| 摘要 |
PROBLEM TO BE SOLVED: To produce inexpensive carburizing steel which can be subjected to high concentration carburizing treatment and consequently has excellent mechanical properties. SOLUTION: The carburizing steel having excellent mechanical properties has a composition containing, by mass, 0.1 to 1.1% C, 0.03 to 2.0% Si, 0.2 to 2.0% Mn, 0.002 to 0.1% S, 0.1 to 4.0% Cr, 0.005 to 0.06% Al and 0.002 to 0.03% N, and further containing one or more metals selected from 0.03 to 0.5% Ti, 0.03 to 0.5% Nb/2 and 0.03 to 0.5% V, and the balance Fe with inevitable impurities. By performing high concentration carburizing so as to control the concentration of carbon in the surface to 0.8 to 3.0%, carbides are finely dispersed into the carburizing layer on the surface, no carbides having a major axis of >=10μm are present, and the average carbide grain size is controlled to <=3μm.
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