(4) Materials and Construction Flashcards
The behaviour of visco-elastic material is time dependent. This behaviour is common in __________ materials.
-non-crystalline solid
-crystalline
-rubberry
-non-crystalline organic polymeric.
non-crystalline organic polymeric.
Coke oven regenerators are made of __________ bricks.
-fire clay
-silica
-low thermal conductivity
-high electrical conductivity
-fire clay
Which of the following is universally employed as the low expansion metal in the bimetallic thermometer, which is an iron-nickel alloy containing 36% nickel and has very low co-efficient of expansion (l/20th of ordinary metals) ?
-Invar
-Constantan
-Chromel
-Alume
Invar
Shock resisting steels should possess high
-hardness
-toughness
-tensile strength
-wear resistance
toughness
The purpose of nitriding the steel is to
-harden its surface.
-soften its surface.
-improve its reliability.
-none of these.
-harden its surface.
Ceramic recuperators are generally made of
-silicon carbide.
-calcium carbide.
-fireclay bricks.
-high alumina bricks.
-silicon carbide.
Hammers and railway rails are normally made of
-mild steel
-dead mild steel
-medium carbon steel
-high carbon steel
-high carbon steel
Softness of silver can be converted into hardness by alloying it with small quantity of
-copper & nickel
-zinc
-aluminium
-tin
-copper & nickel
The addition of antimony in tin-based alloys improves its
-rupture strength and hot hardness.
-impact strength and bonding strength.
-deformation resistance.
-wear resistance
-deformation resistance.
The melleability of a material is the property by virtue of which it can be rolled or hammered into thin sheets. Which of the following materials has the miximum malleability ?
-Lead
-Copper
-Aluminium
-Wrought iron
Lead
The main purpose of galvanising iron sheets is to
-harden the surface.
-increase its glossiness and lustre.
-prevent the action of water.
-prevent the action of oxygen.
-prevent the action of water.
The impure iron (pig iron) that is tapped out from blast furnace contains about __________ percent carbon.
0.2
2
4
8
4
Invar used in thermocouples is an alloy of nickel and
-iron
-copper
-chromium
-lead
iron
Nickel (56%) and molybdenum (17%) alloys are called
-monel
-hastealloy C
-inconel
-bronzes
hastealloy C
Lead pipes are not safe for carrying drinking water because water containing dissolved oxygen attacks lead thereby forming poisonous Pb (OH)2. Lead pipes are readily corroded by
-dilute HCI
-acetic acid
-concentrated H2SO4
-none of these
-acetic acid
Constituents of stellite are
-zinc, copper and nickel.
-cobalt, chromium and tungsten.
-zinc, aluminium and nickel.
-nickel, cobalt and vanadium.
-cobalt, chromium and tungsten.
Residual magnetism in steel for magnets is increased by the addition of
-nickel
-cobalt
-tungsten
-chromium
cobalt
Presence of nickel in steel improves its
-corrosion resistance.
-cutting ability.
-wear resistance.
a-ll (a), (b) and (c).
corrosion
Cementite is
-Fe3C chemically.
-a compound of carbon and iron.
-characterised by an orthorhombic crystal structure.
-all (a), (b) and (c).
-all (a), (b) and (c).
Acetylene gas holder is made of
-copper
-cast iron
-steel
-monel metal
-steel
Sulphur melting pit in the sulphuric acid plant is made of
-lead lined stainless steel.
-cast iron.
-steel or cement-brick lined.
-hard wood.
-steel or cement-brick lined.
The hardest material just prior to diamond in Mho’s scale is
-topax
-carborundum
-corrundum
-calcite
corrundum
Percentage elongation of a material is a measure of its
-ductility
-brittleness
-toughness
-malleability
-ductility
Chlorination of benzene is done to produce benzene hexachloride (a pesticide) in a photochemical reactor lined with
-karbate
-lead or glass
-fireclay bricks
-PVC
-lead or glass
Heavy duty bearings are usually made of
-white metal
-phosphorous bronze
-monel
-zinc
-white metal
Dielectric strength of a material is
-its energy stroage capacity.
-a magnetic property.
-its capacity to resist the flow of current.
-its capacity to withstand high voltage.
-its capacity to withstand high voltage.
Which of the following stainless steels is non-magnetic ?
-Ferritic
-Martensitic
-Austenitic
-None of these
Austenitic
18-4-1 high speed steel contains 18%, 4% and 1% respectively of
-tungsten, vanadium and chromium
-tungsten, chromium and vanadium
-vanadium, chromium and tungsten
-chromium, tungsten and vanadium
-tungsten, chromium and vanadium
Aluminium as a material of construction suffers from the disadvantage of
-very high cost.
-rather low tensile strength.
-very low strength to weight ratio.
-scarce availability.
-rather low tensile strength.
Babbit metal used for bearings is a____base alloy.
-tin
-lead
-aluminium
-copper
-tin
18/8 steel is a/an __________ stainless steel.
-austenitic
-ferritic
-martensitic
-none of these
-austenitic
Cast iron has very high
-compressive strength
-ductility
-shock resistance
-resistance to brittleness
-compressive strength
Liquid ammonia is shipped in __________ containers.
-steel
-aluminium
-glass
-lead lined
glass
Cermets are __________ materials.
-refractory
-reinforced
-abrasive
-fully metallic
refractory
Cast irons are generally specified by their
-carbon content
-tensile strength
-hardness
-manufacturing process
-tensile strength
Austenitic manganese steel used for making jaws of crushing machines contains about __________ percent manganese.
1.5-2
3.5-4.5
7-9
12-14
12-14
White cast iron is not
-malleable
-whitish in color
-brittle
-strong and hard
malleable
Galvanised iron is
-harder
-protected from rusting
-alumina coated iron
-none of these
-protected from rusting
German silver used for decorative purposes contains maximum percentage of
-silver
-copper
-zinc
-nickel
-copper
The metals occuring at the lower most position in the electromotive series
-do not resist corrosion.
-resist corrosion very strongly.
-are very brittle.
-are heat insulators.
-resist corrosion very strongly.