Blued steels are cold rolled steels that have been oxidised by annealing in a special installation to produce a very thin magnetite layer (Fe₃0₄) on the surface (less than 1 µm thick).

Blued steels provide protection against corrosion for parts whose surface cannot be protected by normal painting or any metallic coating processes. The magnetite layer can withstand moderate bending and drawing operations. The sheet surface is very clean and retains its attractive appearance during storage.

The main areas of use are:

• Stove pipes
• Food contact other than packaging
• Cake and biscuit moulds
• Baking trays
• Lining of industrial bread ovens

Blued steels are suitable for food contact, under certain conditions laid down in European Regulation (EC) No. 1935/2004 and French standard NF A 36-714. Please contact us for further information on this subject.

The processing conditions for blued steels are similar to those for cold forming. However, in the case of difficult drawing operations, the oxide layer may crack and lose its continuity.

Corrosion resistance is better than for uncoated cold rolled steels, but is nevertheless limited, particularly in humid atmospheres.

Blued steels can be supplied with or without oil film.