부산대학교 도서관

Laboratory and scaled-up experiments were performed to investigate the air oxidation mechanism during casting of the low alloy molten steel.Oxygen pick-up of 54ppm and the formation of fine oxide inclusions occurred at the casting stream surface in the laboratory air casting experiment. In the scaled-up air casting experiment, on the contrary, oxygen pick-up at the casting stream surface was negligible. But large amount of oxygen pick-up and the formation of Mn silicate inclusions were observed near the falling area of the casting stream. This may be due to the entrainment of air which exists in concave parts of the casting stream.The surface perturbance and the gas volume in convace parts of the casting stream increased with the increase of the length of the stream, though the surface perturbance was very slight just under the nozzle of the ladle.These results predict that air oxidation during casting can be better prevented by means of argon shrouding near the falling area of the casting stream.