. Smith. "Weld bead placement system for multipass welding." IEE Proceedings - Science, Measurement and Technology 143, no. 2 (March 1, 1996): 85–90. http://dx.doi.org/10.1049/ip-smt:19960163.
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Sleptsov, O. I., I. T. Savvinov, and M. N. Sivtsev. "Angular strains in multipass stick electrode welding." Welding International 11, no. 12 (January 1997): 987–89. http://dx.doi.org/10.1080/09507119709447356.
Full textDissertations / Theses on the topic "Multipass welding"
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Smati, Z. "Development of a pulsed MIG system for fully automatic multipass welding." Thesis, Brunel University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355152.
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Nevasmaa, P. (Pekka). "Predictive model for the prevention of weld metal hydrogen cracking in high-strength multipass welds." Doctoral thesis, University of Oulu, 2003. http://urn.fi/urn:isbn:9514271815.
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This thesis studies controlling factors that govern transverse hydrogen cracking in high-strength multipass weld metal (WM). The experiments were concerned with heavy-restraint Y- and U-Groove multipass cracking tests of shielded-metal arc (SMAW) and submerged-arc (SAW) weld metals. Results of tensile tests, hardness surveys, weld residual stress measurements and microstructural investigations are discussed. The analytical phase comprised numerical calculations for analysing the interactions between crack-controlling factors. The objectives were: (i) the assessment of WM hydrogen cracking risk by defining the Crack-No Crack boundary conditions in terms of 'safe line' description giving the desired lower-bound estimates, and (ii) to derive predictive equations capable of giving reliable estimates of the required preheat/interpass temperature T0/Ti for the avoidance of cracking.
Hydrogen cracking occurred predominantly in high strength weld metals of Rp0.2 ≈ 580-900 MPa. At intermediate strengths of Rp0.2 ≈ 500-550 MPa, cracking took place in the cases where the holding time from welding to NDT inspection was prolonged to 7 days. Low strength WMs of Rp0.2 ≤ 480 MPa did not exhibit cracking under any conditions examined. Cracking occurrence was, above all, governed by WM tensile strength, weld diffusible hydrogen and weld residual stresses amounting to the yield strength. The appearance of cracking vanished when transferring from 40 to 6 mm thick welds. The implications of the holding time were more significant than anticipated previously. A period of 16 hrs in accordance with SFS-EN 1011 appeared much too short for thick multipass welds. Interpass time and heat input showed no measurable effect on cracking sensitivity, hence being of secondary importance. Equations were derived to assess the weld critical hydrogen content Hcr corresponding to the Crack-No Crack conditions as a function of either weld metal Pcm, yield strength Rp0.2 or weld metal maximum hardness HV5(max). For the calculation of safe T0/Ti estimates, a formula incorporating: (i) WM strength as a linear function of either weld carbon equivalent CET or weld HV5(max), (ii) weld build-up thickness aw in the form of tanh expression and (iii) weld diffusible hydrogen HD in terms of a combined [ln / power law] expression was found descriptive.
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Hanna, Farah. "A thermo-metallurgical-mechanical model for the numerical simulation of multipass GTA welding of martensitic X10CrMoVNb9-1 steel." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066416/document.
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En raison de sa stabilité microstructurale l'acier martensitique 'X10CrMoVNb9-1' est considéré comme un des candidats pour plusieurs futurs composants des réacteurs à hautes températures 'Very High Temperature Reactor' (VHTR). Ces épais composants (200 mm) sont assemblés par soudage TIG multi-passe. Ce procédé de soudage génère des cycles thermiques et thermomécaniques complexes au niveau de la Zone Affectée Thermiquement (ZAT). Cette thèse est la suite de celle de G.-M. Roux. Ce travail de six ans a pour but de prédire l'état microstructural après soudage dans la ZAT. G.-M. Roux a déjà développé une première version d'un modèle Thermo-Métallurgico-Mécanique (TMM) et a été validée en termes de contraintes résiduelles sur des essais de soudage simples mono-passe. Dans cette thèse une nouvelle version du modèle TMM est proposée, permettant d'améliorer les prévisions en termes de l'état microstructural post soudage dans la ZAT, et les contraintes résiduelles engendrées par l'opération de soudage.Cette thèse s¿appuie sur une approche de modélisation fine des transformations de phases, à savoir la modélisation de la transformation matériau de base - austénite lors d'un chargement anisotherme complexe, la modélisation de la transformation austénite - martensite et finalement la modélisation du revenu de la martensite. Sans oublier la caractérisation du comportement mécanique de chaque phase et l'étude du comportement multi-phasique. La simulation numérique avec le code éléments finis Cast3M de plusieurs procédés de soudage permet de comparer les modèles aux résultats expérimentauxDue to its microstructural stability, the martensitic steel 'X10CrMoVNb9-1 is considered a candidate for several future high temperatures reactor components. These thick components (200 mm) are assembled by GTA multi-pass welding. This welding process generates complex thermal and thermomechanical cycles in the Heat Affected Zone (HAZ). This thesis is following that of G.-M. Roux. This work of 6 years aims to predict the microstructural state after welding in the HAZ. A first version of a Thermo-Metallurgical-Mechanical model (TMM) has been developed and validated in terms of residual stresses on single-pass welding simple tests. In this thesis a new version of the TMM model is proposed to improve the forecasts in terms of the microstructural state and residual stresses post welding in the HAZ. The main improvements of this model TMM its capabilities to take into account the successive heating and cooling cycles, characterizing the multi-pass welding process. This thesis is based on a detailed modeling approach for phase transformations, namely modeling the transformation base material - austenite during anisothermal complex loadings, modeling transformation austenite - martensite and finally the martensite tempering modeling. Not to mention the characterization of the mechanical behavior of each phase and the study of multiphase behavior. Numerical simulation with the finite element code Cast3M of several welding processes was used to compare models with experimental results
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Santos, Julianne Ribeiro dos. "Influence of heat imput in multipass welding na corrosion resistence of UNS S32760 superduplex stainless steel welded pipe joints by GMAW process." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13611.
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CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel SuperiorO objetivo do presente trabalho à estudar o efeito da energia de soldagem sobre as transformaÃÃes microestruturais e a resistÃncia à corrosÃo na soldagem multipasse do aÃo inoxidÃvel superduplex UNS S32760 pelo processo MIG/MAG. A fim de atingir este objetivo, foram produzidas juntas soldadas variando-se a energia de soldagem nos seguintes nÃveis: 0,5 kJ/mm, 1,0 kJ/mm e 2,0 kJ/mm. Os valores de energia foram baseados em registros de qualificaÃÃo de procedimento de soldagem (RQPS) elaborados e aplicados nas unidades da PETROBRAS, exceto para a condiÃÃo de 2,0 kJ/mm, a qual foi extrapolada. As soldagens foram realizadas em juntas de tubos com 18 mm de espessura, com geometria em âJâ em uma bancada robotizada. Foi realizada uma caracterizaÃÃo microestrutural das regiÃes da Zona Fundida (ZF) e Zona Afetada pelo Calor (ZAC) pelas de Microscopia Ãtica (MO) e Microscopia EletrÃnica de Varredura (MEV). Como caracterÃsticas de resposta, avaliou-se o teor mÃdio de ferrita por anÃlise de imagens. A resistÃncia à corrosÃo foi avaliada pelas tÃcnicas eletroquÃmicas de polarizaÃÃo potenciodinÃmica com soluÃÃes de cloreto de sÃdio em diferentes concentraÃÃes (60g/L, 120g/L e 240g/L), polarizaÃÃo eletroquÃmica com reativaÃÃo potenciocinÃtica cÃclica (EPR-DL), teste eletroquÃmico de temperatura critica de pite seguindo a norma ASTM G150, ensaio de imersÃo em soluÃÃo de cloreto de ferro seguindo a norma ASTM G48 e ensaio de imersÃo em emulsÃes de petrÃleo preparadas com soluÃÃes de cloreto de sÃdio em diferentes concentraÃÃes (60g/L, 120g/L e 240g/L) e diferentes razÃes Ãgua/Ãleo (10%-90%, 30%-70% e 50%-50%). Os resultados indicaram que a energia de soldagem foi o fator que exerceu maior influÃncia sobre o teor mÃdio de ferrita na regiÃo da zona fundida da raiz das juntas. Houve precipitaÃÃes de nitretos de cromo em todas as energias e de fase sigma na energia de 1,0 kJ/mm e 2,0 kJ/mm. Os resultados do ensaio de EPR, assim como os ensaios de CPT mostraram que a zona fundida da energia de 1,0 kJ/mm se mostrou mais susceptÃvel a corrosÃo. Os ensaios de imersÃo seguindo a norma ASTM G48 mostraram que a temperatura onde ocorreu a formaÃÃo de pites com perda de massa considerÃvel quando as amostras entraram em contato com a soluÃÃo de cloreto de ferro foi em 50ÂC para todas as energias. E finalmente os ensaios de imersÃo em emulsÃes de petrÃleo, mostraram novamente que a energia de 1kJ/mm foi a que apresentou uma maior quantidades de pites.
The aim of this study was to evaluate the effect of heat imput in multipass welding on microstructural transformations and corrosion resistance of UNS S32760 superduplex stainless steel welded pipe joints by GMAW process. For this purpose, three levels of heat imput (0.5, 1.0 and 2.0 kJ/mm) were used. The heat imput values were based on records of welding procedure qualification (RWPQ) drawn up and applied in PETROBRAS units, except for the condition of 2.0 kJ/mm, which was an extrapolation. Weldings had been carried out for pipes with 18 mm thick, with joint geometry of J-groove. All welds were performed using a robotic workbench. The microstructural characterization of the weld regions like Fusion Zone (FZ) and Heat-Affected Zone (HAZ) were the performed by Ligth microscopy (LM) and scanning electron microscopy (SEM). The average ferrite content was determined by image analysis and was considerated as a characteristic response. The corrosion resistance was evaluated by electrochemical potentiodynamic polarization in sodium chloride solutions with different concentrations (60 g/L, 120 g/L and 240 g/L) aiming to simulate the concentration of chlorides in water production of oil reservoir of the pre-salt region. The to evaluate the electrochemical potentiokinetic reactivation cyclic of double loop (EPR-DL) corrosion was done to evaluate of susceptibility to corrosion. Electrochemical tests critical temperature for pitting according to ASTM G150, immersion tests in a solution of ferric chloride following the ASTM G48. Immersion tests in oil emulsions prepared with sodium chloride solutions at different concentrations (60 g/L 120 g/L and 240g/L), heated at 60ÂC and different ratio oil/water (10%-90%, 30%-70% and 50%-50%) were conduced. The results indicated that the welding heat imput was the factor that exerted the greatest influence on the average ferrite content in the fusion zone. There were precipitation of chromium nitrides at all heat imputs and sigma phase for the 1.0 kJ/mm and 2.0 kJ/mm. The EPR tests results as well as TCP tests showed that the fusion zone energy of 1.0 kJ/mm was more susceptible to corrosion. The immersion tests according to ASTM G48 showed that the temperature where the formation of pits occurred with considerable mass loss when the samples came in contact with the solution of ferric chloride was 50ÂC for all heat imputs. And finally, the immersion test in oil emulsions, showed again that the 1.0 kJ/mm test sample showed the greater amounts of pitting.
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Ferreira, Dario Magno Batista. "Metodologia para simulação computacional da distribuição de temperaturas para identificar sub-regiões reaquecidas da ZAC e avaliar suas influências nas propriedades mecânicas na soldagem multipasse de aço API 5L X80." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-08012018-110211/.
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Em projetos de oleodutos e gasodutos utilizam-se aços de alta resistência e baixa liga (ARBL), como o aço API 5L X80. Na soldagem multipasse destas tubulações, a zona afetada pelo calor (ZAC) do passe de raiz é submetida a um novo ciclo térmico pelos passes de soldagem subsequentes. Isto resulta em alterações nos valores das propriedades físicas. Nos aços ARBL, a ZAC de grãos grosseiros reaquecida intercriticamente (IC-ZACGG) pode se tornar uma zona frágil localizada, isto é, uma zona com maior dureza. Consequentemente, falhas estruturais podem ocorrer, ocasionando paradas não desejadas no transporte de fluidos. O objetivo deste trabalho é desenvolver uma metodologia baseada no modelo de fontes de calor distribuídas de Mhyr e Gröng, para avaliar o fluxo de calor na soldagem considerando as propriedades físicas dependentes da temperatura. Estender a aplicação desta ferramenta em soldagens multipasses para identificar sub-regiões da ZAC de um passe anterior sendo afetada pela ZAC de passes subsequentes. As isotermas simuladas foram validadas através de medições realizadas em macrografias de juntas soldadas. Os ciclos térmicos simulados foram validados através das temperaturas máximas atingidas e pelos tempos de resfriamento de 800 a 500 ºC (?t8-5) dos ciclos térmicos experimentais. Ao aplicar a metodologia proposta, foi possível delimitar com acurácia as regiões reaquecidas da ZAC e analisar os efeitos dos passes subsequentes em cada uma das sub-regiões da ZAC do passe de raiz. A IC-ZACGG na região do passe de raiz foi localizada, mas não se comportou como zona frágil devido à boa soldabilidade do aço API 5L X80 comprovada pelos ensaios de dureza e de tenacidade ao impacto Charpy-V.In pipelines projects, the high strength low alloy (HSLA) steels are used, such as the API 5L X80 steel. During the multipass welding of these pipes, the heat affected zone (HAZ) of the root pass is subjected to a new thermal cycle by the subsequent welding passes. This results in changes in the values of the physical properties. In the HSLA steels, the intercritical reheated coarse-grained heat-affected zone (IR-CGHAZ) can become a local brittle zone, that is, a region with greater hardness. Consequently, structural failures could happen, causing undesired shutdowns in fluid transportation. The objective of this work is to develop a methodology based on the distributed heat sources model of Mhyr and Gröng, to evaluate the heat flux in the welding considering the temperature-dependent physical properties. Extend the application of this tool in multipass welds to identify HAZ subregions of a previous pass being affected by the HAZ of subsequent passes. The simulated isotherms were validated through measurements made on macrographs of welded joints. The simulated thermal cycles were validated through the maximum temperatures reached and the cooling times from 800 °C to 500 ºC (?t8-5) of the experimental thermal cycles. By applying the proposed methodology, it was possible to accurately delimit reheated HAZ regions and analyze the effects of subsequent passes in each of the root pass HAZ subregions. The IRCGHAZ in the root pass region was localized, but it did not behave as a brittle zone due to the good weldability of the API 5L X80 steel as proven by the hardness and Charpy-V impact tests.
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Londoño, Antonio José Ramírez. "Precipitação de fases intermetálicas e austenita secundária na ZAC de soldagens multipasse de aços inoxidáveis duplex." Universidade de São Paulo, 2001. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-02012002-175418/.
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Os aços inoxidáveis duplex (AIDs) são materiais com um excelente desempenho tanto mecânico como à corrosão. Inúmeras pesquisas tem sido desenvolvidas para aprimorar a soldabilidade destas ligas. Algumas transformações de fase, que são passíveis de ocorrer durante o processo de soldagem, podem prejudicar seriamente o desempenho das juntas. Foram simuladas microestruturas da região da zona afetada pelo calor submetida a temperaturas elevadas (ZACTE), utilizando um modelo proposto de fluxo de calor. Abordaram-se aspectos fundamentais da precipitação de austenita secundária, de nitreto de cromo e as suas interações na ZACTE de soldas multipasse. Finalmente, foram realizados testes de tenacidade e de resistência à corrosão para avaliar o efeito das transformações de fase estudadas no desempenho das juntas soldadas. Os tratamento térmicos e simulações da ZACTE foram realizadas num equipamento GleebleÒ. As microestruturas foram analisadas mediante microscopia ótica e eletrônica de varredura e de transmissão. Junto com a microscopia eletrônica foram realizadas microanálises químicas das fases estudadas. Baseando-se nos resultados obtidos, verificou-se que nem todos os AIDs são susceptíveis de ferritizar. Este fato tem uma grande influência no comportamento metalúrgico e na soldabilidade destes aços. Quanto aos aspectos fundamentais da metalurgia destes aços, observou-se uma estreita interação entre a precipitação da austenita secundária e os nitretos de cromo, chegando-se a propor um mecanismo de nucleação da austenita secundária intragranular a partir dos nitretos. Por último, foi constatado que o efeito deletério da austenita secundária intragranular na resistência à corrosão pode ser evitado mediante a adequada elaboração do procedimento de soldagem.Duplex stainless steels (DSS) have excellent mechanical and corrosion properties. Many researches have been developed regarding the weldability of these alloys. There are some phase transformations that take place during the welding process, which may impair the welded joint behavior. High temperature heat-affected zone (HTHAZ) microstructures were simulated using a proposed heat flow model. Fundamental aspects of the secondary austenite and chromium nitride precipitation, and its interactions in the HTHAZ of multipass welds, were studied. In addition, toughness and corrosion tests were done to evaluate the influence of the studied phase transformations on the weld behavior. A GleebleÒ system was used to do the heat treatments and HTHAZ simulations. The microstructures were analyzed by means of optic and electron microscopy. Along with the electron microscopy it was done chemical microanalysis of the studied phases. Based on results, it was verified that not all DSSs can be ferritized. This fact has a strong influence on metallurgical behavior and weldability of these alloys. Regarding to the metallurgical fundamental aspects of these steels, it was observed a remarkable interaction between secondary austenite and chromium nitride precipitation. Thus, it was proposed a mechanism of intragranular secondary austenite precipitation from chromium nitrides. It was also verified, how the deleterious effect of intragranular secondary austenite in the corrosion resistance can be avoided by means of appropriate welding procedures.
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Ramard, Constant. "Étude expérimentale et numérique du soudage multipasse : application à un acier de construction navale." Thesis, Lorient, 2018. http://www.theses.fr/2018LORIS498/document.
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Les travaux effectués au cours de cette thèse ont pour objectif d’étudier et de modéliser une opération de soudage multipasse d’un acier à haute limite d’élasticité utilisé en construction navale. Dans ce cadre il s’agit de prédire les conséquences métallurgiques et mécaniques du procédé et tout particulièrement la répartition et l’intensité des contraintes résiduelles post- soudage nécessaires pour analyser l’intégrité de la structure navale en service. Deux maquettes représentatives d’un joint d’angle en Té ont permis de caractériser l’évolution des cycles thermiques, de la microstructure et des contraintes résiduelles (estimées par les méthodes du contour et du trou profond) après chaque passe de soudage. La suite de l’étude concerne la caractérisation et la modélisation du comportement thermo-métallurgique et thermo- mécanique des différentes phases apparaissant au cours du soudage. La dernière partie porte sur l’implémentation des modèles retenus dans le code de calcul élément finis Abaqus à l’aide de sous-programmes spécifiques. Une étape de transition d’échelle a permis de décrire le comportement thermomécanique multiphasé de cet acier. Des calculs préliminaires ont été conduits pour valider l’implémentation des modèles sur des cas simples. Différents couplages ont été réalisés, soit une analyse thermique puis thermo-métallurgique, pour estimer la dureté après chaque passe et enfin métallurgique-mécanique pour prédire les contraintes résiduelles pour le procédé de soudage multipasse. Les résultats des calculs éléments finis ont été discutés et comparés aux résultats expérimentaux obtenus dans la première partie de cette étudeThis thesis aims at studying and modeling a multipass welding operation of a high strength steel used in shipbuilding. In this framework, work focus on predicting the metallurgical and mechanical consequences of the process and, in particular, the residual stress distribution after welding. Since residual stresses can be detrimental to the performance of the welded product, their estimation is essential and numerical modelling is useful to predict them. Two welding mock-ups which are representative of a T- joint were used to characterize the evolution of thermal cycles, microstructure and residual stresses (measured by contour method and deep hole drilling) after each welding pass. Metallurgical and mechanical behaviors were thoroughly characterized in order to feed numerical models with reliable constitutive equations. The last part deals with the implementation of the models in the finite element calculation code Abaqus using specific subroutines. A scale transition procedure has been added to describe the thermomechanical multiphase behavior of the steel. Preliminary calculations were carried out for simple cases to validate the implementation of models. Different numerical couplings were made. First a thermal analysis then a thermo-metallurgical analysis, to estimate the hardness after each welding pass. Finally, a metallurgical-mechanical analysis is achieved for the prediction of residual stresses due to multipass welding. The results of the finite element calculations were discussed and compared with the experimental results obtained in the first part of this work
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Giraldo, Claudia Patricia Serna. "Precipitação de fases intermetálicas na Zona Afetada pelo Calor de Temperatura Baixa (ZACTB) na soldagem multipasse de aços inoxidáveis duplex." Universidade de São Paulo, 2001. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-03102001-103935/.
Full textAbstract:
Os aços inoxidáveis duplex são ligas Cr-Fe-Ni-Mo, que possuem uma microestrutura balanceada austenita-ferrita, e com excelentes propriedades mecânicas e de resistência à corrosão. Estas características os fazem muito utilizados nas industrias química, petroquímica, de papel, alimentícia e farmacêutica. O processamento destes aços geralmente envolve processos de soldagem, os quais devem ser elaborados cuidadosamente. Durante os ciclos térmicos experimentados na soldagem na zona afetada pelo calor, dependo do tempo de permanência no intervalo de temperaturas entre 650°C-950°C, podem ser precipitadas fases intermetálicas, como a fase sigma, que prejudicam as propriedades mecânicas e de resistência à corrosão. Três ligas comerciais de aços inoxidáveis duplex (AID) e superduplex (AISD) de denominação UNS S32304(AID), UNS S32750(AISD) e UNS S32760(AISD) foram submetidos a soldagem multipasse e a simulações de ciclos de soldagem na zona afetada pelo calor de temperatura baixa (ZACTB). As simulações foram realizadas em um dilatômetro e em um equipamento Gleeble®. Foram feitas comparações entre as microestruturas obtidas nas soldas reais e nos corpos-de-prova simulados. As microestruturas foram analisadas através de microscopia ótica e microscopia eletrônica de varredura. Foram também analisadas as fases precipitadas através de difração de Raios-X de resíduos extraídos, química e eletroliticamente, das amostras simuladas. Realizaram-se ensaios de corrosão intergranular e de polarização cíclica, para determinar o comportamento dos materiais à corrosão após a soldagem. Achou-se um bom acordo entre as microestruturas das soldas reais e as microestruturas simuladas. Encontrou-se que o aço UNS S32304 não precipitou nenhuma fase. No entanto, nos aços UNS S32750 e UNS S32760 foram encontradas fases precipitadas nos contornos de grão ferrítico. Essas fases foram identificadas como sigma e Cr2N. Entre estes dois últimos achou-se que o aço mais susceptível à precipitação de fases é o UNS S32760, provavelmente pela presença do W. Quanto ao comportamento à corrosão, não se observou nenhuma variação nos potenciais de pite após a simulação, enquanto que os potenciais de proteção sofreram uma queda comparando-se aos materiais na condição como-recebidos.Duplex stainless steels are Cr-Fe-Ni-Mo alloys. They possess balanced austenitic/ ferritic microstructure, excellent mechanical and corrosion resistance properties. Thus, these characteristics make them very used in chemical, petrochemical, cellulose, food and pharmaceutical industries. The processing of these steels generally involves welding processes, which should be carried out carefully. Depending on time from 650°C to 950°C temperature range during thermal cycles in heat affected zone, intermetallic phases can be precipitated, as sigma phase for instance. As a consequence, mechanical and corrosion resistance might be impaired. Three duplex (DSS) and superduplex (SDSS) stainless steel alloys, with denomination of UNS S32304 (DSS), UNS S32750 (SDSS), and UNS S32760 (SDSS), were submitted to real multipass welding and welding thermal cycles simulations of low temperature heat affected zone. The simulations were accomplished in a dilatometer and in a Gleeble® equipment. They were made comparisons among microstructures obtained in actual welds and simulated welding thermal cycles. Microstructures were analyzed by optical and electronic microscopy. X-ray diffraction analyses of extracted residues were studied. Tests of intergranular corrosion and cyclic potentiodynamic polarization were performed. Results indicated good agreement between actual welding and thermal cycles simulated microstructures. UNS S32304 steel did not precipitate any intermetallic phase. On the other hand, in UNS S32750 and UNS S32760 steels were found precipitated phases in the ferritic grain boundary. Those phases were identified as sigma and Cr2N. UNS S32760 were more susceptible phase precipitation, probably due to tungsten as an additional alloying element in this steel. Corrosion results indicated no observed variation in pitting potentials of simulated samples, meanwhile pitting protection potentials suffered a fall compared to materials in the as received condition.
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Londoño, Antonio José Ramirez. "Estudo da precipitação de nitreto de cromo e fase sigma por simulação térmica da zona afetada pelo calor na soldagem multipasse de aços inoxidáveis duplex." Universidade de São Paulo, 1997. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-27072001-165148/.
Full textAbstract:
Os aços inoxidáveis duplex são materiais com um excelente desempenho, devido às suas sobressalentes propriedades mecânicas e excelente resistência à corrosão. Uma composição química adequada e microestrutura balanceada são as responsáveis por esta combinação de propriedades. No entanto, são estes mesmos fatores que os fazem especialmente susceptíveis à precipitação de fases intermetálicas, com efeitos maléficos no seu desempenho. Durante os ciclos térmicos de uma soldagem multipasse, a precipitação de intermetálicos é crítica. Foi desenvolvido um método para simular os ciclos térmicos de uma solda multipasse. Usando este método, foi estudada a precipitação de nitreto de cromo e fase sigma na zona afetada pelo calor submetida a temperaturas abaixo de 950°C dos aços inoxidáveis duplex UNS S31803 e S32550. Foram estudadas energias de soldagem na faixa de 0,4 a 1,0 kJ/mm. Foi determinada mediante extração de precipitados, seguida de difração de raios X na câmara de Debye-Scherrer e microscopia eletrônica de transmissão, a precipitação de nitreto de cromo para energias de soldagem de 0,4 a 1,0 kJ/mm e de fase sigma para energias de soldagem de 0,6-1,0 KJ/mm, no UNS S32550. Já o UNS S31803 não apresentou precipitação alguma para as energias de soldagem estudadas. Baseando-se nos resultados verifica-se que durante uma soldagem multipasse o UNS S31803 é menos propenso que o UNS S32550 à precipitação de intermetálicos na zona afetada pelo calor submetida a temperaturas abaixo de 950°C.Duplex stainless steels belong to a group of high performance stainless steels regarding to corrosion and mechanical properties. These achievements are related to a suitable chemical composition and a balanced microstructure. During welding thermal cycles the microstructure changes and, consequently, corrosion and mechanical properties might be impaired due to a precipitation of intermetallic phases. This precipitation is an issue to be addressed for multipass welding. It was developed a method for simulate the multipass welding thermal cycles. Using this method chromium nitride and sigma phase precipitation was studied in a simulated heat affected zone of multipass welding (three passes) of UNS S31803 and UNS S32550 duplex stainless steels with different heat inputs (0,4 to 1,0 kJ/mm). The HAZ simulated region was below 950°C maximum temperature. Microstructural characterization of simulated samples showed discontinuous films of a precipitated phase at ferrite/ferrite grain boundaries and ferrite/austenite interfaces were observed only in a UNS S32550 duplex grade for all heat inputs simulated. This suggests that sigma phase and chromium nitride precipitation took place during sample thermocycling. X-ray diffraction in a Debye-Scherrer chamber of extracted precipitates and electron diffraction by TEM confirmed the presence of chromium nitrides for all range of heat input studied and sigma phase for heat input above 0,6 kJ/mm. On the other hand, microstructural analysis of UNS S31803 simulated samples did not present precipitation of intermetallic phases in the tested temperature range of HAZ. Based on these results, UNS S31803 is more resistant than UNS S32550 to intermetallic phases precipitation in multipass welding.
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Oliveira, Francisco Josà dos Santos. "AlÃvio de tensÃes residuais em junta soldada com arame de baixa temperatura de transformaÃÃo martensÃtica." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=16038.
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FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgicoCoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior
A soldagem multipasse de chapas grossas impÃe à junta soldada um estado de tensÃes residuais que pode ser muito prejudicial quando estas estÃo em serviÃo. Existem vÃrios fenÃmenos capazes de alterar os nÃveis de tensÃes residuais de soldagem nos materiais, um deles à a transformaÃÃo de fases. Este trabalho apresenta um estudo comparativo dos nÃveis de tensÃes residuais em trÃs juntas soldadas, produzidas com metais de adiÃÃo diferentes pelo processo arame tubular. Um arame eletrodo de aÃo inoxidÃvel martensÃtico Fe-12%Cr-5%Ni com baixa temperatura de transformaÃÃo foi o primeiro a ser utilizado, o segundo, um aÃo inoxidÃvel austenÃtico Fe-18,5%Cr-10%Ni, e finalmente, um aÃo baixa liga Fe-1,25%Cr-0,5%Mo. No processo de soldagem foi utilizada uma bancada robotizada com fonte multiprocesso para confecÃÃo das juntas, sendo o aÃo ABNT 4140 o metal de base. As tensÃes residuais foram medidas na superfÃcie das juntas soldadas atravÃs do mÃtodo de difraÃÃo de raios-X. TambÃm foram avaliadas as seguintes propriedades mecÃnicas; resistÃncia à traÃÃo, tenacidade e microdureza, bem como, as microestruturas resultantes na zona fundida, zona afetada pelo calor e metal de base. Os resultados mostraram que a junta produzida com arame eletrodo que sofreu transformaÃÃo martensÃtica a baixa temperatura apresentou nÃveis considerÃveis de tensÃo residual compressiva, ao contrÃrio das demais juntas que apresentaram tensÃo residual trativa na maioria dos pontos medidos. Nos ensaios de traÃÃo, a junta de baixa temperatura de transformaÃÃo martensÃtica apresentou elevados limites de escoamento e de resistÃncia à traÃÃo, e a sua ruptura ocorreu na interface entre o metal de base e o metal de solda. Nos ensaios de impacto da mesma junta, os valores de energia absorvida no metal de solda e zona termicamente afetada se apresentaram relativamente baixos.
The multi-pass welding of thick plates imposes to the welded joint a state of residual stresses that can be very harmful when they are in service. There are various phenomena that can alter the levels of residual stresses after materials welding; one of them is phase transformation. This work presents a comparative study of the levels of residual stresses in three welded joints, produced with different filler metals by Flux Cored Arc Welding (FCAW). A martensitic stainless steel wire Fe-12% Cr-5% Ni with low transformation temperature was the first to be used. After this an austenitic stainless steel Fe-18.5% Cr-10% Ni was used and finally a low alloy steel Fe -1.25% Cr-0.5% Mo. In the welding process, we used a workbench robot with multiprocess source for making joints, and the AISI 4140 the base metal.. Residual stresses were measured on the surface of welded joints using X-ray diffraction method. Tensile strength, toughness and hardness, as well as the resultant microstructure in weld metal, heat affected zone and base metal were evaluated. The results showed that the joint produced with wire electrode that has undergone low temperature martensitic transformation presents significant levels of compressive residual stress, unlike the other joints which present tensile residual stress at most of the measured points. In tensile tests, the joint of martensitic stainless steel showed high yield limits and tensile strength, and its rupture occurred at the interface between base metal and weld metal. Results of the impact tests of this joint showed relatively low absorbed energy values at the weld metal and heat affected zone.
Books on the topic "Multipass welding"
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Smati, Z. Development of a pulsed MIG system for fully automatic multipass welding. Uxbridge: Brunel University, 1985.
Find full textBook chapters on the topic "Multipass welding"
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Lim, Yong Chae, Samuel Sanderson, Murray Mahoney, Dongxiao Qiao, Yanli Wang, Wei Zhang, and Zhili Feng. "Mechanical Properties and Microstructural Characterization of a Multilayered Multipass Friction Stir Weld in Steel." In Friction Stir Welding and Processing VII, 81–90. Cham: Springer International Publishing, 2013. http://dx.doi.org/10.1007/978-3-319-48108-1_9.
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Lim, Yong Chae, Samuel Sanderson, Murray Mahoney, Dongxiao Qiao, Yanli Wang, Wei Zhang, and Zhili Feng. "Mechanical Properties and Microstructural Characterization of a Multilayered Multipass Friction Stir Weld in Steel." In Friction Stir Welding and Processing VII, 81–90. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2013. http://dx.doi.org/10.1002/9781118658345.ch9.
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Vemanaboina, Harinadh, R. Gopi Chandh, P. Sivakrishna, A. Kishore Kumar, K. Malli Karjuna, and Y. Sailinga Reddy. "A X-Ray Diffraction Study of Residual Stresses Due to Multipass Welding of INCONEL600." In Advances in Lightweight Materials and Structures, 561–67. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-7827-4_57.
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Lauridsen, J. K., O. Madsen, and H. Holm. "An Architecture for Robot Off-line Programming of Filling Welds for Multipass GMA-Welding of Pipe Branches." In Computer Applications in Production Engineering, 866–75. Boston, MA: Springer US, 1995. http://dx.doi.org/10.1007/978-0-387-34879-7_90.
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Esnaola, Jon Ander, Ibai Ulacia, Arkaitz Lopez-Jauregi, and Done Ugarte. "Residual Stress Pattern Prediction in Spray Transfer Multipass Welding by Means of Numerical Simulation." In Residual Stress Analysis on Welded Joints by Means of Numerical Simulation and Experiments. InTech, 2018. http://dx.doi.org/10.5772/intechopen.72134.
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"3D numerical model of austenitic stainless steel 316L multipass butt welding and comparison with experimental results." In Analysis and Design of Marine Structures, 395–402. CRC Press, 2009. http://dx.doi.org/10.1201/9780203874981-51.
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Papazoglou, V., and A. Kyriakongonas. "3D numerical model of austenitic stainless steel 316L multipass butt welding and comparison with experimental results." In Analysis and Design of Marine Structures, 371–76. CRC Press, 2009. http://dx.doi.org/10.1201/9780203874981.ch42.
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Field, David P., and Mukul Kumar. "Electron Backscatter Diffraction." In Encyclopedia of Aluminum and Its Alloys. Boca Raton: CRC Press, 2019. http://dx.doi.org/10.1201/9781351045636-140000410.
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Electron backscatter diffraction (EBSD) is a scanning electron microscope (SEM) based technique that is used to obtain local information on the crystallographic character of bulk crystalline and polycrystalline materials. Topics discussed in this article include: EBSD system overview, multiphase analysis, and application to aluminum integrated circuit interconnects, dislocation structure analysis, analysis of grain boundary networks, and application to friction stir welding of aluminum alloys.
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Sciaky, M., R. Cazes, and G. Sayegh. "Evolution et Tendance de l'Automatisation dans les Lignes d'Assemblage par Resistance a Points Multiples." In Automation and Robotisation in Welding and Allied Processes, 383–84. Elsevier, 1985. http://dx.doi.org/10.1016/b978-0-08-032533-0.50047-5.
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S. Wei, P., and S. C. Kuo. "Annular Flow Effects on Pore Formation in High-Intensity Beam Welding or Drilling." In Advances in Multiphase Flow and Heat Transfer (Volume 1), 213–32. BENTHAM SCIENCE PUBLISHERS, 2012. http://dx.doi.org/10.2174/978160805080210901010213.
Full textConference papers on the topic "Multipass welding"
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Novotný, Ladislav, Hamilton Ferreira Gomes de Abreu, Miloslav Béreš, and Jozef Zajac. "Finite element analysis of multipass welding using LTT filler material." In Third International Conference on Material Science, Smart Structures and Applications: (ICMSS 2020). AIP Publishing, 2021. http://dx.doi.org/10.1063/5.0039489.
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Jiang, Wei, and Kadda Yahiaoui. "Finite Element Prediction of Residual Stress Distributions in a Multipass Welded Piping Branch Junction." In ASME 2006 Pressure Vessels and Piping/ICPVT-11 Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/pvp2006-icpvt-11-94033.
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Piping branch junctions and nozzle attachments to main pressure vessels are common engineering components used in the power, oil and gas, and shipbuilding industries amongst others. These components are usually fabricated by multipass welding. The latter process is known to induce residual stresses at the fabrication stage which can have severe adverse effects on the in-service behavior of such critical components. It is thus desirable if the distributions of residual stresses can be predicted well in advance of welding execution. This paper presents a comprehensive study of three dimensional residual stress distributions in a stainless steel tee branch junction during a multipass welding process. A full 3D thermo-mechanical finite element model has been developed for this purpose. A newly developed meshing technique has been used to model the complex intersection areas of the welded junction with all hexahedral elements. Element removal/reactivate technique has been employed to simulate the deposition of filler material. Material, geometry and boundary nonlinearities associated with welding were all taken into account. The analysis results are presented in the form of stress distributions circumferentially along the weldline on both run and branch pipes as well as at the run and branch cross sections. In general, this computational model is capable of predicting 3D through thickness welding residual stress, which can be valuable for structural integrity assessments of complex welded geometries.
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Gontcharov, Alexandre, Joe Liburdi, Paul Lowden, Douglas Nagy, and Nikesh Patel. "Self Healing Fusion Welding Technology." In ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-26412.
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The properties of laser, microplasma and GTAW welds on representative gas turbine blade materials are disclosed. Proprietary filler materials and technology were used to clad multipass welds onto IN738, RenéN5 and CMSX4 alloys which were then subject to vacuum heat treatment before testing. It was found that welds with a bulk content of boron up to 0.6 wt. % demonstrated a capability to heal cracks adjacent to the fusion line (HAZ cracks) and they exhibited superior tensile and stress-rupture properties at a temperature of 982°C. Welds that comprised 1.5 to 2% silicon had superior oxidation resistance at a temperature of 995°C. Combined alloying of welds with moderate amount of boron and silicon produced a unique combination of both high mechanical and oxidation properties. Healing of HAZ cracks took place during post weld heat treatment at a temperature exceeding the solidus temperature of the weld metal eutectics but below of a solidus temperature of the base material. It was found that boron and silicon additives reduced welding pool solidification temperature and increased the solidus–liquidus range. At this temperature a partial re-melt of eutectics occurred allowing healing of HAZ and weld solidification cracks while weld geometry was supported by a continuous framework of high temperature dendrites. This allows the tip repair of turbine blades manufactured of precipitation strengthened superalloys that are normally prone to weld cracking.
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Jiang, Wei, Kadda Yahiaoui, Chang J. Wang, Frank R. Hall, and Tahar Laoui. "FE Predictions of Temperature Distributions in a Multipass Welded Piping Branch Junction." In ASME/JSME 2004 Pressure Vessels and Piping Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/pvp2004-2283.
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This contribution deals with the complex temperature profiles that are generated by the welding process in the intersection region of thick walled, cylinder-cylinder junctions. These affect material microstructure, mechanical properties and residual stresses. Knowledge of the thermal history and temperature distributions are thus critical in developing control schemes for acceptable residual stress distributions to improve in-service component behavior. A comprehensive study of 3D temperature distributions in a stainless steel tee branch junction during a multipass welding process is presented. A newly developed partitioning technique has been used to mesh the complex intersection areas of the welded junction. Various phenomena associated with welding, such as temperature dependent material properties, heat loss by convection and latent heat have been taken into consideration. The temperature distribution at various times after deposition of certain passes and the thermal cycles at various locations are reported. The results obtained in this study will be used for on-going and future analysis of residual stress distributions. The meshing technique and modeling method can also be applied to other curved, multipass welds in complex structures.
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Dewees, David J. "Comparison of 2D and 3D Welding Simulations of a Simple Plate." In ASME 2012 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/pvp2012-78573.
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Computer analysis of the welding process can now be reasonably carried out in 3D for many simple geometries. This allows direct comparison with more conventional 2D approximations for common heavier-walled joints. Multipass plate butt weld examples are presented, using a range of analysis techniques based on commercial finite element software and the results compared to one another. This project has application to a larger effort to understand the relationship between far-field displacement control boundary conditions and weld residual stress fields. Heat source, high temperature material property, constitutive and element birth and death modeling are also addressed.
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Valiorgue, Frédéric, Alexandre Brosse, Vincent Robin, Philippe Gilles, Joel Rech, and Jean Michel Bergheau. "Chained Welding and Finish Turning Simulations of Austenitic Stainless Steel Components." In ASME 2013 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/pvp2013-97980.
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The chaining of manufacturing processes is a major issue for industrials who want to understand and control the quality of their products in order to ensure their in-service integrity (surface integrity, residual stresses, microstructure, metallurgical changes, distortions,…). Historically, welding and machining are among the most studied processes and dedicated approaches of simulation have been developed to provide reliable and relevant results in a industrial context with safety requirements. As the simulation of these two processes seems to be at an operational level, the virtual chaining of both must now be applied with a lifetime prediction prospect. This paper will first present a robust method to simulate multipass welding processes that has been validated through an international round robin. Then the dedicated “hybrid method”, specifically set up to simulate finish turning, will be subsequently applied to the welding simulation so as to reproduce the final state of the pipe manufacturing and its interaction with previous operations. Final residual stress fields will be presented and compared to intermediary results obtained after welding. The influence of each step on the final results will be highlighted regarding surface integrity and finally ongoing validation works and numerical modeling enhancements will be discussed.
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Lhachemi, Dounia, Vincent Robin, Philippe Gilles, Philippe Mourge, and Mehdi Zemmouri. "3D Simulation of a Peripheral Adapter J-Groove Attachment Weld in a Vessel Head." In ASME 2010 Pressure Vessels and Piping Division/K-PVP Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/pvp2010-25703.
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In Pressurized Water Reactors, most of components have large thicknesses and their manufacturing processes often require multipass welding. In spite of the stiffness of these components, the distortion issue may be important for operational requirements (e.g. misalignment) or controllability reasons (Non Destructive Examinations have to be feasible). These requirements may be difficult to meet by adjusting welding processes. Indeed because of the complexity of mechanisms involved during a welding operation and the high number of influencing parameters, this process is still essentially based on the experience of the welder. Furthermore the experimental estimation of the stress and distortion level in the component remains a difficult task that is subject to errors even if techniques are currently improved to become more accurate. That is the reason why AREVA NP has put many efforts into developing welding numerical simulations, in order to have a better understanding of the involved physical phenomena and also to predict the residual state allowing a qualification of the manufacturing processes in the very early phase of the welded components design. Within the framework of a R&D program whose main objective was to improve tools for numerical simulation of industrial cases of welding, AREVA NP has decided to validate new methodologies based on 3D computation by comparison with measurements. For this validation task the chosen test case concerns a peripheral adapter J-groove attachment weld on a vessel head. For such an application, operations of post-joining straightening have to be limited, if not prohibited, because of their cost or the impossibility to use them in front of a steel giant. The control of distortions during welding operations constitutes an important stake for which simulation can be of great help. Regarding distortions issues, an accurate metal deposit sequence modeling is mandatory, especially for multipass welding on such a complex geometry. The aim of this paper is to present, through a peripheral adapter J-groove attachment weld mock-up, the capabilities AREVA NP has in order to predict, in an efficient way the consequences of complex welding operations requiring 3D transient numerical simulations.
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Courtin, Stéphan, Xavier Ficquet, Thi Thuy Trang Lê, Philippe Gilles, and Miguel Yescas. "Residual Stress Predictions on a 29″ Narrow Gap Dissimilar Metal Weld and Comparison With a 14″ Configuration." In ASME 2012 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/pvp2012-78089.
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AREVA has developed narrow gap weld techniques to perform junctions between low alloy steel heavy section components and austenitic stainless steel piping systems. In parallel, for a good understanding of welding and post weld heat treatment consequences, numerical welding simulation has already demonstrated its relevance to predict residual stress fields in welded components [1]. This paper presents Finite Element (FE) simulations of a 29″ multipass narrow gap Dissimilar Metal Weld (DMW) configuration, the welding simulation including non linear kinematic hardening models, phase transformations and visco-plastic calculations for reproducing the post weld heat treatment. The numerical results are compared to measurements obtained by the deep hole drilling technique [2]. This work gives another evidence of the relevance of the numerical welding simulation. Particularly, the comparison with a 14″ configuration [3] gives some elements to assess on the validity of both numerical and experimental techniques and on the weld thickness effect.
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Huang, Hui, Jian Chen, Blair Carlson, Hui-Ping Wang, Paul Crooker, Gregory Frederick, and Zhili Feng. "Prediction of Residual Stresses in a Multipass Pipe Weld by a Novel 3D Finite Element Approach." In ASME 2018 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/pvp2018-85044.
Full textAbstract:
Due to enormous computation cost, current residual stress simulation of multipass girth welds are mostly performed using two-dimensional (2D) axisymmetric models. The 2D model can only provide limited estimation on the residual stresses by assuming its axisymmetric distribution. In this study, a highly efficient thermal-mechanical finite element code for three dimensional (3D) model has been developed based on high performance Graphics Processing Unit (GPU) computers. Our code is further accelerated by considering the unique physics associated with welding processes that are characterized by steep temperature gradient and a moving arc heat source. It is capable of modeling large-scale welding problems that cannot be easily handled by the existing commercial simulation tools. To demonstrate the accuracy and efficiency, our code was compared with a commercial software by simulating a 3D multi-pass girth weld model with over 1 million elements. Our code achieved comparable solution accuracy with respect to the commercial one but with over 100 times saving on computational cost. Moreover, the three-dimensional analysis demonstrated more realistic stress distribution that is not axisymmetric in hoop direction.
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Duch, J., and J. DuPont. "Effect of Multipass Welding on the Microstructural Evolution and Mechanical Properties of High Strength Low Alloy 100 Steel." In MS&T18. MS&T18, 2018. http://dx.doi.org/10.7449/2018mst/2018/mst_2018_830_840.
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