| 摘要 |
<p>A steel for a bearing, characterized in that the steel has a chemical composition in mass %: C: 0.95 to 1.10 %, Si: 0.15 to 0.70 %, Mn: 1.15 % or less, Cr: 0.90 to 1.60 %, P: 0.025 % or less, S: 0.025 %, O: 0.0012 % and the balance: Fe and inevitable impurities (S and O are elements forming non-metallic inclusions), in that the maximum diameter of oxide type non-metallic inclusions is more than 10 νm and not more than 15 νm in the case of an examination area of 320 mm2 and the number of inclusions having a diameter of a corresponding circle of 3 νm or more is 250 or less in the case of an examination area of 320 mm2, and in that the steel contains 0.020 mass % or less of AlN and/or the number of sulfide type non-metallic inclusions having a thickness of 1 or more is 1200 or less in the case of an examination area of 320 mm2. The steel for a bearing can be produced without the use of a special secondary refining process at a low cost and also has a long life, and thus can be used for general use. (νm)</p> |
