• Our Silicon Carbide Crucibles

    A Shape Crucibles (Small)

  • Our Silicon Carbide Crucibles

    A Shape Crucibles (Big)

  • Our Silicon Carbide Crucibles

    TP - Shape Crucibles (Without Spout)

  • Our Silicon Carbide Crucibles

    TP - Shape Crucibles (Spouted)

  • Our Silicon Carbide Crucibles

    TP - Shape Crucibles (Spouted Basin)

  • Our Silicon Carbide Crucibles

    Basin - Shape Crucibles

PRODUCTS

Procedure For Crucible Handling

Inspection of Crucible

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.

Storage

  1. Store Crucibles in a warm and dry place.
  2. Store them on wooden pallets freely.

Inspection of Furnace

  1. Check the condition of inside refractory lining of furnace. In case of any damage or wear & tear, it must be repaired at the earliest possible opportunity. Uneven refractory lining in damaged form will deflect the flame and proper distribution of heat will not be there, resulting in more heating time and fuel consumption. Proper energy consumption records should be maintained to monitor the condition of furnace.
  2. Loose debris should be removed from the side and bottom of the furnace. Ensure that no carbon deposition takes place in front of burner outlet.
  3. Drain hole and its flap should be checked time to time. It is advisable to have flap made of Zinc Plate to ensure that metal will automatically come out of furnace in case of metal leakage.
  4. Thermocouples should be calibrated periodically.
  5. Check the flame condition and its length by test firing it outside ( if possible ) Burner nozzles to be cleaned with compress air preferably since use of hard wires might increase the nozzle aperture.
  6. Quality of coke and Iron grates should be checked for coal fired furnace.
  7. Condition of metallic elements or Silicon Carbide elements should be checked for their oxidation.
  8. Check the dimension of furnace so that proper gap is maintained between crucible and lining.

Installation of Crucible

It is very difficult to discuss all aspects of cares to be taken in installation o crucible since requirement changes with the change of furnace and change crucible shape. What is applicable in one case may not be necessary in other case. Therefore, it is utmost necessary to understand the purpose. Followings few cares should be taken wherever necessary:

  1. Stand
  2. Stand should be used of preferably 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.

    Though, there is no uniformity of mind all over the world for the height of stand. It is recommended to have such height so that the top of stand and centre line of flame coincide with each other.

    Install the stand firmly at the centre of furnace. The stand must have a 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 griping.

  3. Grip Bricks and Expansion Gaps
  4. Required grip bricks should be placed leaving expansion gaps of about 3mm. In case of less or no gap, crucible will develop crack. For this you should use three mm paper sheet while installation so that required gap will be created after burning of paper during usage.

  5. Pre-heating
  6. All crucibles must be pre-heated to red hot before charging. The most common cause for early failure of crucible is thermal shock. Carbon bonded SIC Crucibles can absorb more thermal shocks than Clay-Graphite Crucibles. Hence, pre-heating schedule should be worked out suitably depending upon the following factors

    • Quality of crucible used is Clay Graphite or Carbon Bonded / Resin Bonded SIC crucible.
    • Size of crucible & metal / alloy to be melted.
    • Type of heating system.

    Care should be taken that crucible is free from moisture before inserting in the furnace. Flame should be tangential in oil fired furnaces and it should be located midway between crucible and refractory lining.

Preheating

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.

  1. Whether Clay-Graphite Crucible or Silicon Carbide Crucible?
  2. Whether new Crucible or Old Crucible?
  3. Whether new Furnace or Old Furnace?
  4. Size of Crucible?
  5. Type of heating system, etc.?

All Right Reserved © 2013

Design By : Sanah Group