VCBLK HB-18 Cold Blackening Chemical * Cold Blackening Chemical for Metal - Cold blackening (cold bluing) is a chemical process that darkens ferrous metals (steel, iron, stainless steel, etc.) at room temperature to provide corrosion resistance and an aesthetic black finish. Unlike hot black oxide, cold blackening does not require high temperatures and is easier to apply. * How Cold Blackening Works - A cold blackening solution typically contains selenium-based compounds or copper-selenide that react with iron to form a dark, protective coating. It does not penetrate as deeply as hot black oxide but is useful for low-friction applications and decorative finishes. # VCBLK HB-18 Cold Blackening Chemical Manufacturer.