PURPOSE: To provide a crucible wherein damaging such as crack is not generated by forming an innermost lining layer to be in contact with molten metal from a dry ramming material to which sintered binder is added and providing on the outside thereof a lining layer comprising dry ramming material to which sintered binder is not added.
CONSTITUTION: A crucible type induction furnace 1 has a plurality of refractory lining layers 3-6 and an induction coil 2 is disposed on the outside thereof. And a lining layer 6, the innermost layer, in contact with molten metal M is formed from refractory material which is prepared by adding 1-5wt.% of sintered binder such as boric acid, phosphoric acid to dry ramming material such as alumina, magnesia. And a lining layer 5 disposed on the outside of the layer 6 is formed from dry ramming material to which sintered binder is not added so that even if it is heated, when in use, the dry ramming material remains as it is in the form of dry powders. Consequently, even if cracks are generated in the layer 6, leakage of molten metal is prevented by the layer 5, thereby surely preventing occurrence of leakage of molten metal.
WAKASAKI OSAMU
TOYOSHIMA MASAYASU
OSONO TOMOYA
WASHIO JISHICHI
TOSHIBA CERAMICS CO
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