Blacking at room temperature means the dipping of iron components in a mild, light chemically, non-polluting solution at about 20°C. The effect of the solution is a change of the surface structure. Treated surfaces will get a black coat of iron oxide.Room temperature blacking process is a simple dip operation specifically designed for use in factories. The process does not materially effect dimensions and a uniform colouring is obtained over machined surfaces, threads and blind holes. Blacking is achieved by chemical conversion of the metal surface and the process entails degreasing, immersion in a surface conditioner, and blacking solution. Corrosion protection is afforded by a final immersion in a dewatering oil.