Influencia de la soldadura semiautomática GTAW en la microestructura y propiedades mecánicas de juntas soldadas de aluminio A1200 - H14 usado en la industria carrocera

Abstract

The following research work was performed with the main objective of determining the microstructure and mechanical properties of an aluminum welded under the semi-automatic GTAW process. This welding process can be applied in the food industry, mechanical structures or the bodywork industry. Preliminary tests were carried out with different welding parameters, among these the voltage, amperage, preheating temperature and protective gas flow used in the process were regulated. The joints obtained were subjected to penetrating dye tests and visual inspection, thus finding the appropriate welding parameters and obtaining the best possible properties. The material worked with was the aluminium alloy A1200-H14 due to the relative ease of finding this product in the local market. The dimensions of the plates to be welded were 200x100x3mm. Once the welded material was obtained, destructive and non-destructive tests were carried out, such as: hardness tests, traction, visual inspection and penetrating inks to determine the mechanical properties of the material. With the different mechanical tests that were carried out it was possible to verify that the hardness of the material was increased with respect to that of the base material, the microstructure of the material was affected in such a way that the thermally affected zone presented a different colouring to that of the base material, while the tensile strength of the material was reduced by half, this due to the fact that a single weld seam was made on the plates. Meanwhile, the final microstructure was clearly affected after applying the welding process to the joints, where the clear difference between the base material and the weld bead made was observed, obtaining mainly an interdenritic type microstructure composed of SiAI2 crystals, chromium segregations due to the filler material used.