TasDia Network
TasDia Network

MCQs 1: Carbon refractories_____________________?

Do not burn/oxidise, when exposed to air on heating Are not attacked by slags, as they are not wetted by melts Do not resist temperature fluctuations Have extremely low thermal & electrical conductivities
Answer Explanation

MCQs 2: Refractoriness under load (RUL) of fireclay bricks (under a load of 2 kg/cm2) is ______________ °C?

500 1000 >1350 >2000
Answer Explanation

MCQs 3: Natural silica___________________?

Mainly contains quartz Is not stable at high temperature Transforms to other allotropic forms i.e. Tridymite and Cristobalite involving very high volume changes All A., B. and C.
Answer Explanation

MCQs 4: Spalling tendency of refractories is reduced by increasing its_________________?

Porosity Specific gravity Thermal conductivity Strength
Answer Explanation

MCQs 5: Which is not a high alumina refractory ?

Mullite Corundum Bauxite Dolomite
Answer Explanation

MCQs 6: Which brick undergoes maximum shrinkage on drying ?

Tar bonded dolomite bricks Fireclay bricks Magnesite bricks Chromite bricks
Answer Explanation

MCQs 7: 10 to 30% magnesite is added to Chromite to produce chrome-magnesite refractories. Magnesite addition is mainly done to improve the _____________ of Chromite?

Spalling resistance Refractoriness Crushing strength Resistance to slag
Answer Explanation

MCQs 8: Furnace atmosphere for softening temperature determination of refractories (in which Seger Cones are placed) should be __________________?

Oxidising Neutral Either A. or B. Neither A. nor B.
Answer Explanation

MCQs 9: Ramming masses are used for____________________?

Obtaining monolithic working faces Repairing construction of various furnace parts Both A. & B. Neither A. nor B.
Answer Explanation

MCQs 10: Pyrometric cone equivalent (PCE) of a refractory is the measure of its_________________?

Spalling resistance Fusion point Resistance to slag penetration Resistance to carbon monoxide attack
Answer Explanation

MCQs 11: Addition of grog in fireclay brick during its manufacture is advantageous, because it results in_____________________?

Less shrinkage in heating, decreased apparent porosity & increased specific gravity High strength & thermal spalling resistance Less addition of water to get a workable plasticity & lesser time required for drying the raw refractories and hence increased rate of production All A., B. and C.
Answer Explanation

MCQs 12: Use of higher percentage of lime for bonding silica bricks, reduces their__________________?

Strength Abrasion resistance Both A. & B. Neither A. nor B.
Answer Explanation

MCQs 13: Magnesite chrome refractories____________________?

Have better spalling resistance than chrome magnesite refractories Have very low thermal co-efficient of expansion Are not at all resistant to the corrosive action of iron oxide Have very low (50 kg/cm2) cold crushing strength (C.C.S.), and cannot be used in metalcase form
Answer Explanation

MCQs 14: ‘Super refractories’ are made from pure____________________?

Carbides Oxides Borides Nitrides
Answer Explanation

MCQs 15: Skull is not formed on the carbon blocks in the hearth of a blast furnace, when it becomes cold, because of its_______________?

Non-wetting characteristic High thermal conductivity High crushing strength None of these
Answer Explanation

MCQs 16: Maximum safe working temperature for fireclay bricks is about __________ °C?

1150 1300 1450 1550
Answer Explanation

MCQs 17: Which is the stable form of silica between 1470°C and the melting point 1713°C ?

Cristobalite Tridymite Quartz None of these
Answer Explanation

MCQs 18: Cold crushing strength of a refractory does not depend upon its ____________________?

Shape Composition Firing temperature Texture
Answer Explanation

MCQs 19: Thoria__________________?

Has high fusion temperature (> 3000°C) but poor resistance to thermal shock Has high resistance to basic slags Which is expensive & radioactive, is used in crucibles for melting high purity metals All A., B. and C.
Answer Explanation

MCQs 20: Chromite refractories are_____________________?

Acidic refractory Neutral refractory Basic refractory Fired at a temperature of 600°C only
Answer Explanation

Related Topics

About Us | Contact Us | Privacy Policy
ABOUT US
Category
Who We Are

TasDia Network, this platform not only provides you the best educational stuff but besides this, we are creating thousands of new ideas to making your signature and planning much more on a single platform.

© 2020-2023, TasDia Network

All rights of the publication are reserved by tasdia.com.