Dry sliding wear of ductile and austempered ductile iron: effect of load and sliding speed

Abstract

In this study, dry sliding wear behaviour of a copper alloyed austempered ductile iron (ADI) consisting of very fine ausferrite, small high carbon austenite blocks, was investigated against 100Cr6 ball using ball-on-disc tribometer. Tribotests were conducted at different loads of 10, 30, 50, and 100 N and speeds between 0.39 to 0.79 m/s. Worn-out surfaces and wear debris revealed tribe-oxidation and abrasive wear as the primary mechanism for material removal at lower loads and low speed (0.39 m/s). With an increase in load and speed, fragmented graphite nodules acted as solid lubricants. Additionally, partial transfer of tribo-oxide onto the counter-body ball, and plastic deformation and strain hardening of ADI matrix lowered the friction coefficient and wear rate at higher loads and speed, to nearly 1/ 3 and 1/10 as compared with those at lower loads and speed. The superior wear resistance of present ADI is worthy of consideration for transmission parts.