| 摘要 |
<p>This invention provides a low carbon sulfur free-machining steel that has machinability favorably comparable with Pb free-machining steels and Pb-added composite free-machining steels in relatively low-speed cutting using HSS tools, has excellent carburizing properties and continuous casting properties, and is suitable as materials for soft small components such as automobile brake components, components for peripheral devices in personal computers and components for electrical machineries and apparatuses. The low carbon sulfur free-machining steel comprises C: 0.05 to less than 0.20%, Si < 0.02%, Mn: 0.7 to 2.2%, P: 0.005 to 0. 25%, S: more than 0.40 to 0.60%, Al < 0.003%, O: 0.0090 to 0.0280%, and N: 0.0030 to 0.0250% with the balance consisting of Fe and impurities. The steel optionally comprises one or more of Te, Sn and Se and/or one or more of Cu, Ni, Cr and Mo. The impurities comprise Ca 0.018 and 2.5 < Mn/(S + O) < 3.5.</p> |
