matl of 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 malleability 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 maximum malleability?
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
Nickel (56%) and molybdenum (17%) alloys are called
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
acetic acid
Residual magnetism in steel for magnets is increased by the addition of
cobalt
Constituents of stellite are
cobalt, chromium and tungsten.
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).
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
Aluminium as a material of construction suffers from the disadvantage of
rather low tensile strength.
Babbit metal used for bearings is a____base alloy.
tin
18/8 steel is a/an __________ stainless steel.
austenitic
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
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
aluminium
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%).
Babbit metals used for making bearings are
tin or lead based alloys.
Pipes for bi-cycle frames are made of __________ steel.
cold rolled
Which of the following materials may prove unsuitable for handling acetic acid (glacial & anhydrous) at 40°C ?
Brass, cast iron, mild steel and tin.
Interchain forces are the weakest in case of
both rubber & elastomers
__________ possesses viscoelastic properties.
Rubber
Steel tower used for the storage of oleum
need not be lined.
Plastics are
non-biodegradable.
Acetaldehyde is produced by hydration of acetylene in a sulphuric acid solution of mercuric sulphate. Hydration tower is made of
rubber lined mild steel
Wood is corroded by
hydrochloric acid
SO2 (dry or wet)
chlorine (dry or wet)
all (a), (b) and (c)
Brass is an alloy of
copper and zinc
Lead
can not be work hardened.
Photographic plates are coated with
silver halide
Cast iron has
elastic limit close to ultimate breaking strength.
Locomotive boiler tubes are made of __________ alloys.
arsenic copper
Slow and progressive deformation of a material with time under constant stress is called
creep
Which of the following heat treatment processes is used for softening the hardened material ?
Tempering
Which of the following mechanical properties of a material is most structure insensitive ?
Modulus of elasticity (young’s modulus).
Mercury is transported in metal containers made of
iron
Which of the following would not be a suitable material of construction for handling aqueous hydrofluoric acid (HF) at 100°C ?
Stainless steel
Which of the following has the least carbon percentage ?
Wrought iron
The range of Mho’s scale of hardness is from
l to10
Which of the following pairs of elements may form an alloy ?
Iron & carbon
SO3 is absorbed using H2SO4 in a
packed steel tower lined with acid proof bricks.
Carbon percentage in medium carbon steel is around
0.35 to 0.5
The preferred material of construction for storage tanks for 98% sulphuric acid is
lead
The fermentor used for the production of ethyl alcohol from molasses is made of
copper bearing steel
Super conductors are those substances, which
offer no resistance to current flow.
Cermets are used for making
cutting tools
abrasives
both (a) & (b)
The formation of oxide film on a metal due to atmospheric exposure reduces its
creep limit
A hardened steel essentially contains
martensite
Thermal shield used in high powered nuclear reactor to protect the walls of the reactor from radiation damage is made of
steel
Silico-manganese steels (containing 0.7% Mn, 0.5% C and 2% Si)
are used for leaf and coiled springs.
Which of the following is not a copper based alloy with nickel ?
Inconel
Which of the following alloys does not contain nickel ?
Babbit metal
An elastic behaviour of materials is expressed in terms of
relaxation time
Pure nickel is
ferromagnetic at room temperature.
In drop forging process, the forging is done by dropping the __________ at high velocity.
die with hammer
Which of the following is not an alloy of copper and tin ?
Monel metal
__________ is never shipped in glass carboys.
Ammonia
Lead is
used as a shock absorber (in mattress form) between the foundation and steel framework of skyscrapper buildings.
Nitriding of steel is done (in electric furnace) at __________ °C.
510
Addition of 2% nickel in steel makes it suitable for making
boiler plates, rivets etc.
The softest material just next to talc in the Mhos scale is
gypsum
Fatigue strength of a material increases by
under stressing the specimen
Specify the material of construction suitable for handling concentrated HNO3 at 100°C.
High silicon iron, Kel-F and teflon
Aluminium storage vessel can be used to store
none of these
Silicone rubber is not resistant to the corrosive action of
sulphuric acid (95%)
ether
both (b) and (c)
Which metal is protected by the layer of its own oxide ?
Aluminium
