ABSTRACT

This paper presents an evaluation of the influence of chromium content and the blend of chromium and niobium in Fe-Cr-C hardfacing alloys on the microstructure and properties that involve microabrasive wear resistance. Various studies have been carried out searching for conclusive information on this system under wear conditions, due to the different phases and properties presented by these alloys. These alloys associate carbides with a metallic matrix giving them high hardness and mechanical resistance.

For the realization of the experiments, commercial Fe-Cr-C alloys were obtained in the form of consumables (electrodes and wire) and applied as coatings on ASTM A36 carbon steel by means of SMAW and GMAW welding processes, respectively. In this case, two electrodes with addition of 25 and 45 percent by weight of chromium and a wire with 20 and 5 percent by weight of chromium and niobium, respectively, were used.

The microabrasion wear test was performed using the fixed rotating ball method and, as an abrasive, a diamond suspension of 3μm granulation. For this, four test specimens were used for each alloy. In order to calculate the wear coefficient, the average loss in volume was determined at pre-established time intervals, relating the result to the sliding distance.

Keywords
Niobium; Chromium; Wear resistance; Microabrasion; Rotating ball