| 摘要 |
PURPOSE:To obtain ball-bearing steel combining high rolling fatigue strength and free-cutting by using, as a base, ball-bearing steel with a specific composition, incorporating Te and S to the above and limiting O content to a proper range. CONSTITUTION:The ball-bearing steel is an alloy consisting of, by weight, >0.60%-1.50% C, <=1.0% Si, <=1.5% Mn, <=4.0% Cr, <=0.10% Te, and <=0.40% S(where %Te/%S>=0.04, Te+S>=0.007%), and further, <=0.0030% O, <=2.0% Cu, <=1.0% Ni, >1.0-5.0% Mo, <=0.1% Al, <=3.0% W, <=2.0% Co, <=0.10%, in total, of REM, >=1 kind among <=0.30% Pb, <=0.30% Bi(where Pb+Bi<=0.30%), <=0.40% Se(where S+Se<=0.40%) and <=0.01% Ca and the balance Fe, in which globular sulfides are uniformly dispersed and the area ratio of alumina cluster is <=0.5%.
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