| 摘要 |
<p>Disclosed is a steel for machine structural use including 0.05-0.8% of C, 0.03-2% of Si, 0.2-1.8% of Mn, 0.1-0.5% ofAl, 0.0005-0.008% of B, and 0.002-0.015% of N, and including 0.03% of P or less (excluding 0%), 0.03% of S or less (excluding 0%), and 0.002% of O or less (excluding 0%), with the remainder comprising iron and unavoidable impurities. The ratio of BN/AlN precipitated in the steel is 0.020-0.2. Also disclosed is a case hardened steel component in which the ratio of BN/AlN deposited on the carburized or carbonitrided component surface is 0.01 or less and a manufacturing method for same. The steel for machine structural use exhibits excellent machinability in continuous cutting at high speeds using cemented carbide tools, and in interrupted cutting at low speeds using high-speed steel tools, as well as excellent impact performance, even after being subjected to a heat treatment such as quenching and tempering. Furthermore, the case hardened steel component exhibits excellent fatigue resistance, and particularly excellent pitting resistance.</p> |
