Process for producing malleable iron castings

Claim 1

THE PROCESS OF MAKING MALLEABLE IRON CASTINGS WHICH CONSISTS IN FORMING A MOLTEN MALLEABLEIZABLE WHITE IRON MIX, ADDING TO SAID MOLTEN MIX JUST BEFORE POURING A PREDETERMINED SMALL PERCENTAGE OF ABOUT 0.003-0.03% OF ALUMINUM IN SUCH AMOUNT AS TO EFFECT A MARKED REDUCTION IN THE SIZE AND INCREASE IN THE NUMBER OF THE NODULES OF GRAPHITIZED CARBON PRODUCED IN THE CASTING AFTER MALLEABLIZING BUT INSUFFICIENT IN AMOUNT TO PRODUCE PRIMARY GRAPHITIZATION OF THE COMBINED CARBON IN THE CASTING AS POURED, POURING THE CASTING, COOLING AND REMOVING THE CASTING FROM THE MOLD AS A WHITE IRON CASTING SUBSTANTIALLY FREE OF GRAPHITIZATION, SUBJECTING THE CASTING TO A PRELIMINARY HEATING WITHIN THE TEMPERATURE RANGE OF ABOUT 400* TO 800* F. FOR A LIMITED PERIOD OF TIME TO DEVELOP SAID MARKED REDUCTION IN THE SIZE OF THE NODULES OF GRAPHITIZED CARBON PRODUCED IN THE MALLEABLE IRON CASTING, AND THEREAFTER MALLEABLIZING THE CASTING BY SUBJECTING SAID CASTING TO A MALLEABLIZING HEAT TREATMENT, THE TIME DURING WHICH THE CASTING IS SUBJECTED TO SAID MALLEABLIZING TREATMENT TOGETHER WITH THE TIME OF SAID PRELIMINARY HEATING BEING SUBSTANTIALLY LESS THAN THE HEATING TIME REQUIRED TO PRODUCE A MALLEABLIZED CASTING FROM THE SAME MIX IN THE ABSENCE OF SAID ALUMINUM ADDITION UNDER OTHERWISE COMPARABLE CONDITIONS.