Characterization of the underwater welding arc bubble through a visual sensing method

Wang, Jianfeng; Sun, Qingjie; Zhang, Shun; Wang, Chengjin; Wu, Laijun; Feng, Jicai

doi:10.1016/j.jmatprotec.2017.08.019

Cited by 50 publications

(25 citation statements)

References 30 publications

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“…A medida que os gases são desprendidos, pela queima do fluxo do arame autoprotegido, as bolhas crescem. De acordo com Wang et al (2018), a força de retenção na bolha é maior do que a força de destacamento e o volume da bolha é drasticamente aumentado, enquanto ela está retida na superfície da poça de fusão.…”

Section: Análise Das Filmagensunclassified

Investigação do Fenômeno das Bolhas em Soldagem Subaquática Molhada com Arame Tubular Autoprotegido

Mendonça

Bracarense

2019

Soldag. insp.

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Resumo O fenômeno de formação de bolhas está fortemente ligado a variação dos sinais elétricos e estabilização do arco de solda na soldagem subaquática molhada com arame tubular (FCAW). O bom entendimento desses fenômenos pode ser usado para uma melhor otimização dos parâmetros de soldagem e consequentemente uma melhoria na qualidade final da solda. Com este trabalho observou-se o comportamento dinâmico das bolhas formadas, uma possível relação de mudança de frequência e do tamanho das bolhas geradas com a mudança dos parâmetros de soldagem. Analisou-se ainda a ocorrência dos modos de evolução de bolhas e sua correlação com os valores dos sinais elétricos, e a comparação da formação de bolhas com um diferente tipo de tocha com a qual é possível utilizar bico de contato mantido seco e molhado. A formação de bolhas se mostrou um fenômeno instável e a geometria da bolha está em constante mudança. Assim, por meio do controle dos parâmetros de soldagem percebeu-se que é possível otimizar um tamanho de bolha ideal para melhorar a proteção do arco elétrico e evitar a sua extinção.

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Section: Análise Das Filmagensunclassified

Investigação do Fenômeno das Bolhas em Soldagem Subaquática Molhada com Arame Tubular Autoprotegido

Mendonça

Bracarense

2019

Soldag. insp.

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“…Attempts to reduce the imperfections in welded joints made in the water are made in different ways. Much attention is devoted to improving the stability of the welding arc in underwater conditions and assessing the metal transfer in the welding arc, using the following methods: visual sensing [15], in situ imaging [16], mechanical constraints [17], and ultrasonic waves [3,8]. The other research trend is developing filler materials for welding: modifying the flux coating and wires of coated electrodes [18] and applying a waterproof coating [19].…”

Section: Introductionmentioning

confidence: 99%

Role of Bead Sequence in Underwater Welding

2019

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This paper presents examinations of the role of the bead sequence in underwater welding. Two specimens of wet welded layers made by covered electrodes with the use of normalized S355G10+N steel were welded by a reasonable bead sequence. For each specimen, metallographic macro- and micro-scopic tests were done. Then, Vickers HV10 hardness measurements were conducted for each pad weld in the welded layer. The results show that welding in the water environment carries many problems in the stability of the welding arc, which influences the properties of the welds. The effects of refining and tempering the structure in heat-affected zones of earlier laid beads was observed, which provides a reduction of hardness. The possibility of applying two techniques while welding the layer by the wet method is described. It is stated that a reasonable bead sequence can decrease the hardness in heat-affected zones up to 40 HV10. Tempering by heat from next beads can also change the microstructure in this area by tempering martensite and can decrease susceptibility to cold cracking.

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“…Welding in underwater environment is most often applied as a method of repairs water constructions. The process is most often carried out with direct contact with water (wet welding) with the use of covered electrodes Wang et al, 2018). Water environment intensifies some problems that have a negative impact on weldability of steel, such as a rapid cooling rate (Guo et al, 2017;Tomków et al, 2018a;Sajek, 2019) and the presence of residual stresses (Aloraier et al, 2004;Hu et al, 2017;Han et al, 2019;Wang et al, 2019a;Wang et al, 2019b).…”

Section: Introductionmentioning

confidence: 99%

Efecto del sistema de apantallamiento de la soldadura y el tiempo de almacenaje de los electrodos en el contenido de hidrógeno difundido en el metal depositado

et al. 2019

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In the study the glycerin displacement method was used for determination of diffusible hydrogen content in deposited metal. Specimens were welded in the air and in the water with covered rutile electrodes. The first part of the specimens was made immediately after opening the package of the electrodes. The electrodes were then stored in opened packages in laboratory conditions that allowed for contact with the air for three years. After that time, the second part of the samples was made. The results of the measurements of the diffusible hydrogen amount in deposited metal ranged from 32.61 to 39.95 ml/100 g for specimens welded in the air and from 51.50 to 61.34 ml/100 g for specimens made in the water. The statistical analyses were performed in a Statistical software package using the ANOVA module (one-way analysis of variance) with an assumed significance level α = 0.05. The assumption of normality was verified by the Shapiro-Wilk test. The homogeneity of variance was verified by the Levene test. In the next step, post-hoc analyzes were made. The aim was to determine which averages are significantly different. Scheffe, Tukey, NIR Fisher, Newman-Keuls and Duncan tests were used. Possible changes in the diffusible hydrogen content in deposited metal resulting from storage time of electrodes (3 years) were verified by Student's t-test. All of the statistical analysis shows that the storage time of the electrodes has no significant influence on the diffusible hydrogen content in deposited metal regardless of the welding environment.Citation/Citar como: Tomków, J., Fydrych, D., Rogalski, G., Łabanowski, J. (2019). "Effect of the welding environment and storage time of electrodes on the diffusible hydrogen content in deposited metal". Rev. Metal. 55(1): e140. https:// doi.org/10.3989/revmetalm.140

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Characterization of the underwater welding arc bubble through a visual sensing method

Cited by 50 publications

References 30 publications

Investigação do Fenômeno das Bolhas em Soldagem Subaquática Molhada com Arame Tubular Autoprotegido

Investigação do Fenômeno das Bolhas em Soldagem Subaquática Molhada com Arame Tubular Autoprotegido

Role of Bead Sequence in Underwater Welding

Efecto del sistema de apantallamiento de la soldadura y el tiempo de almacenaje de los electrodos en el contenido de hidrógeno difundido en el metal depositado

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