Can the metal parts be black for 3-5 minutes?

 1. It can be black (HEM-902 metal room temperature blackening agent).

 

    2. Blackening is a common means of chemical surface treatment. The principle is to create a layer of oxide film on the surface of the metal to isolate the air and achieve the purpose of anti-rust. When the appearance requirement is not high, can use black processing, the surface of steel parts blackening treatment, also have been called hair blue.

 

    3. The common methods used in blackening treatment are traditional alkaline heating and black, and there are two kinds of normal temperature blackening. But the normal temperature blackening process is not very good for low carbon steel. Basic black subdivision, once again black and twice black difference. The main components of black liquor are sodium hydroxide and sodium nitrite. Black when the required temperature tolerance larger, probably between 135-135 ℃ can get a good surface, just needed some length of time.