Caracterización de la soldadura del acero ASTM A588 mediante el proceso GMAW modificado con aporte de arenas ferrosas

Abstract

This project is based on the characterization of a new welding process called modified GMAW, which makes use of the electrode corresponding to MIG/MAG welding; but, instead of using protection gas, it uses a thick layer of a mixture composed by F7A2 flux and ferrous sands, in different concentrations. This investigation was carried out due to the lack of experimental studies about the properties that the ferrous sands contribute to the welding of structural steels, such as A588. Therefore, it was necessary to perform superficial and volumetric Nondestructive Testing, mechanical tests such as tensile test, hardness and side bending, analysis of chemical composition, scanning electron microscopy, etc. Based on these tests it was possible to determine that the mixture with the best characteristics is that in which only flux was added; and that the sample welded with 20% of ferrous sands does not have acceptable properties according by the normative used. Additionally, the specimens welded with this type of sands showed a different microstructural behavior, based on the fact that the use of ferrous sands, mainly due to the presence of titanium, stores a greater amount of heat in the weld and produces a slower cooling; so that soft annealing zones were produced, which is the reason why the joints welded with ferrous sands have less mechanical properties.