This International Standard specifies requirements for black oxide coatings on iron and steel (including cast and wrought iron, carbon steel, low alloyed steel and stainless steel). Black oxide coatings can be used to diminish friction between sliding or bearing surfaces or for decorative purposes or to reduce light reflection. Such coatings, with or without supplementary preservative treatment, may be used where a black surface is required. Only very limited corrosion protection is obtained under mildly corrosive conditions even with preservative treatment. This International Standard does not specify requirements for the condition, finish or surface roughness of the substrate prior to black oxidizing.