Per: ANDRE CAETANO MELADO (IFES ), Gabriel Gonçalves Florêncio (IFES), Estéfano Aparecido Vieira (IFES), Hélio Goldenstein (USP)
Abstract:
In this work, the microabrasive wear resistance of a ductile iron, with commercial chemical composition, subjected to a heat treatment of quenching and partitioning was evaluated. The treatment consists of heating the material to 880ºC for a time of 2 hours, for complete austenitization, followed by quenching in oil to a temperature of 140ºC, intermediate to the temperatures Ms and Mf, to form a controlled amount of martensite. Then, the material was reheated to 300 and 375ºC (partition treatment) for different times (15, 60 and 120 minutes), and was subsequently cooled in air to room temperature. Optical microscopy (OM) and scanning electron microscopy (SEM) techniques were used for the microstructural characterization of the material obtained. The microabrasive wear test was of the “free sphere” type. The results showed a gain in wear resistance of the heat-treated material. A low carbon enrichment in austenite, in the partitioning step, can lead to the formation of brittle martensite and a reduction in microabrasive wear resistance. The longer partition times produced more wear-resistant microstructures at both temperatures tested in this work.