| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method of a case hardened steel excellent in cold forgeability and hardly generating coarsening crystal particles even with conducting a carburization treatment at high temperature.SOLUTION: There is provided a manufacturing method of a case hardened steel having a process of manufacturing a slab by hot processing a steel raw material, a process of a heat treatment of the slab and a process of manufacturing the case hardened steel by hot processing the heat treated slab, the steel raw material has a predetermined component composition and the heat treatment is conducted under where P defined by the following (1) formula satisfies the following formula (2). P=T(25+log t)(1) 4.00×10≤P≤4.30×10(2), where T:temperature (K) and t:time (h).SELECTED DRAWING: None |
