Uma avaliação comparativa dos processos MIG/MAG e eletrodo tubular em termos de capacidade produtiva, geração de fumos e de respingos

Abstract

Considering the existing operation differences between two competing welding processes, FCAW and GMAW in terms of quality and productivity, the necessity of quantifying and pointing out the main characteristics of each process comes out. The objective is to supply relevant and useful information to users, allowing them to opt for the process that better suits there requirements. However, for a comparison between these processes to be fair and of practical value, operational differences must be considered and taken account of. Therefore, the comparison between the two processes was carried out in such a way as to produce results most relevant and applicable results. To achieve these, the experiment was carried out using the most widely used wires and shielding gases for each process, under the same current level, while covering a typical range of use, with the same deposition rate per unit length, and especially respecting the other welding parameters that are typical of each of the processes. Weldments were carried through using the wires E71T-1 and ER70S6 under the gas shielding of 100%CO2 and Ar+25%CO2, at different current levels, using bevelled plates when pertinent. It was looked to distinguish and to evaluate characteristics of each process that could influence directly in its operation, such as, productive capacity (melting and deposition rates) and fume generation rate and spattering. Dedicated tests to measure these characteristics were applied systematically. In general, the tubular wire used presented a higher deposition rate than the solid wire, yet with a bigger consumption of material to form same-size-beads. It was also observed that the tubular wire generates a higher level of spatter with bigger dimensions of that the solid one, as well as bigger production of fumes. The shielding gas with 100% of CO2 intensifies the generation of fumes and spatter for the two processes. However, if analyzed in terms of economic point of view, it is demonstrated that with the tubular wire is possible to carry through certain amount of weld in lesser time (bigger productivity), in what it weighs the biggest cost in function of the price of the products at the moment.