METHOD FOR REPAIRING, METHOD FOR ELECTROSLAG FUSION, APPARATUS FOR ELECTROSLAG FUSION AND CRYSTALLIZER OF APPARATUS FOR ELECTROSLAG FUSION OF CAST-IRON ROLLING ROLLS Russian patent published in 1999 - IPC

FIELD: ferrous metallurgy, special electrometallurgy, possibly repairing and restoration of cast-iron rolling rolls. SUBSTANCE: method for repairing cast-iron rolling rolls comprises steps of turning roll barrel until diameter consisting 0.9-0.95 of nominal diameter; before fusion heating roll in vertical furnace up to 600-650 C at rate no more than 50 C/hour; realizing barrel fusion until size consisting 1.01-1.015 of nominal diameter of roll barrel by means of electroslag fusion in movable crystallizer at pouring liquid slag into crystallizer; melting non-compact material in slag bath and moving crystallizer relative to vertically arranged roll; after fusion subjecting roll to heat treatment in furnace preliminarily heated to 600-650 C; then cooling roll in furnace until temperature 100-150 C at rate no more than 50 C/hour. Method for electroslag fusion of cast-iron rolling rolls is performed in crystallizer having at least two mutually insulated sections arranged one over another. Lower section is forming one, upper section has electric current supply lead. Slag bath overlies said sections. Lower level of slag bath is spaced by distance equal to (0.5-1.0)t mm from lower edge of electric current supply section, where t mm - thickness of fused layer. Apparatus for electroslag fusion of cast-iron rolling rolls includes carrying column, carriage for moving crystallizer, carriage for moving upper centering device, car-trough on which in centering device with electric current supply trough roll is vertically mounted in such a way that end of its barrel rests upon support. Telescopic screen protects lower necking portion of roll and fused portion of barrel from environment. Crystallizer of apparatus for electroslag fusion of cast-iron rolling rolls includes three water cooled and mutually insulated sections. Upper section has electric current supply lead and one continuous vertical groove, it is protected by means of solid graphite ring. Height of intermediate section is no more than thickness of fused layer and it is stepwise reduced by 10-20 degrees under end portion of graphite ring. First forming section is provided with pickup for detecting level of melt metal. Distance from lower edge of forming section until pickup is equal to (0.5-1.0) of thickness value of fused layer. EFFECT: restoration of roll working capacity, enhanced quality of fused metal due to stabilized electroslag fusion process. 14 cl, 4 dwg