抄録
The wear tester was made by ourselves. Two cylindrical test pieces were subjected to friction in their flat planes. In preliminary test it was shown that there are eight kinds of surface appearances, and that the wear states change from the one to the other in the process. The effects of frictional speed on the wear at high temperature were studied. The following steels were employed for the test: carbon steel, high chromium ferrite steel, 18-8 stainless steel, piercer plug steel (used for the piercing tool of Stiefel-Mannesmann tube making machine) and hot working tool steel. As the testing condition, 6 speeds ranging from 0.07 m/sec to 1.19 m/sec and vertical load of 10 kg were adopted. There are 3 types of wear. The first is shown in carbon steel and other tool steels, the second in high chromium steel and the last in austenite steel. In the first we recognize the minimum wear at 400∼500°C and 0.20∼0.34 m/sec and the maximum at higher or lower temperature. In the second, at high speed and at high temperature, galling and seizing occur. The minimum occurs at 400∼500°C at all speeds. In the last, at lower speed and at high temperature galling and seizing occur. The minimum occurs at high speed. The oxide layer were studied both by the micro-structure and X-ray method. In the carbon steel, the minimum wear range has the 2 layers of oxides Fe3O4 and Fe2O3. Under severe conditions, a brittle FeO oxide layer is produced beside them. In the other two high chromium steel, the oxide layer consists of 3 types of oxides. These oxides are always tightly attached to the surface of the test pieces at high temperature. The surface state and wear are closely related to these oxide layer.
