| 摘要 |
<p>A steel for a mold for use in molding a plastic which has a chemical composition, in mass %: C: 0.25 to 0.45 %, Si: less than 0.3 %, Mn: 0.5 to 2 %, S: 0.01 to 0.05 %, sol. Al: 0.02 % or less and the balance: Fe and impurities, has a two phase metal structure composed of 15 to 30 area % of ferrite and the balanced amount of pearlite, and exhibits an austenite grain size defined in JIS G 0551 of 3 or more. The steel may further comprises Cr up to 0.5 % and/or V less than 0.2 %. The steel for a mold combines good machinability and high thermal conductivity and can be produced at a low cost.</p> |
