As limited results were reported in terms of the evolution of sliding friction with growth of oxide layer in thickness during running-in, a pin-on-disc wear test was carried out in this study. 4.8Ni-1.Cr cast iron as core layer and low carbon steel as outer layers, were thermo-mechanically processed via three different routes. For samples with lower hardness due to their predominantly austenitic or martensite retarded matrices, we found that initially rapid increase of thickness of oxide layer continually lowers the sliding friction. However, after the oxide layer was beyond a certain thickness, the sliding friction began to increase consecutively. After a fluctuation of friction caused by the break-down of oxide, a mild equilibrium wear with roughly constant friction followed.