Sliding wear resistance and worn surface microstructure of nanostructured bainitic steel

This research studied the effect of austempering temperature on the sliding wear resistance of high-Si–Al steel, with a nanostructured bainitic microstructure obtained by austempering, and compared it with a tempered martensitic microstructure obtained by tempering. Results show that the sliding wear resistance of the nanostructured bainitic microstructure increases as the austempering temperature is decreased from 260 to 220 °C. The wear resistance of these austempered samples is 21–51%, greater than that of tempered ones, although austempered samples have a lower hardness than tempered ones. In addition, the worn surface microstructure of samples tempered and austempered at 240 °C was also examined, indicating that the single-phase α nanograins were formed in the worn surface of both samples. The mean size of nanograins, in the worn surface of samples austempered at 240 °C, is less than that of the tempered ones.