| 摘要 |
PROBLEM TO BE SOLVED: To provide a rolling member which has the longer life, superior abrasion resistance and superior seizure resistance, by optimizing a Si-Mn-based nitride. SOLUTION: For instance, a rolling element 3 has the Si-Mn-based nitride formed on its surface layer through carbonitriding or nitriding treatment. The surface layer is controlled so as to contain 0.2 wt.% or more nitrogen by concentration, contain Si-Mn-based nitrides of 1% or more but less than 10% by an area rate, and contain Si-Mn-based nitrides with sizes of 0.05 to 1μm in the number of 100 pieces or more in the area of 375μm<SP>2</SP>. The rolling element acquires high strength by increasing the amount of fine precipitates of the nitride and thereby shortening a distance between the Si-Mn-based nitrides. The rolling element acquires higher strength by using a steel which contains 0.3 to 2.2 wt.% Si and 0.3 to 2.0 wt.% Mn, while controlling a ratio Si/Mn to 5 or less, and which is carbonitrided, quenched and tempered. COPYRIGHT: (C)2008,JPO&INPIT |
