Resistance to fusion of the refractory under a steady rising temperature condition is called

Dry mix hydraulic compositions of refractory aggregates with suitable bonding materials are called refractory

A

Mortars

B

Cements

C

Castables

D

None of these

If a refractory contains high content of silicon, it means refractory is

A

Acidic

B

Basic

C

Neutral

D

Brittle

An insulating refractory brick should have high porosity and low thermal conductivity. Which of the following is not used for inducing porosity in the insulating refractory bricks during its manufacture?

A

Cork

B

Saw dust

C

Sand

D

Chemically prepared foam

If the thermal conductivity of a wall material is independent of temperature, the steady state temperature distribution in the very large thin plane wall having steady, uniform surface temperature follows __________ law.

A

Hyperbolic

B

Parabolic

C

Linear

D

Logarithmic

Fusion point of an acidic refractory material is

A

Increased by the addition of basic oxides

B

Reduced by the addition of basic oxides

C

Not affected by the addition of basic oxides

D

Not affected by the addition of basic oxides

Fusion point of a basic refractory material is

A

Reduced by the addition of acid oxides

B

Increased by the addition of acid oxides

C

Not affected by the addition of acid oxides

D

Always less than 1000°C

If the thermal conductivity of a wall material is independent of temperature, the steady state temperature distribution in the very large thin plane wall having steady, uniform surface tempeature follows __________ law.

A

Parabolic

B

Hyperbolic

C

Linear

D

Logarithmic

Capacity of a refractory brick to withstand-sudden changes in temperature is denoted by the property called

A

Spalling resistance

B

Refractoriness

C

Refractoriness under load (RUL)

D

None of these

Resistance to slag attack of a refractory

A

Depends on the nature of slag & refractory

B

Decreases at higher temperature

C

Decreases, if defective joints & cracks exist in the refractory

D

All of the above

Spalling resistance of a refractory can not 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

Resistance to fusion of the refractory under a steady rising temperature condition is called

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