A steel material having a good resistance to corrosion, consisting of an alloy containing in % by weight: max 0.12 C 0.5-1.5 N 12-18 Cr max 0.5 Mn max 0.5 Ni 1-5 (Mo+W/2) max 1.5 (V+Nb/2+Ti) 0.1-0.5 Si from traces and up to max 2.0 Co from traces and up to max 0.1 S balance iron and essentially only impurities at normal contents.