Abstract
Pin-on-disk type friction and wear tests of a mild steel in contact with itself were carried out under unlubricated conditions in wet air to investigate the effects of changes in load on the transition between severe and mild wear. After the formation of heavily work-hardened wear surfaces under severe wear at first, the surfaces are oxidized under mild wear conditions at a low load, and then the wear mode changes to quasi-mild wear of low rate even under a high load at the next steps.
