CASTING OF METAL

摘要

METHOD FOR CONTINUOUSLY CASTING METAL STRIP OF THE KIND IN WHICH MOLTEN METAL IS INTRODUCED INTO THE NIP BETWEEN A PAIR OF PARALLEL CASTING ROLLS (16) VIA A METAL DELIVERY NOZZLE (19) DISPOSED ABOVE THE NIP TO CREATE A CASTING POOL (30) OF MOLTEN METAL SUPPORTED ON CASTING SURFACES (16A) OF THE ROLLS IMMEDIATELY ABOVE THE NIP AND THE CASTING ROLLS (16) ARE ROTATED TO DELIVER A SOLIDIFIED METAL STRIP (20) DOWNWARDLY FROM THE NIP.THE CASTING SURFACES (16A) ARE SMOOTH SO AS TO HAVE AN ARITHMETIC MEAN ROUGHNESS VALUE (RA) OF LESS THAN 5 MICRONS AND THE CASTING POOL CONTAINS MATERIAL TO FORM ON EACH OF THE CASTING SURFACES A THIN LAYER INTERPOSED BETWEEN THE CASTING SURFACE AND THE CASTING POOL DURING METAL SOLIDIFICATION A MAJOR PROPORTION OF WHICH LAYER IS LIQUID DURING THE METAL SOLIDIFICATION AND THE LIQUID OF THE LAYER HAS A WETTING ANGLE OF LESS THAN 40° ON THE CASTING SURFACE. THIS PROMOTES WETTING OF THE SMOOTH CASTING SURFACES AND INCREASES HEAT FLUX DURING METAL SOLIDIFICATION.