| 摘要 |
PURPOSE:To improve machinability without deteriorating hot workability nor causing food sanitation problems, by adding, as free-cutting elements, Sn and Bi to an austenitic stainless steel. CONSTITUTION:As austenitic stainless steel excellent in corrosion resistance and machinability, a steel material which has a composition consisting of, by weight, <0.2% C, <2.0% Si, <10% Mn, 7.5-30.0% Cr, <40.0% Ni, 0.005-0.50% Bi, 0.005-0.70% Sn, 0.0005-0.10% B, <0.20% P, <0.40% S, <0.02% O, <0.10% N, and the balance Fe or further containing 1 or >=2 kinds among 0.005-0.50% Zr, 0.005-0.50% REM, <0.09% Ca, 0.05-0.5% Al, 0.05-3.0% Nb, 0.05-0.5% Ta, 0.05-2.0% Ti, and 0.05-0.5% V or <5.0% Mo and/or <4.0% Cu independently or in combination is developed. Since harmful Pb as free-cutting component is not contained in the above steel, free-cutting austenitic stainless steel free from food sanitation problems as well can be obtained.
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