| 摘要 |
PROBLEM TO BE SOLVED: To provide a sulfur-containing free cutting steel which has machinability equal to or better than that of heavy-metal-containing free cutting steel without incorporating a heavy metal badly influencing the environment. SOLUTION: This sulfur-containing free cutting steel comprises 0.03-0.20 mass% C, 0-0.35 mass% Si, 0.30-2.00 mass% Mn, 0.01-0.15 mass% P, 0.35-0.65 mass% S, 0.0100-0.0350 mass%, O, 0.020 mass% or lower N, 0-0.005 mass% Al, 0.02-0.20 mass% Nb, at least either 0.05-0.50 mass% V or 0.02-0.20 mass% Ti, and the balance being Fe and unavoidable impurities; and the number of sulfide inclusions, which is the main non-metallic inclusions present in the steel, is 500-1,000/mm<SP>2</SP>. COPYRIGHT: (C)2003,JPO
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