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Caracteriza??o do cord?o na soldagem FCAW com um arame tubular "metal cored"
Starling, Cícero Murta Diniz;Modenesi, Paulo José;Borba, Tadeu Messias Donizete;
Soldagem & Inspe??o , 2011, DOI: 10.1590/S0104-92242011000300010
Abstract: this work evaluates the relationship between operational conditions and the characteristics of weld beads deposited with a 1.2 mm produced in brazil metal cored tubular wire (asme sfa-5.18: e70c-3m). welding trials were performed in downhand position on 12mm thick low-carbon steel plates using a constant voltage power supply. welding current and voltage, and wire feed rate were monitored in all trials. while the shielding gas composition (75%ar-25%co2 and 100%co2), wire polarity, and wire feed rate (7 and 9 m/min) were changed, other process variables, including electrode and arc lengths (16 mm and 3.5 mm, respectively) were kept constant throughout the experimental program. weld bead geometry parameters (penetration depth, reinforcement, width, fused and deposited areas, and weld dilution), presence of weld discontinuities, microstructure, and fusion zone hardness were measured and correlated to the operational conditions. operational conditions that yielded both high productivity levels (high deposition rates) and weld bead characteristics favored for the welding of thick plates of structural steels were determined.
Otimiza??o do processo de soldagem FCAW usando o erro quadrático médio multivariado
Paiva, Emerson José de;Rodrigues, Lucilene de Oliveira;Costa, Sebasti?o Carlos da;Paiva, Anderson Paulo de;Balestrassi, Pedro Paulo;
Soldagem & Inspe??o , 2010, DOI: 10.1590/S0104-92242010000100005
Abstract: the optimization of welding processes is not a trivial task, mainly due to the great number of exigible and desirable characteristics that must be analyzed. moreover, the optimization of a welding process with multiple characteristics without to consider the variance-covariance structure, may lead to inadequate optimum. to help in this task, a method of multiobjective optimization based in the multivariate mean square error applied in the study of multiple correlated characteristics of a fcaw (flux cored arc welding) welding process will be presented. this method characterized by a combined approach based in the response surface methodology, design of experiments and principal components analysis consisted in an attempt to achieve the nearest values to specific targets, for each studied characteristic (penetration, deposition rate, deposition efficiency, convexity index of the weld bead and dilution) considering the welding variables expressed in function of welding voltage (v), wire feed speed (va) and the contact tip to workpiece distance (d). the results point out a good adequacy of the proposed method.
Avalia o da soldagem multipasse de chapas espessas de a os inoxidáveis lean duplex UNS S32304 soldadas pelos processos SMAW, GMAW e FCAW: parte 1: propriedades mecanicas Evaluation of multipass welding of thick lean duplex stainless steel UNS S32304 plates welded by SMAW, GMAW and FCAW: part 1: Mechanical Properties
Ronaldo Cardoso Junior,Alexandre Queiroz Bracarense,Frederico Rodrigues Campos,Carla Soares Souza
Soldagem & Inspe??o , 2012, DOI: 10.1590/s0104-92242012000400005
Abstract: Os a os inoxidáveis duplex (AID) vêm se apresentando como uma excelente alternativa para aplica es em que alta resistência à corros o e alta resistência mecanica s o requeridas. Contudo, os AID, incluindo os a os inoxidáveis lean duplex, apresentam soldabilidade inferior em rela o aos a os inoxidáveis austeníticos. Nesse sentido, esse trabalho tem como objetivo a avalia o da soldagem multipasse de chapas 22 mm de espessura da liga inoxidável lean duplex UNS S32304, utilizando-se os processo SMAW, GMAW e FCAW e consumíveis com dois tipos de composi o química, 22%Cr9%Ni3%Mo e 23%Cr7%Ni, totalizando seis experimentos. Foram empregados chanfros em V com 60o e suporte ceramico para soldagem do passe de raiz, sendo que o aporte térmico foi mantido praticamente constante em 1,6 kJ.mm-1. Determinou-se os tempos de soldagem e a seqüência de passes, objetivando uma análise de produtividade, em seguida as juntas soldadas foram submetidas à END por raios x. Foram extraídos corpos de prova para ensaios de tra o, dobramento, Charpy a -30 oC e microdureza. A produtividade dos processos semi-automáticos se mostrou pelo menos 63 % maior que a do processo SMAW, enquanto o processo FCAW se mostrou de 6 a 18% mais rápido que o GMAW. Foram encontradas descontinuidades (porosidade) consideradas aceitáveis segundo ASME B31.3 em alguns dos experimentos, que n o influenciaram negativamente os resultados mecanicos, os quais se apresentaram acima requerimento do metal de base e especificado por normas de fabrica o. The duplex stainless steels (DSS's) have been placed as an excellent alternative for applications where high corrosion resistance and high mechanical strength are required. However, DSS's, including the lean duplex, present lower weldability than the austenitic stainless steels. Thus, this study aims to evaluate the multipass welding of 22 mm plates of lean duplex stainless steel alloy UNS S32304, using the process SMAW, GMAW and FCAW with consumables with two types of chemical composition, 22%Cr9%Ni3%Mo and 23%Cr7%Ni giving a total of six experiments. V-grooves with 60o and ceramic backing for welding the root pass were used and the heat input was maintained constant at 1.6 kJ.mm-1. It was determined the time and sequence of welding passes, aiming an analysis of productivity. The welded joints were subjected to x-ray END and specimens for tensile, bending, Charpy at -30oC and microhardness were extracted. The productivity of the semi-automatic processes proved to be at least 63% greater than the SMAW process while the process FCAW showed 6-18% faster than the GM
Desenvolvimento da ferrita delta na solda e ZTA resultante de soldagem plasma pulsada em um a o inoxidável supermartensítico Delta-ferrite development in weld and HAZ produced by pulsed plasma arc welding in a supermartensitic stainless steel
Sérgio L. Henke,Ramon S. C. Paredes,André R. Capra
Soldagem & Inspe??o , 2013,
Abstract: A ferrita delta é considerada uma fase indesejável na microestrutura dos a os inoxidáveis martensíticos haja vista a mesma poder influenciar no desempenho da resistência à fadiga, tenacidade e corros o sob-tens o. Sendo assim, o objetivo deste trabalho foi investigar o efeito da soldagem plasma pulsada sobre a distribui o e quantidade de ferrita delta em um a o inoxidável supermartensítico. Para tal foram obtidos cord es por meio de fus o superficial sobre uma amostra de a o inoxidável supermartensítico de alta liga utilizando corrente pulsada e convencional. Em seguida foi efetuada a caracteriza o microestrutural, em especial da ferrita delta, via análises metalográficas por meio de microscopia óptica e eletr nica de varredura . Os experimentos revelaram que, para o mesmo aporte térmico, a pulsa o de corrente promoveu a forma o de ferrita delta na forma de bandas ao longo do cord o de solda e redu o significativa desta fase na ZTA quando comparada à soldagem convencional. The objective of this study was to investigate the effect of pulsed plasma welding on the distribution and amount of delta ferrite which is considered an undesirable phase in a supermartensitic stainless steel. For such weld beads have been obtained by melting the surface of a sample of a high-alloy supermartensitic stainless steel using pulsed and conventional current. Microstructural characterization, especially of delta ferrite, was performed by metallographic analysis by means of optical microscopy and scanning electron microscopy. The experiments showed that for the same heat input, pulsed current promoted the formation of delta ferrite in the form of bands along the weld bead and caused a significant reduction of this phase in HAZ as compared to conventional welding.
Compara??o do desempenho operacional e das características do cord?o na soldagem com diferentes arames tubulares
Starling, Cícero Murta Diniz;Modenesi, Paulo José;Borba, Tadeu Messias Donizete;
Soldagem & Inspe??o , 2009, DOI: 10.1590/S0104-92242009000100003
Abstract: this paper compares the bead characteristics of welds deposited of carbon steel tubular wires. three tubular wires of 1.2 mm produced in brazil were used: rutilic (asme sfa-5.20: e71t-1/e71t-9/e71t-9m), basic (asme sfa-5.20: e71t-5/e71t-5m) and metal cored (asme sfa-5.18: e70c-3m). welding trials were performed in downhand position on thick (12 mm) low-carbon steel plates using a constant voltage power supply. welding current and voltage, and wire feed rate were monitored in all trials. for each tubular wire type, the shielding gas composition (75%ar-25%co2 and 100%co2) and wire feed rate (7 and 9 m/min) were changed, and other process variables, including electrode polarity (cc+), electrode and arc lengths (16 mm and 3.5 mm, respectively) were kept constant throughout the experimental program. weld bead geometry parameters (penetration depth, reinforcement, width, fused and deposited areas, and weld dilution), presence of weld discontinuities, fusion zone microstructure and hardness were measured and compared for the different tubular wires. operational conditions that yielded weld bead characteristics favored for the welding of thick plates of structural steels were determined.
Uma breve revis o histórica do desenvolvimento da soldagem dos a os API para tubula es A brief history review of development on API steels welding for pipeline
Jaime Casanova Soeiro Junior,David Bellentani Rocha,Sérgio Duarte Brandi
Soldagem & Inspe??o , 2013,
Abstract: Este trabalho enfoca o desenvolvimento dos a os API para tubula es desde o a o API 5L X42, desenvolvido em 1948, através de lamina o a quente seguida de tratamento térmico. Desde ent o foram feitos diferentes desenvolvimentos visando aumentar a resistência mecanica e a tenacidade, além de melhorar a soldabilidade. Entre eles, a adi o de elementos de liga, produzindo os a os ARBL e a utiliza o de rotas de processamento termomecanico durante a lamina o. Inicialmente a rota utilizada era a lamina o a quente controlada (TMCR), com utiliza o de elemento microligante como Nb para os a os X60 e o conjunto Nb e V para os a os X65 e X70, associado a uma redu o do teor de carbono. Posteriormente foi implantada a rota de fabrica o do a o por lamina o controlada seguida de resfriamento controlado (TMCP), com redu o de carbono e adi o de Nb e Ti para os a os X80, e adi es de Mo, Nb, Be Ti para os X100. A redu o do carbono foi motivada também para melhorar a sua soldabilidade e, por este motivo, estes a os s o soldados por diferentes processos de soldagem, como o eletrodo revestido. Desenvolvimentos recentes com raiz feita com MAG-TC e enchimento com arame tubular tem dado resultados animadores. This paper is a brief history on the development of pipelines steels since the API 5L X42 steel, developed in 1948 by hot rolling followed by heat treatment. Subsequently different developments were made to increase the strength and toughness of these materials, and to improve their weldability. Among them, the addition of microalloying elements, producing HSLA steels and thermomechanical processing routes during hot rolling. Initially the route used was the controlled hot rolling (TMCR), together with microalloying element such as Nb for X60 steel and Nb plus V for X65 and X70 steels, associated with a reduction in carbon content. Later, the thermomechanical controlled process (TMCP) manufacturing route was implemented together with carbon reduction and addition of Nb and Ti for X80 steels, and additions of Mo, Nb, B and Ti for X100. The reduction of carbon was also motivated to improve the weldability of theses steels and, for this reason; they are welded by various welding processes such as SMAW. Recent developments with GMAW with controlled short circuit transfer on the root and filling passes with FCAW has given encouraging results.
Evaluación de procedimientos de soldadura para revestimientos duros aplicados por el Proceso FCAW con transferencia metálica pulsada
BALDOMIR,LUIS A.; PLAZA R,ISIS E; IGNOTO,VICENTE;
Revista de la Facultad de Ingeniería Universidad Central de Venezuela , 2005,
Abstract: this work evaluates welding procedures for hardfacing done by pulsed fcaw using a theoretical approach developed by amin (1983) to predict the suitable combination of pulsed parameters which is based on burnoff, droplet detachment and arc stability criteria. definite hardfacing was carried out with the following welding parameters: ip= 300 a, ib = 50 a, tp= 3,1 ms, and tb= 10,7 ms. test specimens and their qualification were made according to asme code, section ix and aws b2.1-1998 standard. additionally, a macrographic evaluation was conducted. the destructive and non-destructive test results (visual and liquid penetrant inspection, hardness, chemical analysis and macrography) met the acceptance criteria. pulsed fcaw can be used for the hardfacing of low carbon steels, especially when high productivity and good quality is required, in spite of the tubular electrode complex metal transfer and the partial accomplishment of amin?s criteria.
Compara??o do desempenho operacional e das características do cord?o na soldagem com diferentes arames tubulares em polaridade negativa
Starling, Cícero Murta Diniz;Modenesi, Paulo José;Borba, Tadeu Messias Donizete;
Soldagem & Inspe??o , 2011, DOI: 10.1590/S0104-92242011000400006
Abstract: this paper compares the bead characteristics of welds deposited of carbon steel tubular wires. three tubular wires of 1.2mm produced in brazil were used: rutilic (asme sfa-5.20: e71t-1/e71t-9/e71t-9m), basic (asme sfa-5.20: e71t-5/e71t-5m) and metal cored (asme sfa-5.18: e70c-3m). welding trials were performed in downhand position on thick (12 mm) low-carbon steel plates using a constant voltage power supply in negative wire polarity (cc-). welding current and voltage, and wire feed rate were monitored in all trials. for each tubular wire type, the shielding gas composition (75%ar-25%co2 and 100%co2) and wire feed rate (7 and 9 m/min) were changed, and other process variables, including electrode and arc lengths (16 mm and 3.5 mm, respectively) were kept constant throughout the experimental program. weld bead geometry parameters (penetration depth, reinforcement, width, fused and deposited areas, and weld dilution), presence of weld discontinuities, fusion zone microstructure and hardness were measured and compared for the different tubular wires. operational conditions that yielded weld bead characteristics favored for the welding of thick plates of structural steels on negative wire polarity were determined.
Proposta de roteiro para a determina o das variáveis de soldagem do Processo TIG pulsado aplicado à soldagem de chapas finas Proposal of roadmap for determining the variables of pulsed TIG welding process applied to welding of thin plates  [cached]
Tiago Vieira da Cunha
Soldagem & Inspe??o , 2013,
Abstract: Na soldagem TIG pulsada a corrente varia entre dois níveis bem definidos de energia numa determinada frequência, sendo, portanto, necessário a regulagem de um conjunto de variáveis composto pela corrente de pulso, tempo de pulso, corrente de base, tempo de base, além da velocidade de soldagem. Entretanto, apesar de ser uma técnica t o amplamente difundida, na prática estas variáveis de soldagem muitas vezes s o reguladas de forma arbitrária. Isto pode conduzir ao uso ineficiente da pulsa o da corrente quando considerado o resultado final da solda, bem como nos aspectos de produtividade. Diante desta carência, este trabalho tem por objetivo apresentar um roteiro desenvolvido com o intuito de suprir a necessidade prática de se estabelecer critérios para auxiliar a determina o das variáveis da soldagem TIG pulsada, tomando como premissa a largura desejada para o cord o de solda final, a sobreposi o entre os pontos de solda que comp em o cord o e a velocidade de soldagem. Por fim, é apresentada uma aplica o deste roteiro na soldagem "bead on plate" de chapas de a o inox com 1,2 mm de espessura. In pulsed TIG welding the current varies between two well-defined energy levels in a given frequency being, therefore, necessary to the adjustment of a set of variables consisting of the peak current, peak time, background current, background time and the welding speed. However, despite being a technique so widespread, in practice these welding variables are often regulated arbitrarily. This can lead to inefficient use of the pulsed current regarding the end result of the weld as well as in the aspects of productivity. Given this shortage, this paper aims to present a roadmap developed in order to meet the practical need to establish criteria to assist in the determination of pulsed TIG welding variables, taking as its premise the desired width of the weld bead, overlap between the weld points comprising the weld bead and the welding speed. Finally, one application of this roadmap is presented in welding bead on plate of stainless steel plates with 1.2 mm thickness.
Optimization of welding parameters for weld penetration in FCAW  [PDF]
N.B. Mostafa,M.N. Khajavi
Journal of Achievements in Materials and Manufacturing Engineering , 2006,
Abstract: Purpose: This paper describes prediction of weld penetration as influenced by FCAW process parameters of welding current , arc voltage , nozzle-to-plate distance, electrode-to - work angle and welding speed . Optimization of these parameters to maximize weld penetration is also investigatedDesign/methodology/approach: It deals with the statistical technique of central composite rotatable design to develop a mathematical model for predicting weld penetration as a function of welding process parameters. The constrained optimization method is then applied to this model to optimize process parameters for maximizing weld penetrationFindings: The result obtained from the developed model indicates that the model predicts the weld penetration adequately. The optimization result also shows that weld penetration attains its maximum value when welding current, arc voltage , nozzle-to-plate distance and electrode-to-work angle are maximum and welding speed is minimumResearch limitations/implications: The statistical technique of developing a model for prediction of weld penetration is valid only within the specified limits of welding process parameters and hence maximization of penetration is also valid within these limits. This technique can be modified to include other parameters such as plate thickness affecting penetration.Practical implications: The statistical method for modeling and the optimization method used have found increasing applications in a variety of fields for investigation because through these methods research becomes economical , fast and versatile.Originality/value: The methods described in this paper for weld penetration prediction and optimization can eliminate the need for performing experiments on the basis of the conventional trial and error method which is time consuming and economically not justifiable.
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