Deposição de revestimento AISI 317L contra corrosão por processo GTAW mecanizado com adição de arame frio.

Abstract

The present work aims to investigate the corrosion resistance of austenitic stainless steel coatings applied on carbon steel substrate via mechanized GTAW process with the addition of cold wire (GTAW-MAF). The welds were carried out using AISI 317L steel wires with a diameter of 1.2mm as the filler metal. For the isolated welding beads, a linear factorial design experiment was designed with three independent variables (current, feed speed and electrode/part distance) and with the addition of central and axial points (23+6+3), totaling 17 tests . The response variables analyzed were dilution (%), wettability (°), height and width of beads (mm), selecting the three parameters with the best operational feasibility to be used in the coating process. In the welding coatings process, two techniques were used: with and without substrate preheating. Preheating proved to be effective in reducing discontinuities between weld beads and it was possible to develop a viable and replicable technique for the deposition of AISI 317L coating via the GTAW-MAF process. It was found that the deposition process used provided coatings with chemical composition similar to those of the addition material used and that the best results in corrosion resistance and dilution were given when using welding currents above 220A, feed speed between 4m/min and 5m/min and electrode-to-part distance of 10mm. The R2T2 coating showed good dilution results (10.38%), resistance to polarization 2.8x greater in relation to the substrate, little presence of inclusions and good operational regularity in the deposition of beads with low presence of discontinuities.