| 摘要 |
<p>A low carbon free-cutting steel which has a chemical composition that C: 0.03 to 0.19 %, Si <= 0.10 %, Mn: 1.00 to 2.50 %, P: 0.01 to 0.12 %, S: 0. 26 to 0.63 %, Al <= 0.010 %, N: 0.0030 to 0.0250 %, O: 0.005 to 0. 035 %, Te: 0.002 to 0.100 % and the balance: Fe and impurities, and satisfies (Mn/S) >= 4.0. The above steel may contain one or more of 0.04 to 1.25 % of Cr, 0.04 to 0.60 % of Ni and 0.04 to 0.40 % of Mo. The above steel is "a free-cutting steel being friendly to the environment of the earth" since it is free of Pb, and, nevertheless, exhibits the machinability superior to that of a conventional Pb free-cutting steel, and further, exhibits the hot workability better than that of conventional Bi free-cutting steel, is free from the occurrence of a crack or scab, and is excellent in productivity, and thus can be suitably used as a raw material of soft small parts which do not need high strength.</p> |
