METHOD FOR MAKING HOLLOW INGOTS BY ELECTROSLAG SURFACING Russian patent published in 2002 - IPC

FIELD: surfacing processes and equipment, possibly electroslag surfacing for making, mainly hollow cylindrical parts such as bandages for bimetallic rolling rolls. SUBSTANCE: method comprises steps of preparing slag bath by non-consumable electrode in melting space restricted by means of crystallizer and surfaced face of part; supplying pelletized additive material by means of controlled metering device; additionally supplying melt additive metal out of intermediate unit; using inner and outer crystallizers and non-consumable graphite diametrically arranged electrodes; setting width of electrodes in radial direction of surfaced part according to expression : Lel = inner R out.cr.- outer R in.cr. - 2B, where inner R out.cr. - inner radius of outer crystallizer, mm; outer R in.cr. - outer radius of inner crystallizer,mm; B = (8 - 20) mm - distance between lateral surface of electrode and inner surfaces of inner and outer crystallizers. Pelletized additive material is supplied by means of diametrically arranged metering devices at supply width in radial direction determined according to expression: C met = inner R out.cr. - outer R in.cr. - a - d, where a,d - spacing between supply zone and walls of inner and outer crystallizer respectively; a = (40-80) mm; d = (4-10) mm. Volumetric relation of pelletized additive material to additive metal in central zone of surfaced part consists (0.2 -0.28) and on edges along (9-11)% of length of lower and outer ends of surfaced part it consists (0.1-0.12)%. Method provides concentration of pelletized additive material on worn surface of part up to (50-60)%. EFFECT: enhanced quality of surfaced layer due to combination supply of pelletized additive material and melt additive metal. 1 dwg, 1 tbl