| 摘要 |
PROBLEM TO BE SOLVED: To provide case-hardening steel for machine structural use having excellent austenitic grain size characteristics in the case where carburizing or high concentration carburizing is carried out in a high temperature region of≥1,000°C by using, as a pinning grain, a precipitated grain different from conventionally used pinning grains. SOLUTION: In the case-hardening steel for machine structural use having excellent austenitic grain size characteristics, the ratio between Mn and S contained in the steel, Mn/S, is made to 0.6 to 1.4 by atomic ratio and the amount of the resultant sulfides composed mainly of MnS is made to 0.25 to 1.0 mass% and, further, fine sulfides of≥10,000 pieces/mm<SP>2</SP>are contained. COPYRIGHT: (C)2005,JPO&NCIPI
|
