Materials and Construction Flashcards
The behaviour of visco-elastic material is time dependent. This behaviour is common in __________ materials.
non-crystalline organic polymeric.
Coke oven regenerators are made of __________ bricks.
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
Shock resisting steels should possess high
toughness
The purpose of nitriding the steel is to
harden its surface.
Ceramic recuperators are generally made of
silicon carbide.
Hammers and railway rails are normally made of
high carbon steel
Softness of silver can be converted into hardness by alloying it with small quantity of
copper & nickel
The addition of antimony in tin-based alloys improves its
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
prevent the action of water.
The impure iron (pig iron) that is tapped out from blast furnace contains about __________ percent carbon.
4
Invar used in thermocouples is an alloy of nickel and
iron
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
acetic acid
Constituents of stellite are
cobalt, chromium and tungsten.
Residual magnetism in steel for magnets is increased by the addition of
cobalt
Presence of nickel in steel improves its
corrosion resistance.
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
steel
Sulphur melting pit in the sulphuric acid plant is made of
steel or cement-brick lined.
The hardest material just prior to diamond in Mho’s scale is
corrundum
Percentage elongation of a material is a measure of its
ductility
Chlorination of benzene is done to produce benzene hexachloride (a pesticide) in a photochemical reactor lined with
lead or glass
Heavy duty bearings are usually made of
white metal
Dielectric strength of a material is
its capacity to withstand high voltage.
Which of the following stainless steels is non-magnetic ?
Austenitic
18-4-1 high speed steel contains 18%, 4% and 1% respectively of
tungsten, chromium and vanadium
Aluminum as a material of construction suffers from the disadvantage of
rather low tensile strength.
Babbit metal used for bearings is a____base alloy.
tin
Cast iron has very high
compressive strength
Liquid ammonia is shipped in __________ containers.
glass
Cermets are __________ materials.
refractory
Cast irons are generally specified by their
tensile strength
Austenitic manganese steel used for making jaws of crushing machines contains about __________ percent manganese.
12-14
White cast iron is not
malleable
Galvanised iron is
protected from rusting
German silver used for decorative purposes contains maximum percentage of
silver
copper
The metals occuring at the lower most position in the electromotive series
resist corrosion very strongly.
German silver in an alloy of
copper, nickel and zinc.
A suitable material of construction to use with fuming sulphuric acid is
monel
Which of the following crystal structures characterises the austenitic stainless steel?
Face centred cubic
Caustic soda is produced in a mercury cell having anode and cathode made respectively of moving mercury and
graphite and moving mercury.
Addition of __________ in steel can help in increasing the depth of hardness.
tungsten
Which of the following has the highest compressive strength ?
High carbon steel
Zinc is not used
as an alloying element in various bronzes.
Refined acetic acid storage vessel are made of
Aluminum
Addition of __________ to the steel helps in increasing the residual magnetism in steel used for making magnets.
cobalt
Constantan is an alloy of
Cu (55%) & Ni (45%).
