| 摘要 |
PROBLEM TO BE SOLVED: To provide a round steel bar superior in hot workability and suitable for bearing element parts. SOLUTION: The round steel bar for bearing element parts superior in hot workability includes 0.8-1.2% C, 0.2-2.0% Si, 0.2-1.5% Mn, 0.5-2.0% Cr, 0.005-0.025% P, 0.003-0.015% S, where P(%)+2S(%) are 0.020-0.040%, 0.01-0.05% Al, 0.005-0.012% N, Cu <=1.0%, Ni <=2.0%, and the balance Fe with impurities, and Ti <=0.002% and O(oxygen) <=0.0015% in the impurities, and the width of a region in which the Cr content exceeds 1.3 times of a Cr content in the whole round steel bar, in a segregation band existing in the region of the center of the cross section to (R/10), when the radius of the bar is defined as R, is 0.0003-0.003 times of the diameter of the round steel bar.
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