Patent ID: 9090959
Filing Date: 2015-07-28
Classification: C21D,C22C,F16C

Abstract:
1. A bearing steel excellent in cold workability, satisfying: C: 0.95 to 1.10% (in terms of mass %, the same shall apply to the chemical components, hereinafter), Si: 0.10 to 0.30%, Mn: 0.1% to 0.40%, Cr: 1.00 to 1.50%, Ni: 0.05% or less (excluding 0%), Cu: 0.05% or less (excluding 0%), and Mo: 0.03% or less (including 0%), and the balance consisting of iron and inevitable impurities, wherein Si (boundary Si), Ni (boundary Ni), Cu (boundary Cu), Mo (boundary Mo), Mn (boundary Mn), and Cr (boundary Cr) included in a region (boundary region) from a boundary surface of spheroidal cementite to a position at 20 nm away in a base material satisfy the following ranges, respectively, and the circularity coefficient of the spheroidal cementite is 0.80 or more: boundary Si: 0.6% or less (excluding 0%), boundary Ni: 0.10% or less (excluding 0%), boundary Cu: 0.10% or less (excluding 0%), boundary Mo: 0.03% or less (including 0%), boundary Mn: 0.10% or less (excluding 0%), and boundary Cr: 0.9% or less (excluding 0%).