In panel test for spalling resistance, the average face temperature of panel assembly is maintained at ______________ °C for 24 hours?

Related Mcqs:

1. With increase in the porosity, thermal spalling resistance of fireclay brick___________________?

   A. Increases
   B. Decreases
   C. Remain same
   D. May increase or decrease

2. Spalling resistance of a refractory cannot be increased by ____________________?

   A. Increasing its porosity
   B. Using a coarser grog during its manufacture
   C. Decreasing its thermal co-efficient of expansion
   D. Making it denser

3. Silica bricks have low spalling resistance below 600°C, due to its________________?

   A. Very high thermal conductivity
   B. High co-efficient of expansion upto this temperature
   C. High thermal diffusivity
   D. Low refractoriness

4. Panel test determines the _____________ of refractories?

   A. Fusion point
   B. Spalling resistance
   C. Slag penetration resistance
   D. Refractoriness under load (RUL)

5. Spalling of a refractory means its____________________?

   A. Softening
   B. Fracture due to uneven expansion at high temperature
   C. Resistance to compressive loads
   D. Resistance to chemical action of gases and molten fluxes

6. Thermal spalling mainly occurs during _____________ of furnaces?

   A. Cooling down
   B. Warming up
   C. Both A. & B.
   D. Neither A. nor B.

7. To resist spalling tendency, a refractory should have________________?

   A. Greater diffusivity
   B. Low specific heat
   C. Low thermal co-efficient of expansion
   D. All A., B. and C.

8. Spalling tendency of refractories is reduced by increasing its_________________?

   A. Porosity
   B. Specific gravity
   C. Thermal conductivity
   D. Strength

9. Cermets are combination of ceramic and metallic materials due to which they have high strength & resistance to high temperature. Cermets are used in the_______________?

   A. Hearth of the blast furnace
   B. Nuclear reactors, missiles & space crafts
   C. Insulation of high temperature furnaces
   D. Roof of electric furnaces

10. Most Cermets, which normally have high thermal conductivity and high thermal shock resistance, comprises of ceramic & metallic components of ______________ percent respectively?

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