Blackening of steel is a surface treatment of the material, which simultaneously gives the color appearance of the material and protects and preserves it at once. It is particularly suitable for oxidizable steels. It is a classic method of surface treatment by oxidation.
Precise degreasing is a prerequisite for creating a quality and flawless black coating. In case of corrosion or scales on the treated parts, these defects should be removed by sandblasting.
Blackening is performed by immersing the steel in a special boiling bath at a temperature of about 140 ° C.
The result is the formation of a conversion oxide layer on the surface of blackened parts with a thickness of about 1μm. At the same time, thanks to suitable preservatives it increases the corrosion resistance of the steel.
The advantage of this surface treatment is a nice decorative appearance of the material, greater resistance to corrosion, long life, good abrasion resistance. Another advantage of alkaline blackening is the low thickness of the oxide layer, which does not change the dimensions of the surface-treated components.