| 摘要 |
PROBLEM TO BE SOLVED: To prolong the rolling fatigue life of a rolling supporting device used in lubrication with foreign matter included. SOLUTION: The inner ring and the outer ring of a deep groove ball bearing are made of a steel material containing by mass ratio, 0.1-1.2% C, 0.1-2.0% Si, 0.1-2.0% Mn, 0.1-4.0% Cr, no more than 2.0% Mo, no more than 2.0% V, and Fe as remainder and inevitable impurities, the material being subjected to a carburizing nitriding process, and then the material processed is over-cooled to the A<SB>1</SB>-transformation point or below so that ausforming is applied, and upon shaping into the specified shape, the ausformed material is again heated to a temperature equal to or above the A<SB>1</SB>-transformation point so that quenching and tempering treatment is applied. The obtained facial layer to serve as raceway has a total content C and N of 1.2-1.8 mass%, a hardness of HRC62 or more, a residual austenite amount of 25-40 vol.%, and an austenite crystal grain size of 5μm or less. COPYRIGHT: (C)2006,JPO&NCIPI
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