| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel for case hardening exhibiting excellent crystal grain coarsening resistance, for performing case hardening treatment such as carburizing and carbonitriding in a shorter time, even in the case carburizing is performed at a temperature higher than that in the conventional example, and also having excellent cold workability as the stock, e.g., for rod-shaped machine parts such as a pulley for a CVT (continuously variable transmission) requiring carburizing depth and excellent workability. SOLUTION: The steel for case hardening having excellent crystal grain coarsening resistance and cold workability comprises a rolled steel in which the contents of C, Si, Mn or the like are specified, and further, the contents of N, Al and Ti are specified. The maximum value of the standard deviation in the variation of the Vickers hardness in the cross section of the steel is≤10, or further, the area ratio of ferrite+pearlite in the metallic structure is≥80%. Its production method is also provided. COPYRIGHT: (C)2007,JPO&INPIT
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