Blackodising process for steel. The process is a cost effective alternative to the traditional hot blacking process. It produces a black finish which, when oiled, gives a pleasing luster. More than 200 hours before white rust Enhanced black appearance Chemical Blacking is sometimes referred to as ‘Blackening’ or ‘Blackodising’ and is a conversion coating meaning that where in other metal finishing processes a layer is added above the substrate, here a coating is achieved through a chemical reaction between the ferrous metal and the oxidizing salts used in the black.