Effect of martensite volume fraction and tempering time on abrasive wear of ferritic ductile iron with dual matrix

The effect of martensite volume fraction (MVF) and tempering time on the abrasive wear of ferritic ductile iron with a dual matrix structure (DMS) was investigated. Specimens were partially austenitized in the two-phase region (α + γ) at temperatures of 795 and 815 °C for 20 min and then quenched in oil held at 100 °C to obtain different MVF. The specimens were subjected to tempering at a temperature of 500 °C for 1 and 5 h. Some specimens were also conventionally heat-treated (austenitized at 900 °C and then quenched + tempered) for comparison. Samples were tested for tensile strength, ductility and abrasive wear. The results showed that weight loss resistance and strength increased and ductility decreased with increasing MVF. At constant MVF (∼25 or 62%), weight loss increased with increasing tempering time. The lowest weight loss was obtained for the conventionally heat-treated sample having ∼90% MFV, while the highest weight loss was observed for the sample having ∼25% MFV. Moreover, the weight loss increased with increased applied load for all tested samples. Abrasive wear was predominant for the conventionally heat-treated sample while adhesive wear was observed for the dual matrix structure, but only slight changes occurred with increased tempering time.