Rolling device
AssigneeNtn Corporation
InventorsNoriaki Miwa, Yukio Matsubara
Life of this patent
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Abstract
Provided is a rolling device in which hydrogen is not easily accumulated within a roller element made of steel, such as an inner race and an outer race, and premature separation due to hydrogen embrittlement is prevented from occurring. A rolling bearing 1 having an inner race 2, an outer race 3, and rolling bodies 4, and at least one selected from the inner race 2, the outer race 3, and the rolling bodies 4 is made of predetermined steel. At least a part of oxide-based inclusions included in the steel is covered by MnS, and a ratio of a number of oxide-based inclusions covered by MnS is over 40% of a total number of oxide-based inclusions having maximum diameter of 3 μm or greater in the steel.
Claims11
A rolling device having a roller element made of steel, wherein at least a part of oxide-based inclusions included in the steel of the roller element is covered by MnS, and a ratio of a number of oxide-based inclusions covered by MnS is over 40% of a total number of oxide-based inclusions having maximum diameter of 3 μm or greater in the steel constituting the roller element,
- wherein the steel is an ignot casting, and
- wherein an element composition of the steel is such that C is no smaller than 0.95 mass percent and no greater than 1.1 mass percent, Si is smaller than 0.35 mass percent, Mn is smaller than 0.5 mass percent, S is smaller than 0.025 mass percent, Cr is no smaller than 1.4 mass percent and smaller than 1.6 mass percent, and remaining elements are iron and impurities.
Dependencies are inferred from the claim text.