Abstract
In the previous report it is shown that the wear at high temperature is closely related to oxidation. The results of wear tests of carbon steel in air and in vacuum were compared with each other. The effects of frictional speed and surface load on the wear in vacuum are examined. At room temperature, wear loss in vacuum is smaller than in air, but at high temperature this relation is reversed. The hard layer on the surface of the test pieces in vacuum test is believed to reduce the wear loss. The hardness of this hard layer is about 900∼1000 of Micro-Vickers hardness. The cause of this hard-layer formation will be reported later. The effect of speed on wear loss in vacuum is ascribed to the temperature rise at the surface. Wear loss decreases with increasing speed. Increase of the surface load yields the hard layer at an earlier stage. So the load-wear loss curve shows one maximum and one minimum. The former is due to the thickening of the hard layer and the latter to the rise of surface temperature.
