抄録
he present study was made with a view to improve the properties of the surface of rolled carbon steel. This report treats of the results of fundamental experiments made on the influences of heating conditions, sorts of steel and alloying elements on the oxidation of carbon steel (C 0.06-0.40%) at high temperature in the air and on the surface state of carbon steel. The oxidation degree at high temperature increased with lowering of heating rate. Rimmed steel was more easily oxidized than kileed steel at high temperature. Effect of Si, C and Cu on oxidation rate of steel was recognized, but that of C and Cu was lower than in the case of Si. The process of forming scale on the surface of carbon steel was as follows: the blackish cloud on metal surface occurred due to oxide film formed at about 400°C and this film grew into black thick oxide film containing 54-63% FeO, then somewhat swollen thin scale mainly of Fe2O3 developed on the film grew into bluish black thick scale containing 41-42% FeO and thin scale sticks to the surface of the thick scale. The Ni and Cu in steel formed an alloy-layer remaining on the surface of steel withont causing any oxidation. An empirical formula showing the relation between temperature and oxidation degree of the samples at heating rates of 20° and 6°C/min was obtained, and the formula showing the interrelation among Cu and Ni contents in steel, oxidation degree and thickness of alloy-layer was presented.
