Method for continuous casting of metal

Claim 1

IN A METHOD FOR CONTINUOUSLY CASTING COPPER BASE METAL IN WHICH MOLTEN COPPER BASE METAL IS FED INTO THE TOP OF A VERTICALLY DISPOSED OPEN-ENDED MOLD HAVING A CHILL SECTION FOR CASTING THE MOLTEN METAL AND CAST METAL IS WITHDRAWN FROM THE OTHER END OF THE MOLD WHILE MAINTAINING THE LEVEL OF THE METAL IN THE MOLD BELOW THE TOP OF THE CHILL SECTION, SAID CHILL SECTION PRESENTING A GRAPHITE FACE TO THE METAL CAST THEREIN, AND THE MENISCUS OF THE METAL IN SAID CHILL SECTION IS VERTICALLY RECIPROCATED WITH RESPECT TO THE WALL OF THE CHILL SECTION, THE IMPROVEMENT IN COMBINATION THEREWITH WHICH COMPRISES FEEDING SAID MOLTEN METAL TO SAID CHILL SECTION AT A TEMPERATURE WHICH IS LESS THAN ABOUT 200*F. ABOVE THE FREEZING POINT OF THE METAL BEING CAST, INTRODUCING A GAS CONTAINING MORE THAN ABOUT 40% BY VOLUME OF HYDROGEN TO THE MENISCUS OF THE METAL IN THE CHILL SECTION DURING THE CASTING PROCEDURE, AND CONTROLLING THE AMOUNT OF HYDROGEN WHICH IS DELIVERED TO SAID MENISCUS BY CONTROLLING THE AMOUNT OF SAID HYDROGEN DELIVERED TO THE MENISCUS DURING THE CASTING PROCEDURE TO A RATE OF INTRODUCTION WHICH IS BETWEEN THAT RATE WHICH PRODUCES AN IRREGULAR PATTERN OF IRREGULARITIES ON A MAJOR PORTION OF THE SURFACE OF THE CASTING EMERGING FROM THE MOLD AND THAT RATE WHICH PRODUCES DEEP TEARS ON THE SURFACE OF THE EMERGING CASTING.