| 摘要 |
PURPOSE:To provide a bearing steel having a long service life for which the coarsening of austenitic crystalline grains is prevented. CONSTITUTION:This steel contains, by weight, 0.65 to 0.90% C, 0.15 to 0.50% Si, 0.15 to 1.00% Mn, 2.0 to 5.0% Cr and 0.0090 to 0.0200% N and furthermore contains one or two kinds of 0.010 to 0.050% Al and 0.005 to 0.50% Nb, and the balance Fe with inevitable impurities. As necessary, one or >= two kinds among 0.20 to 0.50% Ni, 0.10 to 2.00% Mo and 0.05 to 1.00% V may be incorporated. In such a manner, the content of C is reduced and, furthermore, the formation of harmful white layers is prevented by the effect of suppressing the diffusion of carbon atoms mainly by the incorporation of Cr to prolong its rolling service life and the coarsening of austenitic crystalline grains is prevented by Al, Nb and N. |
