| 摘要 |
PROBLEM TO BE SOLVED: To improve the uniformity of the fracture face in an alloy at the time of punching by dispersing MnS having specified grain size therein in a specified ratio. SOLUTION: Into an Fe-Ni series alloy for a lead frame contg., by weight, 30 to 50% Ni, MnS having <=3μm grain size is dispersed in the ratio of 1,000 to 60,000 pieces/mm2. Preferably, it contains 0.1 to 1.5% Mn and 1 to 500 ppm S, and its cleanliness prescribed in JIS0555 is 0.006 to 0.03. Though Mn is one of deoxidizing components, it is bonded with S harmful for hot workability to form MnS, therefore, it is effective for the improvement of the hot workability. The preferable componential compsn. of the lead frame alloy is composed of 0.003 to 0.02% C, 0.05 to 1.0% Si, 0.1 to 1.5% Mn, 30 to 50% Ni, 0.0005 to 0.02% S, 0.001 to 0.02% N, and the balance Fe with inevitable impurities.
|
