Process for manufacturing a foil of ferritic stainless steel having a high aluminum content, aluminum-containing ferritic stainless steel, and catalyst support useful for a motor-vehicle exhaust

A process for manufacturing a foil of ferritic stainless steel having an aluminum content, comprising hot rolling and cold rolling a ferritic stainless steel sheet having a composition comprising:

• iron
• 0.005%<carbon<0.060%
• 10%<chromium<23%
• 0.1%<aluminum<3%
• 0.003%<nitrogen<0.030%
• 0.1%<manganese<2%
• 0.1%<silicon<2%
• rare-earth elements in a proportion of between 0.03% and 0.15%, to a thickness of less than or equal to 1.5 mm, and then subjecting said steel sheet to the following treatments in the following order:
• a softening annealing treatment at a temperature of between 600.degree. C. and 1200.degree. C.,
• plating between two sheets of aluminum, the sum of the thicknesses of which is between 0.03 times and 0.32 times the thickness of the steel sheet, in order to obtain a three-layer laminate,
• rolling of the laminate to a thickness of between 0.05 mm and 0.25 mm, in order to form a foil,
• static diffusion annealing of the foil in a hydrogen atmosphere having a dew point below -30.degree. C., and
• finish rolling the foil with a total degree of reduction of greater than 20%, such that the final roughness Ra of the foil is less than 0.25 .mu.m.