Desgaste do aço inoxidável AISI 440BC na presença de misturas diesel-biodiesel utilizando dispositivo pino-sobre-disco

Abstract

With the development of the Brazilian Program of Biodiesel Production and Use (PNPB), many research groups have been studied the effectiveness of this fuel focuses on economical, technological, environmental and social aspects. The lack of information in the literature about the behavior of the AISI 440BC stainless steel in the presence of biodiesel and its blends is the main motivation of the present research. The aim of this work was to analyze the effect of biodiesel and diesel-biodiesel blends on the sliding wear behavior of the AISI 440BC martensitic stainless steel without lubrication (dry) and lubricated with the commercial diesel (B7 – diesel with 7% biodiesel), biodiesel (B20), biodiesel (B30), biodiesel (B50), and pure biodiesel (B100), in the following conditions: annealed, quenched and tempered at 100ºC and at 300ºC. The tests were performed on a pin-on-disc device, at a 1.8 m/s sliding speed, 14.7 N load, and 4400-m sliding distance, following the ASTM G99-04 Standard. The samples were characterized by optical microscopy (OM), scanning electron microscopy (SEM), dispersive energy spectroscopy (EDS) and X-ray diffraction (XRD), and by mechanical tests to determining the hardness, microhardness and wear, before and after heat treatments. The annealed material without lubrication presented the highest wear coefficient (k = 0.6667x10-2), while when lubricated with B50 presented the lower wear coefficient (k = 0.0370x10-2). The tempered and quenched at 100ºC material showed the following values: B20 (k = 0.0665x10-2), B30 (k = 0.0624x10-2), B50 (k = 0.0579x10-2), and B100 (k = 0.1462x10-2).The tempered and quenched at 300ºC material presented: B20 (k = 0.1077x10-2), B30 (k = 0.0458x10-2), B50 (k = 0.0576x10-2), and B100 (k = 0.0678x10-2). The results indicated a tendency to decrease wear with the use of biodiesel B100, and wear behaviors very similar among B7, B20, B30 and B50.