Comportamento de Juntas Soldadas de Aço C-Mn Obtidas Pelo Processo GMAW-RE com Eletrodo Rotativo

Abstract

Resumo O presente trabalho tem como objetivo estudar o comportamento de juntas soldadas obtidas pelo processo GMAW com eletrodo rotativo (GMAW-RE), de modo a permitir uma análise comparativa de produtividade e propriedades mecânicas com o processo GMAW convencional (GMAW). Foram realizadas soldagens multipasse pelos dois processos GMAW com preaquecimento de 100 °C em chapas de dimensões 500 × 150 × 10 mm em aço ASTM A36, na posição plana e energia de soldagem média de 2,30 kJ/mm. Após a soldagem, foram realizados ensaios de impacto Charpy-V, microdureza e metalográficos em corpos-de-prova removidos transversalmente ao cordão de solda. Adicionalmente, foi realizada uma análise comparativa de produtividade entre os processos. Os resultados mostram que o processo GMAW-RE propicia um aumento de produtividade e redução de custos significativos em relação ao processo GMAW. Adicionalmente, foram observados valores equivalentes de tenacidade ao impacto para o metal de solda, mas uma redução nesta propriedade na zona termicamente afetada. Embora a literatura disponível destaque o elevado potencial deste processo para substituição do processo GMAW convencional em aplicações industriais, verifica-se a necessidade de mais evidências experimentais para um maior suporte a esta indicação.

Influence of rotation frequency and rotation diameter on mechanical properties and microstructure of weld metal produced by MCAW-RE

“…19, it is clear that, regardless the less number of passes and higher level of dilution due to the adoption of square groove, the results obtained in the present work are within the same scatter band of the other multi-pass groove butt joints performed by GMAW process using cored wires [38,44,[73][74][75][76]. It can be explained by the radial movement of the arc which promotes a lower peak of temperature in the weld center line [81] and an improvement on the impact toughness [41].…”

“…First of all, in regard to the costs and productivity, it is important to remember that the conducted experiment in this work was performed with the intention to obtain a welded joint free of defects and, therefore, to test the potential of the process to reach the requirements of some current standards. This goal was achieved using equivalent heat inputs (Table 6), and particularly, the productivity was higher than that obtained by the conventional GMAW process [41], as expected [67].…”

“…It is seen in Fig. 11, where a superior dilution was found (26.6%) in comparison with that provided by GMAW process (19.3%) observed in previous work using solid wire [41], which can affect the phase transformation kinetics during weld-induced thermal cycles, as well as the resultant microstructures [39]. The chemical composition of the weld metal confirms the effect of dilution, where an increase in carbon content and reduction of others alloying elements in comparison with the proposed for "pure" weld metal.…”

“…1). Table 6 shows a comparison with some characteristics obtained from conventional GMAW process in previous work [41], where advantages of MCAW-RE process is clearly seen. Indeed, it is observed an increase of about 33% in productivity when compared with conventional GMAW process.…”

“…Although it could be recognized the relevance of the above discussion, it is worth noting that the main goal of this work is to study the mechanical and microstructural properties of the weld metals obtained by these processes, because the available data is limited and needs complementation [23,24,41].…”