Method of casting metal ingots

Claim 1

PROCESS OF CASTING HIGH MELTING WORKABLE METALS TO FORM A BODY THEREOF HAVING A SURFACE SUITABLE FOR WORKING BY FORGING, ROLLING, DRAWING, OR THE LIKE WITHOUT SURFACE TREATMENT OF SAID BODY FOR REMOVAL OF SURFACE IMPERFECTIONS WHICH DELETERIOUSLY AFFECT THE WORKED ARTICLES FORMED FROM SAID METALS, WHICH PROCESS COMPRISES PREPARING A BATH OF MOLTEN METALLIC SILICATE MATERIAL INERT TO SAID METAL TO BE CAST, SAID SILICATE MATERIAL BEING FURTHER CHARACTERIZED IN THAT ITS MELTING POINT IS BELOW THAT OF SAID METAL; INTIMATELY CONTACTING THE INNER WALLS OF A CASTING FORM WITH SAID MOLTEN BATH OF SILICATE MATERIAL; CHILLING SAID MOLTEN SILICATE MATERIAL IN CONTACT WITH SAID INNER WALLS OF SAID CASTING FORM TO FORM A SHELL REINFORCED BY SAID CASTING FORM; MAINTAINING THE INNER WALLS OF SAID SHELL AT A TEMPERATURE IN EXCESS OF THE OUTER WALLS THEREOF; AND POURING INTO SAID SHELL A REFINED AND PURIFIED MOLTEN MASS OF SAID WORKABLE METAL AT A TEMPERATURE ABOVE THE MELTING POINT OF SAID SHELL AND AT A RATE SUCH THAT A PORTION OF THE INNER WALLS OF SAID SHELL ARE MELTED AND A SURFACE SKIN OF FROZEN METAL FORMS WITHIN THE REMAINING PORTIONS OF SAID SHELL WITHOUT CONTACT WITH THE INNER WALLS OF SAID CASTING FORM.