Patent ID: 6605163
Filing Date: 2003-08-12
Classification: C21D,C22C,H01J

Abstract:
Process for manufacturing a strip made of a &ggr;â€² and/or &ggr;â€³ structural hardenable Feâ€”Ni alloy, the thermal expansion coefficient between 20Â° C. and 150Â° C. of which is less than 7 Ã—10 âˆ’6/K, in which:a hot strip is manufactured either by hot rolling a semi-finished product or by direct casting of a thin strip which is optionally lightly hot-rolled, and the hot strip is subjected to a softening annealing operation consisting of a soak between 950Â° C. and 1200Â° C. followed by rapid cooling and optionally to a pickling operation, in order to obtain a softened strip; a cold-worked strip is manufactured by cold rolling the said softened strip, with a reduction ratio of greater than 5%; and the cold-worked strip is subjected to a recrystallization annealing operation in an inert or reducing atmosphere, carried out either on the run at a temperature between 900Â° C. and 1200Â° C. with a residence time of between 30 s and 5 mm, or statically with a soak at a temperature of between 900Â° C. and 1050Â° C. for a time of between 15 mm to 5 h, followed by cooling down to a temperature below 500Â° C. at a cooling rate sufficient to prevent the formation of hardening precipitates, wherein the temperature of the softening annealing carried out after the hot rolling is between 1000Â° C. and 1075Â° C.