Deposição de ligas Fe-Mn-Cr-Si-B por plasma PTA

Abstract

The search for cost reductions within the most varied industrial sectors is constant. Optimizing the service life of parts and machinery, for example, is one of those cases in which the economic benefit is high. Alloys with high mechanical resistance have been used as coatings, so as to overcome problems related to equipment wear. One of these alternatives is the plasma transferred arc (PTA) technique, where the addition material used is in the form of powder. It is a very promising process, as it allows the mixing of alloys, increasing its range of application. The possibility of using specific alloys seeking exclusive features, however, also brings with it divergences and challenges in the optimization of welding parameters for each case. Therefore, the objective of this study was to evaluate the influence of welding parameters on the microstructure and mechanical properties of Fe-Mn-Cr-Si-B alloy coatings. The varied parameters were the pulsed welding current and powder feed rate. Analyzis were performed using an optical microscope and a scanning electron microscope (SEM), as well as evaluating the microhardness of the coating. The results obtained showed that the current intensities chosen were not sufficient to melt the amount of powder used next to the substrate in a homogeneous way, with very low or null dilution values and the presence of pores. The microstructures were more refined and defined in the coatings with lower pulsed current, not providing high variations in the hardness of the coatings.