| 摘要 |
PROBLEM TO BE SOLVED: To improve a fatigue life and corrosion resistance by providing martensitic stainless steel of specified composition which constituted the parts to keep the crystalline grain diameter at the specified value or under. SOLUTION: A carbon concentration is regulated in a specified range by substituting a part of nitrogen having the similar solid solution reinforcing effect for carbon which adversely affects the corrosion resistance, forms coarse eutectic carbide when the content is large, and degrades the function. At least one component of a rolling device formed of stainless steel including a roller bearing and a direct-acting bearing provided with a shaft body, or an inner ring 1, an outer ring 2 and rolling elements 3, is formed of martensitic stainless steel having the composition consisting of, by weight, <=0.6% C, 10-20% Cr, 0.1-0.8% Mn, 0.1-1.0% Si, 0.05-<0.2% N, <=3.0% Mo, <=1.0% V, <=7% Co, and the balance Fe, in which the relationship of C and Cr contents satisfies the inequalities of C%<=-0.05% Cr+1.41 and C+N>=0.45, and the mean grain diameter is <=20μm. The grain size becomes further smaller by adding 0.05-0.5% one or more of Ti, Nb and W.
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