Blued Steel

Bluing (steel)

Bluing, sometimes spelled as blueing, is a passivation process in which steel is partially protected against rust using a black oxide coating. It is named after the blue-black appearance of the resulting protective finish. Bluing involves an electrochemical conversion coating resulting from an oxidizing chemical reaction with iron on the surface selectively forming magnetite, the black oxide of iron. In comparison, rust, the red oxide of iron, undergoes an extremely large volume change upon hydration; as a result, the oxide easily flakes off, causing the typical reddish rusting away of iron. Black oxide provides minimal protection against corrosion, unless also treated with a water-displacing oil to reduce wetting and galvanic action. In colloquial use, thin coatings of black oxide are often termed "gun bluing", while heavier coatings are termed "black oxide". Both refer to the same chemical process for providing true gun bluing.

Steel

Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to its high elastic modulus, yield strength, fracture strength and low raw material cost, steel is one of the most commonly manufactured materials in the world. Steel is used in structures, in bridges, infrastructure, tools, ships, trains, cars, bicycles, machines, electrical appliances, furniture, and weapons.

Steel blue

Steel blue is a shade of blue color that resembles blue steel, i.e., steel which has been subjected to bluing for protection from rust. It is one of the less vibrant shades of blue, and is usually identified as a blue-gray color. An archaic term for it is chalybeous.

blued

Verb

1. simple past and past participle of blue

Adjective

1. Having the property of having been chemically passivated.

steel

Noun

1. An artificial metal produced from iron, harder and more elastic than elemental iron; used figuratively as a symbol of hardness.
2. Any item made of this metal, particularly including.

Adjective

1. Made of steel.
2. Similar to steel in color, strength, or the like; steely.