This specification covers castings, iron-chromium-nickel-molybdenum corrosion-resistant, duplex(austenitic/ferritic) for general application. Castings shall be heat treated in accordance with the required procedure and heat-treat temperature. Proper heat treatment of these alloys is usually necessary to enhance corrosion resistance and in some cases to meet mechanical properties. Minimum heat-treat temperatures are specified; however, it is sometimes necessary to heat-treat at higher temperatures, hold for some minimum time at temperature and then rapidly cool the castings in order to enhance the corrosion resistance and meet the required mechanical properties. The steel shall conform to the required chemical composition for carbon, manganese, silicon, phosphorus, sulfur, chromium, nickel, molybdenum, copper, tungsten, and nitrogen. Castings shall be marked for material identification with the specification designation and grade.