11. Test piece for determination of RUL of a refractory is heated in a/an
oxidising atmosphere
reducing atmosphere
electric furnace
neutral atmosphere
✅ The correct answer is option C.
Refractory Technology MCQs
12. Walls, roofs & combustion chambers of annealing furnaces are made of __________ bricks.
high duty fireclay
silica
mullite
carborundum
✅ The correct answer is option A.
13. The linear thermal expansion of __________ bricks upto 1000 °C is very low of the order of ≤ 0.5 percent.
fireclay
silica
magnesite
corundum
✅ The correct answer is option A.
14. Faster rate of drying of moulded refractories results in high __________ of refractories.
green strength
voids
shrinkage
both (b) and (c)
✅ The correct answer is option D.
15. High density refractory bricks have lower
spalling resistance.
thermal conductivity.
fusion point.
slag penetration resistance.
✅ The correct answer is option A.
16. Magnesite chrome bricks are used in the
roof lining of basic open hearth & other basic furnaces.
reheating furnaces.
soaking pits.
all (a), (b) and (c).
✅ The correct answer is option D.
17. Chemically, mullite refractories is
3Al2O3.2SiO2
Al2O3
ZrSO4
ThO2
✅ The correct answer is option A.
18. Refractory materials are never used in the construction of
segar cones
orton cones
pressure vessels
ovens & retorts
✅ The correct answer is option C.
19. 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
✅ The correct answer is option A.
20. Chrome magnesite brick is not used for lining the
hearth of soaking pits.
bottom hearth of reheating furnace.
coke oven regenerator.
burning zone of limestone rotary kilns.
✅ The correct answer is option C.