Corrosion-resistant ferritic chrome-molybdenum-nickel steel

Claim 1

A ferritic chrome-molybdenum-nickel steel of high chemical resistance against general and intercrystalline corrosion attack as well as against pitting, crevice and stress corrosion in chloride-containing solutions consisting essentially of: ______________________________________ 18 to 32 % chromium 0.1 to 6 % molybdenum 0.5 to 5 % nickel 0.01 to 0.05 % carbon 0.02 to 0.08 % nitrogen 0.10 to 0.60 % niobium 0.005 to 0.50 % zirconium 0.01 to 0.25 % aluminum up to 0.25 % titanium up to 3 % copper up to 3 % silicon up to 1 % manganese up to 0.01 % each calcium, magnesium, cerium or cerium mixed metal, boron remainder iron and impurities due to the melting process. ______________________________________ wherein the niobium content is at least 12-times that of the carbon and at most 12-times + 0.20%, and the total content of zirconium plus 3.5-times the aluminum content at least 10-times that of the free, non-niobium-bound nitrogen content and at most 10-times + 10% according to the formula: ##EQU2##