A pin-on-disk friction and wear test was conducted to test the critical load for serious dry sliding wear of Vanadis 4 Extra steel at a sliding speed of 0.691 m/s, at room temperature, 200 °C and 400 °C respectively. Using scanning electron microscopy (SEM) and an energy dispersive spectrometer (EDS), the wear surface morphologies, wear mechanism and reasons were analysed. Results show that: with increasing temperature, the critical load for serious wear of Vanadis 4 Extra steel first increased and then decreased. The critical loads leading to serious wear were 900 N and 800 N at room temperature and 400 °C, respectively, while, there was no serious wear at 200 °C at less than 1000 N. There were abrasive particles found under different loads: as the load and temperature increased, the formation of oxide films on the worn surface plays an decisive role in wear: when applying a load smaller than the critical load, oxide films can protect and lubricate the steel substrate, presenting slight oxidative wear; when applying a load greater than the critical load, oxide films on the worn surface were ruptured and spalled, with mainly oxidative delamination wear being observed.