Blueing is a process by which a layer of polished oxide is applied to the surface of metal parts in order to cover and protect them. The oxide of which the bluing is composed is, in general, ferric oxide and can take on a blue, brown or black color. The oxide layer acts as a coating and helps improve the appearance of the metal and prevent its corrosion.

 

 

 

 

The pieces resulting from this type of blueing take on a bluish color, which is why it is also known as bluish.

 

 

 

 

This blueing process is carried out in ovens at temperatures of 400 ° C. To start the process, it is necessary to carry out a thorough cleaning of the metal parts to loosen the rust and dirt. Subsequently, they are covered with a 25% asphalt solution.

 

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Used to reduce the effects of corrosion or as a decorative element, as it leaves the surface of the steel in a shiny black color.