| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a needle roller bearing rolling member and a needle roller bearing, which have improved durability by suppressing the occurrence of peeling, surface crack, breakage, and hydrogen brittle separation. <P>SOLUTION: The bearing ring 11 and a needle roller 13, constituting the thrust needle roller bearing 1, are each formed of steel which contains 0.3-0.4% C, 0.2-0.5% Si, 0.3-0.8% Mn, 0.5-1.2% Ni, 1.6-2.2% Cr, 0.1-0.7% Mo, and 0.3-0.8% V, and Fe and inevitable impurities in the rest, where V is Mo or more, the Mo and V sum is twice as much as Si or more, and the Cr, Mo and V sum is 2.3-3.5%. The hardness of a hardening treatment layer formed on the surface layer portion is Hv 700-780. The maximum grain size of carbide distributed in the hardening treatment layer is 10μm or smaller and the area rate is 7-25%. The internal hardness is Hv 500-600. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
