The objective of this work was to optimize the operational conditions aiming to deposit weld overlays with a minimal dilution and iron content as low as possible, and a thickness of weld higher than 3 mm just in a single layer. The alloys studied were Inconel 625, Hastelloy C276 and Inconel 686. The ASTM A516 Gr 60 steel was used as substrate. The welds were performed by GTAW cold wire feed process. The Taguchi method was applied to design the experiments and to evaluate the influence of the variables. The results showed that the arc oscillation (weaving) has a strong effect on the penetration and dilution of welds. The confirmation test for the optimal settings indicated that the additive model of the Taguchi method was not only confirmed the excellent reproducibility, but also provides sufficient confidence in the factorial effects.
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Wave Arc Movement Influence on the Dilution Level and on Weld Bead Geometry Using TIG Welding Process with Automatic Cold Wire FeedingAbstract: This work aims to study the influence of arc waving in GTAW process with cold wire feeding deposited in single pass in order to use nickel-based alloys as coating to of petroleum and natural gas industries, where low dilution is needed to avoid reduction in corrosion resistance of the coatings. The welds were made using an robot workbench and a cold wire feeder system. The alloy used as filler metal was AWS ER NiCrMo-3 (Inconel 625) and the substrate was ASTM A516 Gr 60 steel plates. Welds were carried out with automatic cold wire feeding varying without arc waving and with triangular type arc waving. In addition the heat input was changed at three levels. The results showed that the use of arc waving has considerably influence on the geometry of the weld bead and the level of dilution. With use of arc waving the weld bead reinforcement was reduced and the width were increased, providing a better distribution of material on the workpiece surface, thereby reducing the reinforcement/width (R/W) ratio. This parameter indicates the degree of convexity of the weld bead. A high R/W ratio indicates that the degree of convexity may be excessive; thereby hampering an adequate overlap between the passes aiming to produce weld overlay without voids between them. Penetration and dilution showed similar behaviors, with significantly reduction under conditions where the arc waving was applied. These results show that the use of arc waving ensures a combination of low R/W ratio with low dilution, condition that is desirable to weld coatings.
O “Capacite-se” se refere a um projeto elaborado pelo Programa de Educação Tutorial da Universidade Federal do Ceará - Campus Russas voltado aos discentes dos cursos de ciência da computação e engenharia de software. Tal projeto visa habilitar os alunos para o mercado de trabalho e os auxiliar em disciplinas que exigam o conhecimento de software e ferramentas computacionais. O objetivo deste relato é apresentar como se deu a realização destas atividades e os resultados obtidos com os feedbacks dos participantes quanto a organização e aprendizado adquirido com o projeto. A análise dos resultados quantitativos consolidou o projeto, comprovando sua eficácia e possibilitando sua continuidade.
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