Ferritic stainless steel strip or sheet, in particular for exhaust systems

Process for the production of ferritic stainless steel strip or sheet consisting essentially of, in % by weight:

• (C+N)<0.060;
• Si<0.9;
• Mn<1;
• Cr=15 to 19;
• Mo<1;
• Ni<0.5;
• Ti<0.1;
• Cu<0.4;
• S<0.02;
• P<0.045;
• Zr=0.10 to 0.50, and 7(C+N)-0.1.ltoreq.Zr.ltoreq.7(C+N)+0.2;
• Nb=0.25 to 0.55, when Zr.gtoreq.7(C+N);
• Nb=0.25+7(C+N)-Zr to 0.55+7(C+N)-Zr when Zr<7(C+N);
• Al=0.020 to 0.080;
• and
• Fe, balance,
• wherein the Al is in solid solution except for an amount which is no greater than 0.003%, comprising the steps of:
• hot rolling to a thickness between 2.5 and 5 mm;
• annealing the hot rolled strip or sheet at 800.degree. to 1000.degree. C. under substantially non-oxidizing conditions;
• shot blasting to clean the annealed strip or sheet;
• cold rolling the shot blasted strip or sheet to a delivery thickness between 0.6 and 3 mm;
• final annealing the cold rolled strip or sheet at between 980.degree. and 1020.degree. C.;
• and
• subjecting the final annealed strip or sheet to a cold working pass or "skin" pass producing a degree of elongation of less than 1%.