THE CONVENTIONAL ROUTE FOR THE PRODUCTION OF ALUMINIUM ROLLED PRODUCTS INVOLVES DC (DIRECT CHILLED) CASTING OF BLOCKS OF 300 - 650 MM THICKNESS. THESE ARE COOLED AND THEN HEATED UP AGAIN FOR HOT ROLLING (GOING THROUGH HOT ROLLS WHILE HOT), TO 2 - 5 MM FOR COILING AND SUBSEQUENT COLD ROLLING. TO AVOID HEAT LOSSES DUE TO COOLING AND HEATING AND POWER LOSSES DUE TO HOT ROLLING, A METHOD HAS BEEN DEVELOPED FOR DIRECTLY CASTING LIQUID ALUMINIUM INTO THIN STRIPS. THIS CAN BE DONE IN DIFFERENT TYPES OF STRIP CASTING : HORIZONTAL DC STRIP CASTING, PELLET-ROLLING (COMPACTING AND ROLLING PELLETS INTO STRIPS) AND SPRAY ROLLING (COMPACTING AND ROLLING A SPRAY INTO STRIPS).

A TOTAL ENERGY AUDIT OF SIX TYPICAL ROLLED PRODUCTS PRODUCED BY BOTH ROUTES WAS UNDERTAKEN TO DETERMINE THE POTENTIAL ENERGY SAVINGS. IT WAS CONFIRMED THAT ENERGY SAVINGS UP TO 37 % WERE POSSIBLE USING THIN STRIP CASTING METHODS. THESE SAVINGS WERE LESS THAN EXPECTED BECAUSE OF INCREASED COLD MILL PASSES AND LONG HIGH TEMPERATURE HOMOGENISING ANNEALING REQUIREMENTS. THESE PARTIALLY OFFSET THE ENERGY GAINS OF ELIMINATING THE SCALPING, PREHEATING AND HOT ROLLING OPERATIONS OF THE CONVENTIONAL ROUTE.

THE ENERGY REQUIREMENTS OF BOTH PROCESSING ROUTES FOR ALL SIX PRODUCTS SELECTED WERE RELATED TO A TYPICAL PRODUCT MIX OF 40,000 TONNES PER ANNUM. IT WAS ESTABLISHED THAT THE POTENTIAL ENERGY SAVING USING THE THIN STRIP CASTING ROUTE TO ACHIEVE THIS OUTPUT WOULD BE APPROXIMATELY 25 % OR 3 MILLION THERMS, EQUIVALENT TO 315,517 GJ PER ANNUM.

THE ANNUAL ENERGY SAVINGS FOR ROLL CAST PRODUCTS AT THIS FACTORY LEVEL OF OUTPUT AMOUNTED TO 246,000 GJ. THIS ENERGY SAVING FOR THE SAME PRODUCT MIX IS EQUIVALENT TO A TOTAL SAVING OF 1,057,000 GJ IN THE UK AND 9,738,000 GJ IN THE EEC FOR THE 1982 PRODUCTION TONNAGES OF THESE AREAS.

A FURTHER INCENTIVE FOR USING THE ROLL CAST PROCESS, WHEN ESTABLISHING A NEW PRODUCTION SOURCE OR EXTENDING THE CAPACITY OF AN EXISTING CONVENTIONAL ROUTE, IS THE SAVING IN CAPITAL PLANT EXPENDITURE. THE CURRENT SAVING WAS CALCULATED TO BE 45 M UKL FOR AN ADDITIONAL 36,000 TONNES PER ANNUM OF THE SELECTEC PRODUCT MIX.