Estudo de condições de soldagem para soldagem com arame tubular auto protegido: efeitos de correntes de ar e DBCP.

Abstract

The aim of the present work was to evaluate the influence of wind and welding parameters on the welding characteristics of ASTM A36 steel using an AWS E71T-11 electrode in the Flux-Cored Arc Welding (FCAW) process. After welding test and set parameters, eight ASTM A36 steel plates were cut and weighed before and after welding to evaluate the deposited mass. The welds were performed in constant tension mode, with and without the influence of air flow, varying the CTWD and the travel speed to verify its effects on the yielded, geometry and dilution of the weld bead, as well as microstructure and hardness of the melt zone and HAZ. The inclusions formed into the molten zone were also evaluated qualitatively and quantitatively. Samples of the weld beads in cross section were cut and prepared metallographically. Macrographs of the specimens were taken and the geometry of the weld beads were measured. The microstructures were evaluated, after metallographic preparation, by using a light microscope and scanning electron microscopy (SEM). A microhardness profile, from the melted zone to the base metal, was performed in each specimen using an automatic microhardness tester. It was concluded, for this work, that the presence of external air flow did not present statistically significant interferences in the weld beads, but presented a significant increase in the number of inclusions. The CTWD presented a statistically significant influence, only in the dilution that reduces with the addition of that one. Finally, the welding energy influenced the weld bead, as well as altered the microstructure and hardness, influencing the also presence of inclusions in the molten zone.