A. Increases with rise in service temperature
B. Decreases with rise in service temperature
C. Is unaffected with change in service temperature
D. Decreases with increase in porosity
Related Mcqs:
- Cold crushing strength of ordinary fireclay brick is about 950 kg/cm2. On exposure to a temperature of about 1500°C, its crushing strength may come down to as low as ______________ kg/cm2?
A. 450
B. 250
C. 150
D. 65 - Cold crushing strength of refractories depends upon its_________________?
A. Composition
B. Texture
C. Firing temperature
D. All A., B. and C. - Cold crushing strength of fireclay bricks is about ______________ kgf/cm2?
A. 50-100
B. 100-150
C. 200-400
D. 500-1000 - Cold crushing strength of a refractory does not depend upon its ____________________?
A. Shape
B. Composition
C. Firing temperature
D. Texture - 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 - ___________________ is the measure of the strength of refractory under the combined effect of temperature & load ?
A. Porosity
B. RUL
C. Specific gravity
D. Thermal conductivity - Lessing ring is formed by the addition of a partition across the centre of a raschig ring, which results in an area increase of about ______________ percent?
A. 5
B. 20
C. 35
D. 55 - Grog addition in fireclay during brick manufacture is done to_________________?
A. Reduce its shrinkage on heating
B. Impart greater spalling resistance
C. Enhance the strength of fired refractories
D. All A., B. and C. - Silicon carbide refractories are used in the _____________?
A. Muffle furnace
B. Zinc smelting furnace
C. Ceramic recuperators
D. All A., B. and C. - Presence of MgO in alumino-silicate refractories _______________ its refractoriness?
A. Increases
B. Lowers
C. Does not affect
D. Either A. or B.; depends on its quantity
