Studies on the application of hot-pressed silicon nitride ceramics as cutting-tools

Studies on the application of hot-pressed Si₃N₄ as cutting tool were carried out and satisfactory results achieved. In cutting hardened tool steels, chilled cast iron, pure molybdenum and pyrolytic graphite, the tool life of Si₃N₄ cutting tools is several times as long as that of sintered carbide tools. In threading, the Si₃N₄ cutting tool also performs satisfactorily. In order to test its cutting property under shock load, a milling test was made. The results show that the Si₃N₄ cutting tool can resist the shock load in milling. In cutting cast iron with high cutting speed, the Si₃N₄ cutting tool was also successful. These results indicate that hot-pressed Si₃N₄ is a cutting tool material which should be developed extensively.