Inspect the Crucible carefully immediately after receipt as well as before taking into use. Care should be taken that glaze / protective coat do not get damaged, otherwise life will be affected.
Store Crucibles in a warm and dry place. »Store them on wooden pallets freely.
It is very difficult to discuss all aspects of cares to be taken in installation of Crucibles since requirement changes with the change of furnace and change of Crucible shape. What is applicable in one case, may not be necessary in other case. Therefore, it is utmost necessary to understand the purpose. Few cares described hereunder should be taken wherever necessary :
Stand should be used preferably of same material as that of Crucible to ensure uniform heating of the bottom of the Crucible and to minimize undesired thermal strains. Stand should confirm in diameter to the corresponding size of Crucible base in order to provide adequate support. It is recommended to have height of the stand so that the top of stand and the centre line of flame coincide with each other.
Install the stand firmly at the centre of the furnace.
The stand must have flat surface and it must be ensured that no foreign solid fragments fall between the Crucible and Stand.
In oil fired Bale-out furnace, since it is desired to rotate the Crucible every week, some non sticky material like asbestos sheet or coke powder should be placed. Similarly it should be put in lift-out furnace for easy removal. Whereas it should be fixed firmly with high conducting patching Cement in case of tilting furnace for better gripping.
Place the Crucible carefully on the stand without hitting with furnace lining, etc. Locate it centrally.
Required grip bricks should be placed leaving expansion gaps of about 3 mm. In case of less or no gap, Crucible will develop crack.
Crucible should be preheated to red hot condition before charging. Most common cause for early failure is thermal shock. Carbon-Bonded SiC Crucibles can absorb more thermal shock than Clay - Graphite Crucibles. Hence, preheating schedule should be designed suitably depending upon the following factors.