Rolling Wear Characteristics of Annealed Carbon Steels under a Dry Condition

A study has been made on the rolling wear characteristics of the annealed carbon steels as well as the change of the rolling contact surface under a metal-to-metal dry condition in air using an Amsler-type wear machine. The results obtained are as follows.(1) The first sharp wear increase took place in the initial period of friction and the subsequent sharp wear increase occurred after exceeding a certain number of revolutions. The number of revolutions which causes the shap wear increase depends on the materials and the load applied and increased with an increase in hardness of the materials and with a decrease in the applying load.(2) Prior to the sharp wear increase, the occurrence of fine pits or cracks was observed on the rolling contact surface, which disappeared after the sharp wear increase.(3) It is considered that the fine cracks are initiated in the neighborhood of the rolling contact surface and there is a definite relationship between the Hertzian stress and the number of revolutions where the sharp wear increase took place. These results would suggest a contribution of the fatigue-related factors to the dry rolling wear.