Friction tests were conducted on self-matched pairs of medium-carbon steel using a pin-disk tribometer in an ambient laboratory environment with and without wear-debris removal, in order to clarify the influence of wear debris on the tribological properties of steels that were exposed to magnetic fields. The wear debris and worn surface were observed and analyzed. In the case that the wear debris was removed, the vast majority of wear debris was large, scarce oxidation, and no agglomeration, the grooves of various shapes and discontinuities, and no oxide layer were formed on the worn surface, severe wear occurred throughout the friction process. When the wear debris was not removed, the wear debris became fine, agglomeration and oxidation, a debris layer was formed on the worn surface, and the wear mode transitioned from severe to mild occurred during friction process. The results reveal that the re-entering of wear debris into the friction area is essential for the formation of a wear-debris layer and that an anti-wear effect can be achieved via the wear-debris layer formed on the worn surface during the friction process with a magnetic field.

G95Cr18 stainless bearing steel is used to manufacture rolling bearings widely used in aviation and navigation fields. Twin carbide structure often appears in G95Cr18 stainless bearing steel structure and affects its material properties. This study adopts ball-block friction pairs to qualitatively discuss the influence of twin carbide structure of different degrees on the friction and wear performance of G95Cr18 stainless bearing steel under dry sliding conditions at room temperature and atmospheric environment. The results show that a slight twin carbide structure has only a little influence on the friction coefficient but can reduce the wear rate slightly, while a severe twin carbide structure can significantly increase the friction coefficient and wear rate. Thus, the existence of an optimal value for twin carbide structure was confirmed. The wear mechanism is mainly oxidation wear and abrasive wear, and the oxide produced by oxidation reaction during friction consists mainly of Fe₂O₃.