Hardened Fe-Ni alloy for the manufacture of integrated circuit leaderframes and manufacturing process

The present invention relates to a hardened Fe-Ni alloy and to a process for manufacturing it in the form of thin strip that can be especially used for the manufacture of integrated circuit leadframes or of electron gun grids for color display cathode-ray tubes. A method of making a Fe-Ni strip whose chemical composition comprises, by weight: 36% Ni+Co 43%; 0% Co 3%; 0.05% C 0.4%; 0.2% Cr 1.5%; 0.4% Mo 3%; Cu 3%; Si 0.3%, Mn 0.3%; the rest being iron and impurities, the alloy having an elastic limit Rp0.2 more than 750 Mpa and a distributed elongation Ar more than 5%. The alloy is optionally recast under slag. The strip is obtained by hot-rolling above 950° C., then cold-rolling and carrying out a hardening treatment between 450° C. and 850° C., the hardening heat treatment being preceded by a reduction of at least 40%. The invention is useful for making integrated circuit support grids and electronic gun grids.