Q.1
Cermets are combination of ceramic and metallic materials due to which they have high strength & resistance to high temperature. Cermets are used in the
Q.2
Basic bricks are not made of
Q.3
Chromite refractories are
Q.4
Carbon refractory blocks
Q.5
Which of the following is not an acidic refractory?
Q.6
Alumina-graphite bricks are used for lining the
Q.7
Maximum water percentage in refractory mix meant for hand moulding may be as high as __________ percent.
Q.8
An ideal refractory should have high
Q.9
Which is the stable form of silica between 1470°C and the melting point 1713°C ?
Q.10
__________ bricks should not be used in oxidising atmosphere.
Q.11
__________ bricks are used in the burning zone of a cement rotary kiln.
Q.12
Silica refractories are not used in
Q.13
High alumina refractories are used in the
Q.14
Most Cermets, which normally have high thermal conductivity and high thermal shock resistance, comprises of ceramic & metallic components of __________ percent respectively.
Q.15
Presence of MgO in alumino-silicate refractories __________ its refractoriness.
Q.16
Pure bauxite is the best raw material for the manufacture of high alumina refractories, in which maximum alumina content can be as high as __________ percent.
Q.17
Maximum shrinkage in volume occurring during burning/firing of dried refractories may be as high as __________ percent.
Q.18
Furnace atmosphere for softening temperature determination of refractories (in which segar cones are placed) should be
Q.19
Porosity of silica bricks varies from __________ percent.
Q.20
Maximum alumina content in high alumina refractory can be as high as __________ percent.
Q.21
High thermal conductivity of a refractory material is not important, when it is to be used in the
Q.22
Thermal diffusivity of a refractory brick is high, when its __________ is high.
Q.23
Test piece for determination of RUL of a refractory is heated in a/an
Q.24
Lower wall courses of soaking pits are made of __________ bricks to avoid the action of molten slag & scale.
Q.25
Fusion point of a basic refractory material is
Q.26
Which is not a natural insulating material?
Q.27
Periclase refractory contains mainly
Q.28
In panel test for spalling resistance, the average face temperature of panel assembly is maintained at __________ °C for 24 hours.
Q.29
Pyrometric cone equivalent (PCE) value (Segar cone) of 'superduty refractories' is more than 33 which corresponds to a temperature of __________ °C.
Q.30
Spalling of silica bricks occurs due to abrupt volume changes, when it is cooled below a temperature of __________ °C.
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