METAL BLACKENING PRICESS. - Metal blackening is a process used to create a black oxide coating on the surface of ferrous metals, such as steel and iron. This coating enhances corrosion resistance, reduces light reflection, and improves the appearance of the metal. The blackening process can be performed using various methods, including hot and cold blackening. - Methods of Metal Blackening 1. Hot Blackening 1. Process: Hot blackening involves immersing the metal in a series of tanks containing different chemicals, including caustic soda, nitrates, and nitrites, at high temperatures (usually around 285°F to 310°F or 140°C to 155°C). 2. Steps: . Cleaning: The metal is thoroughly cleaned to remove any oils, dirt, or rust. This can involve degreasing and acid pickling. . Rinse: The metal is rinsed to remove any cleaning residues. . Blackening: The metal is submerged in the hot blackening solution, where a chemical reaction occurs, forming a black iron oxide layer. . Rinse: Another rinse to remove any remaining chemicals. . Sealing: The metal is often sealed with oil or wax to enhance corrosion resistance and improve the finish. - Applications: Commonly used for firearms, tools, and industrial components.