Role of oxidation in the mild wear of steel

Abstract

The structures of the wear debris obtained in several investigations into the mild wear of steel, i.e. the wear of relatively smooth steel surfaces, are compared with those to be expected from the results of representative oxidation experiments. It is assumed that sliding and stress have no effect on the oxides formed. Whilst this assumption is questionable on the grounds that surface conditions can have a large effect on certain features of oxidation, the comparison made on the basis of this assumption does, in fact, reveal a high correlation between the oxides actually obtained in the wear experiments and those to be expected from the oxidation data of Davies, Evans, and Agar and of Moreau and Bardolle, provided it is further assumed that oxidation occurs at the `hot-spot' temperatures predicted from Archard's curves for single-contact wear conditions. The tentative conclusions to be drawn from this correlation are examined in relation to the most probable method of oxide growth at a contacting asperity, and its removal to form a wear particle. A partly confirmed prediction regarding the variation of wear rate with speed is then made on the basis of these conclusions.