Sidewall containment of liquid metal with vertical alternating magnetic fields

In a system for continuous roller casting of a solid sheet of metal including a pair of rollers adjacent to one another and separated by a gap, said pair of rollers adapted to receive a pool of molten metal and to force molten metal between said pair of rollers by counter rotation of said pair of rollers to cast said molten metal into a solid sheet, the improvement comprising:

• magnet means including a pair of magnets located adjacent to opposite ends of a pair of rollers and capable of generating an alternating vertical magnetic field thereby generating eddy currents in the skin of said molten metal, said eddy currents being the only electric currents generated in said molten metal and said eddy currents interacting with said alternating vertical magnetic field to produce a horizontal force in the skin of said molten metal, said force pressing said molten metal in a direction away from said alternating vertical magnetic field thereby preventing flow of said molten metal beyond said ends of said rollers, wherein the field generated by said magnet means satisfies the equation:
• B=(2u.sub.o g.rho.h).sup.1/2
• where U.sub.o is the permeability of free space, g is the acceleration of gravity, .rho. is the density of the metal, and h is the downward distance from the surface of said pool of molten metal.