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  • Question
  • Most Cermets, which normally have high thermal conductivity and high thermal shock resistance, comprises of ceramic & metallic components of __________ percent respectively.


  • Options
  • A. 80 and 20
  • B. 20 and 80
  • C. 50 and 50
  • D. 60 and 40

  • Correct Answer
  • 80 and 20 


  • Refractory Technology problems


    Search Results


    • 1. Refractories subjected to alternate cycles of heating & cooling are liable to loose their resistance to

    • Options
    • A. thermal spalling
    • B. slag attack
    • C. fusion under load
    • D. CO attack
    • Discuss
    • 2. Carborundum used for making crucibles for melting non-ferrous metals is chemically

    • Options
    • A. silicon carbide
    • B. silicon nitride
    • C. crystalline magnesia
    • D. zirconium sulphate
    • Discuss
    • 3. Magnesite refractories are generally not used in the

    • Options
    • A. electric furnace walls.
    • B. steel melting furnace.
    • C. open hearth furnace.
    • D. burning zone of cement kilns.
    • Discuss
    • 4. Refractories used in/for __________ should have low thermal conductivity.

    • Options
    • A. coke ovens
    • B. insulation
    • C. regenerators
    • D. muffle furnaces
    • Discuss
    • 5. Bottom of basic open hearth furnace are constructed of

    • Options
    • A. dead burnt magnesite ramming mass.
    • B. porous fireclay bricks.
    • C. semi-silica bricks.
    • D. silicon carbide bricks.
    • Discuss
    • 6. Refractory bricks with lower permeability is produced by using

    • Options
    • A. higher firing temperature.
    • B. higher moulding pressure.
    • C. finer grog size.
    • D. all (a), (b) and (c).
    • Discuss
    • 7. Which is not a natural insulating material?

    • Options
    • A. Diatomaceous earth/kieselgur
    • B. Asbestos
    • C. Vermiculite
    • D. None of these
    • Discuss
    • 8. Lower wall courses of soaking pits are made of __________ bricks to avoid the action of molten slag & scale.

    • Options
    • A. chrome or magnesite
    • B. silicon carbide
    • C. silica
    • D. lowduty fireclay
    • Discuss
    • 9. Fireclay bricks are not used in the

    • Options
    • A. blast furnace
    • B. hot blast stove
    • C. cupola
    • D. wall of coke oven
    • Discuss
    • 10. Addition of grog in fireclay brick during its manufacture is advantageous, because it results in

    • Options
    • A. less shrinkage in heating, decreased apparent porosity & increased specific gravity.
    • B. high strength & thermal spalling resistance.
    • C. less addition of water to get a workable plasticity & lesser time required for drying the raw refractories and hence increased rate of production.
    • D. all (a), (b) and (c).
    • Discuss


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