METHOD OF MANUFACTURE OF REFRACTORY CRUCIBLE Russian patent published in 2005 - IPC

FIELD: metallurgy; manufacture of linings for induction furnaces used for melting high-quality metals and alloys.

SUBSTANCE: proposed method includes successive ramming of the crucible bottom and walls with layers of standard refractory materials and materials consisting of reactive mixture of exothermic composition. Ramming and vibration tampering of crucible layers are performed by means of one stationary and two movable templates which are placed on hearth and semi-finished item of two-layer bottom of crucible. In the course of final operation, high-temperature roasting of semi-finished item thus obtained is performed; roasting includes slow heating of crucible by preset schedule to temperature of 850-950 C continued for 4-6 hours at rate of 2.8 deg./min; then heating is intensified at rate of 10-15 deg./min till melting point is obtained, thus ensuring standard diffusion sintering and synthesizing-welding of refractories forming multi-layer structure of crucible bottom and walls. Composition of reactive mixture and quantitative ratio of its components is selected on basis of initial materials giving rise to exothermic reaction and self-propagating high-temperature synthesis. Composition of mixture depends also on kind of metal to be molten, properties and composition of ramming compound and standard refractories. Proposed method increases service life of crucible by 1.5-2 times as compared with standard methods due to high erosion and corrosion resistance to chemically active molten media of synthesized ceramic material of crucible, its low porosity and non-wettability to molten metal.

EFFECT: enhanced efficiency; increased service life of crucibles and melting furnaces.

10 cl, 3 dwg