| 摘要 |
PURPOSE:To improve the suitability of an Fe-Ni alloy sheet as stock for a lead frame for IC to blanking and plating by subjecting the plate to annealing and temper rolling under specified conditions. CONSTITUTION:A cold rolled Fe-Ni alloy sheet consisting of 35-55wt% Ni, <=0.05wt% C, <=0.5wt% Cr and the balance Fe is used as stock for a lead frame for IC. The sheet is annealed by holding at 680-1,120 deg.C for 0.1-600sec in a nonoxidizing or reducing atmosphere. It is then subjected to cold temper rolling at a draft (R) represented by formula I (where T is the holding temp. during the annealing) to regulate the surface roughness Ra to 0.03-0.30mum and the surface roughness Rmax to 0.15-3.00mum. The stock is blanked to the shape of a lead frame and plated with Ag. At this time, the stock shows superior suitability to blanking and plating.
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