| 摘要 |
PURPOSE:To manufacture a metallic sheet for a high strength lead frame at a low cost by incorporating specified amounts of Cr or Mo into an alloy having a specified compsn. constituted of Cu and Fe, casting it into a metallic sheet by high speed cooling, subjecting the metallic sheet to acid pickling treatment and thereafter executing specified cold rolling. CONSTITUTION:An alloy constituted of, by weight, 20 to 95% Cu and the balance Fe with inevitable impurities is incorporated with Cr and/or Mo in the range satisfying structural inequalities A and B and, if required, is furthermore mixed with <=8% Si, Al, etc., and <=2% C cr B. This alloy is cast into a metallic sheet at >=100 deg.C/sec surface cooling rate. Next, this alloy metallic sheet is subjected to acid pickling treatment to remove a surface oxidized film and to subject an iron phase to selective etching. After that, the metallic sheet is subjected to primary cold rolling at >=50% draft, is thereafter subjected to annealing and aging treatment and is then subjected to secondary cold rolling at 5 to 50% draft. After that, the rolled sheet is plated with copper according to necessary. In this way, the metallic sheet for a high strength lead frame can be obtd., and, if required, silver plating is obviated to permit the bare bond of a gold-copper wire. |
