Pulsed current gas metal arc welding of P91 steels using metal cored wires

Krishnan, S.; Kulkarni, D. V.; De, A.

doi:10.1016/j.jmatprotec.2015.11.007

Cited by 16 publications

(9 citation statements)

References 19 publications

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“…However, NbCN was only found in the PM and HAZ. In addition, trying to overcome the lack of productivity characteristic of the conventional TIG process, Krishnan et al [6] used the pulsed gas arc welding (GMAW-P) process using a cored wire filler material to weld 12 mm thick P91 steel sheets in a single pass. The authors reported that the best welding results were obtained using 75 • bevel aperture and 1.38 kJ/mm heat input, which corresponds to a welding speed of 320 mm/min and a current intensity of 270 A.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Welded Joints in P91 Steel under Different Heat-Treatment Conditions

Silva

Pinho

Péreira

et al. 2020

Metals

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P91 steel has been of interest to many researchers over the past two decades. This interest is because this steel has very interesting characteristics for application in power plants, where it is common to have pipes that need to support steam at temperatures between 570 and 600 °C, and at pressures in the range of 170 to 230 bar. These working conditions are quite severe for most common steels, requiring increased high-temperature mechanical strength as well as high creep resistance. The manufacture of these pipes normally includes welding operations, which must preserve the main characteristics of this type of steel. This justifies the concern of the researchers to ensure the best welding conditions so that the preservation of the properties of these steels becomes possible. The present work intends to depict the best results obtained varying the heat-treatment conditions applied to weldments made on heat-resistant steel P91. This steel usually takes the designation SA 213 T91 (seamless tube) or SA 335 P91 (seamless pipe), according to ASME II, as well as the designation X10CrMOVNb9-1 according to EN 10216-2. The purpose of this study is to compare the behavior of pipe welding under different post-welding heat-treatment (PWHT) conditions. One of them is performed with thermal cycles (preheating, post-heating, and the post-weld heat treatment) in agreement with most construction codes and standard rules. The second one is performed without any thermal cycle before and after welding. Both welds were made by the same process, TIG (Tungsten Inert Gas, or GTAW—Gas Tungsten Arc Welding) in the horizontal position (2G according to ASME IX) and the same welding parameters. In order to evaluate the results obtained in the welds, microstructure analyses, hardness measurements, bending tests, and tensile tests at room and high temperature (600 °C) have been performed. Other tests were also carried out according to the quality procedures, such as visual, penetrant dye, and X-ray tests. Regarding the different strategies used in the heat treatments, the best results have been obtained using a strategy similar to the one currently in use and recommended by construction codes and steel manufacturers but excluding the phases’ transformation time, and it was possible to observe that the tensile strength is impaired by about 2% to 9% at room and elevated temperatures, respectively; the elongation is reduced by 39% at room temperature but keeps a good performance at elevated temperature; the hardness profile is very similar at both temperatures; the microstructure presented is compatible with the requirements; and no cracking trend has been reported. Thus, a new strategy for the welding heat treatment of grade 91 steels was drawn, saving energy and processing time.

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Section: Introductionmentioning

confidence: 99%

Evaluation of Welded Joints in P91 Steel under Different Heat-Treatment Conditions

Silva

Pinho

Péreira

et al. 2020

Metals

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“…Another important factor in GMAW is wire feed rate that controls the deposition rate. In constant-voltage recti er-type GMA machines, the wire feed speed with arc voltage setting controls the amperage (an increase in wire feed speed and arc voltage increases the amperage while welding and vice versa) [1]. Therefore, on GAAM-PARS MIG-SP 501W machine, the welding current is not an independent factor and welding amperage is a function of the feed rate and voltage.…”

Section: Design Of Experiments and Experimental Resultsmentioning

confidence: 99%

“…Nozzle-to-plate distance (D), arc voltage (V ), wire feed rate (F ), and welding speed (S) are the most prominent parameters in GMAW process [1,3,5]. Similarly, process quality measures include Bead Penetration (BP), Bead Width (BW), Bead Height (BH), and Heat-A ected Zone (HAZ).…”

Section: Design Of Experiments and Experimental Resultsmentioning

confidence: 99%

“…Because of its consumable electrode, GMAW has a higher productivity than another generally used arc welding process, i.e. Gas Tungsten Arc Welding (GTAW) [1]. High productivity rate due to the continuous feed of wire electrode, low weld discontinuity, no slag inclusion, and low thermal hazard on base metal is the main merit of this process [2].…”

Section: Introductionmentioning

confidence: 99%

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Simultaneous Optimization of Joint Edge Geometry and Process Parameters in Gas Metal Arc Welding Using Integrated ANN - PSO Approach

2017

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Abstract. Gas Metal Arc Welding (GMAW) is one of the most extensively used processes in automated welding due to its high productivity. However, to simultaneously achieve several con icting objectives such as reducing production time, increasing product quality, full penetration, proper joint edge geometry, and optimal selection of process parameters, a multi-criteria optimization procedure must be used. The aim of this research is to develop a multi-criteria modeling and optimization procedure for GMAW process. To simultaneously predict Weld Bead Geometry (WBG) characteristics and Heat-A ected Zone (HAZ), a Back Propagation Neural Network (BPNN) has been proposed. The experimentally derived data sets are used in training and testing of the network. Results demonstrate that the nely tuned BPNN model can closely simulate actual GMAW process with less than 1% error. Next, to simultaneously optimize process characteristics, the BPNN model is inserted into a Particle Swarm Optimization (PSO) algorithm. The proposed technique determines a set of values for parameters and the workpiece groove angle in such a way that a pre-speci ed WBG is achieved while the HAZ of the weld joint is minimized. Optimal results are veri ed through additional experiments.

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“…Além de não existir a mesma quantidade de trabalhos disponíveis, na grande maioria dos casos estes abordam a pulsação da corrente no processo FCAW com base na comparação com o GMAW ou com o processo FCAW convencional. Neste contexto, têm-se o trabalho de Krishnan et al [6] que realizaram um estudo quanto ao emprego da corrente pulsada em arames tubulares. De um modo geral, o estudo mostrou que a soldagem FCAW com corrente pulsada é capaz de aumentar a taxa de deposição em 42% e velocidade de soldagem em 20%, além de conferir melhores propriedades mecânicas nos cordões de solda resultantes, quando comparado com a soldagem com arames maciços.…”

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Uma Contribuição na Determinação das Variáveis da Corrente Contínua Pulsada para o Arame Tubular E71T-1M

2018

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Este é um artigo publicado em acesso aberto (Open Access) sob a licença Creative Commons Attribution Non-Commercial, que permite uso, distribuição e reprodução em qualquer meio, sem restrições desde que sem fins comerciais e que o trabalho original seja corretamente citado.Resumo: Este trabalho tem por objetivo principal implementar o processo de soldagem FCAW com corrente contínua pulsada. Para tanto, foi analisada a influência da Distância de Bico de Contato-Peça (DBCP) em dois níveis (19 e 24 mm) e o tamanho do diâmetro da gota (Dg) de acordo com o seguinte critério: Diâmetro da gota igual ao diâmetro do arame-eletrodo (Dg=De), diâmetro da gota menor que o diâmetro do arame-eletrodo (DgDe), mantendo a taxa de deposição fixa. A análise dos resultados obtidos revelou que a metodologia experimental empregada é efetiva na determinação das variáveis da corrente contínua pulsada para o arame tubular rutílico E71T-1M. De posse desta, foi possível produzir cordões de solda de bom aspecto superficial e morfológico, além de se obter boa estabilidade do arco (livre de respingos) quando utilizada uma Distância de Bico de Contato-Peça (DBCP) de 24 mm e diâmetro da gota (Dg) menor que o diâmetro do arame-eletrodo (De). Não obstante, quando empregada DBCP de 24 mm, foi observada uma significativa variação na energia de soldagem quando empregado diferentes diâmetros de gota, sendo obtidos os valores de 9,0 kJ/cm para Dg>De e 12,6 kJ/cm para Dg De), without changind the deposition rate. The analysis of the results showed that the experimental methodology used is effective to determine the pulsed current variables for the E71T-1M rutile tubular wire. Thus, it was possible to produce weld beads with good surface and morphological appearance, as well as good arc stability (without weld spatter) when using a 24 mm of distance from the nozzle to the workpiece (DBCP) and smaller droplet diameter (Dg) than the diameter of the electrode-wire (De). Moreover, when using DBCP of 24 mm, a significant variation in the welding energy was observed when different droplet diameters were used. About that, with Dg>De was obtained 9,0 kJ/cm and for Dg

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Pulsed current gas metal arc welding of P91 steels using metal cored wires

Cited by 16 publications

References 19 publications

Evaluation of Welded Joints in P91 Steel under Different Heat-Treatment Conditions

Evaluation of Welded Joints in P91 Steel under Different Heat-Treatment Conditions

Simultaneous Optimization of Joint Edge Geometry and Process Parameters in Gas Metal Arc Welding Using Integrated ANN - PSO Approach

Uma Contribuição na Determinação das Variáveis da Corrente Contínua Pulsada para o Arame Tubular E71T-1M

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