Análise do desgaste abrasivos em revestimentos duros soldados com arame tubular sobre aço de alta resistência

Abstract

Este trabalho teve como objetivo avaliar a resistência ao desgaste abrasivo de revestimentos duros aplicados por soldagem, utilizando arames tubulares das ligas FeCrC (60), FeCrC-Nb (68) e FeCrC-NbW. O processo empregado foi a soldagem FCAW, em corrente contínua, com modos de transferência spray e globular, sobre chapas de aço VC131. A metodologia incluiu a deposição dos cordões de solda, ensaios de desgaste conforme a norma ASTM G65-91, além de análises de morfologia, diluição, microestrutura e microdureza. Os resultados mostraram que o arame 68 (FeCrC+Nb) apresentou o melhor desempenho em resistência ao desgaste, seguido pelo arame 70 (FeCrC+NbW), enquanto o arame 60 (FeCrC) obteve o pior resultado. Em todas as condições, foram observadas trincas perpendiculares ao cordão, independentemente da energia utilizada.This study aimed to evaluate the abrasive wear resistance of hardfacing coatings deposited using tubular wires of the alloys FeCrC (60), FeCrC-Nb (68), and FeCrC-NbW, with a diameter of 1.6 mm in a single coating layer. The deposition was carried out with the FCAW (Flux Cored Arc Welding) process, operating in direct current (DC) and using two transfer modes: spray and globular. As substrate, VC131 steel plates with dimensions of 100 × 50 × 10 mm were used. For the wear test, five overlapping weld beads (40% overlap) were deposited on one end of the plate to form a coating. A specimen measuring 25 × 75 mm was extracted from the central region and subjected to wear testing using a rubber wheel abrasion tester, standardized by ASTM G65-91, to obtain mass loss values. On the other end of the plate, a single bead was deposited for evaluation of morphology, dilution, microstructure, and microhardness. Morphological analysis was performed through macrographs of the bead’s cross-section, followed by dilution calculations. Microstructural analysis was conducted using micrographs of the bead’s cross-section, and microhardness was measured through indentations on the same section. All depositions were carried out with the aid of a welding manipulator to ensure control of the process parameters. The results showed that wire 68 (FeCrC+Nb) achieved the best performance in terms of wear resistance, followed by wire 70 (FeCrC+NbW), with very close results. Wire 60 (FeCrC), compared to the others, showed the lowest performance. All wires used in this experiment exhibited cracks perpendicular to the bead, regardless of the energy condition applied.