This paper attempts to answer the question why soft abrasives can sometimes were hard materials. The hardened 35Mn2 steel specimens were tested with a rubber wheel testing apparatus. Different results were obtained at different velocities. At a high velocity, various shapes of tongues on the worn tracks and wear debris were found. The debris can be classified as one of three kinds: spherical, debris with round edges, and chip-like. The appearance of debris and tongues indicates that during the wear process, frictional heat accumulated on the metal surface, the surface layer was softened and even fused so that its hardness drastically decreased, and wear occurred. In this case, soft-abrasive wear has transformed into hard-abrasive wear. Measurements of high temperature hardness indicate that the transformation point, at which the hardness of the specimen decreased to that of the coal used as the abrasive, is about 830°C. A suggestion is also provided for selection of wear-resistant materials.