Abstract: An induction heating coil assembly for use in a roller induction heating line has a magnetic shunt for receiving a portion of an electromagnetic field generated along the axis of the induction coil and directing that portion along a path parallel to a workpiece passing along the heating line. This flux path ensures that eddy currents induced in the workpiece flow primarily perpendicular to the axis of the workpiece, and not along the axis of the workpiece where they could cause arcing between the moving workpiece and the conveyor rolls.

Abstract: An induction heating furnace is disclosed comprising an induction coil assembly and a ladle having a metallic shell that supports a crucible holding metal to be heated by the furnace. The ladle is readily separated from the induction coil assembly so that the heated metal may be conveniently and reliably moved among operational stations. The induction coil assembly has a preselected length which is less than the length of the shell. The induction coil assembly surrounds, but does not touch the shell and generates an electromagnetic induction field. The induction coil assembly comprises a coil, upper and lower yokes and an intermediate yoke coextensive with the coil. The upper and lower yokes are separated from each other and electromagnetically coupled together by the intermediate yoke. The upper, lower and intermediate yokes each comprise stacked laminates formed of sheets of ferrous material.

Abstract: An induction furnace is disclosed comprising a crucible for holding a material to be heated by the furnace, an induction coil assembly, and a module-support assembly surrounding and radially supporting the induction coil assembly so as to facilitate the replacement and reconnection of the induction coil assembly. The induction coil assembly comprises an induction coil, an upper yoke, a lower yoke, and a plurality of intermediate yokes that are spaced apart from each other. The induction coil is wound around the crucible and defines the periphery of the induction furnace. The intermediate yokes are arranged to extend around substantially all of the periphery defined by the wound induction coil. The upper and lower yokes are electromagnetically coupled together by the plurality of intermediate yokes.

Abstract: Induction heating vessels and methods are disclosed. One embodiment of an induction heating vessel is a bottom pouring vessel with a crucible for containing a molten metal to be heated and having an outlet in the bottom. A metallic shell with integral current limiters surrounds the crucible. A stopper is provided for selectably controlling the flow of molten metal through the outlet. A method of preheating an induction heating vessel comprises placing a susceptor inside the vessel prior to charging the vessel with material to be heated and inductively heating the susceptor by an induction coil.

Abstract: An induction melting vessel comprising a refractory crucible having an opened top end and closed bottom end, with a substantially continuous side wall. A substantially continuous metallic shell surrounds and generally conforms to the side wall and extends for at least a majority of the height of the side wall from the bottom end to the top end. The shell has a bottom end corresponding to the bottom end of the crucible and a top end corresponding to the top end of the crucible. A portion the shell adjacent the top end thereof and a portion of the shell adjacent the bottom end thereof have discrete physically integral but electrically isolated regions therein for limiting the flow of electric current in the shell. In one embodiment of the invention, the regions are defined by a plurality of slits through the shell and extending from the top and bottom ends thereof toward the respective opposite ends. The slits have a length not exceeding have the distance to the respective opposite end.

Abstract: A method of refining steel utilizing induction melting furnaces sized for use in micro mills consists of charging a medium frequency induction melting furnace having a maximum production rate of about 50 tons per hour with pre-refined steel, and melting steel in the furnace. The melted steel is transferred to a refining vessel, the refining vessel has a high free board, induction heating and stirring capacity and apparatus for supplying blasts of gas. The refined steel is then transferred to a tundish for a continuous casting operation.