Evaluation of wear resistance of a novel carbide-free bainitic steel

The effect of isothermal transformation temperatures on wear performances of a newly designed high-silicon carbide-free bainitic steel was studied. Wear tests were performed by a ball-on-disc tribometer using steel spheres as counterpart material. Friction coefficient was provided by the equipment, whereas wear rate was evaluated by the wear volume. Wear tracks on disc surfaces and worn cross-sections were analysed by means FEG-SEM, EDS measurements, XRD, roughness, and hardness tests. Bainitic microstructure offers better wear resistance compared to pearlitic-ferritic microstructure due to higher hardness, strain hardening capability, and strain-induced transformations. Adhesion and tribo-oxidational wear are the main wear mechanisms; the extent of oxidation increases increasing austempering temperature and it is maximum for samples treated at 350 °C and pearlitic-ferritic microstructure.