Iron-carbon alloys containing carbon ________ 4.3% are known as hypereutectic cast irons.
Equal to
Less than
More than
None of these
Correct Answer :
C. More than
Related Questions
Which of the following represents the allotropic forms of iron?
Alpha iron, beta iron and gamma iron
Alpha iron and beta iron
Body centred cubic iron and face centred cubic iron
Alpha iron, gamma from and delta iron
Induction hardening is the process of
Hardening surface of work-piece to obtain hard and wear resistant surface
Heating and cooling rapidly
Increasing hardness throughout
Inducing hardness by continuous process
A material is said to be allotropic, if it has
Fixed structure at all temperatures
Atoms distributed in random pattern
Different crystal structures at different temperatures
Any one of the above
According to Indian standard specifications, SG 400/15 means
Spheroidal graphite cast iron with B.H.N. 400 and minimum tensile strength 15 MPa
Spheroidal graphite cast iron with minimum tensile strength 400 MPa and 15 percent elongation
Spheroidal graphite cast iron with minimum compressive strength 400 MPa and 15 percent reduction in area
None of the above
Eutectoid steel contains following percentage of carbon
0.02 %
0.3 %
0.63 %
0.8 %
The crystal structure of brass is
F.C.C.
B.C.C.
H.C.P.
Orthorhombic crystalline structure
The purpose of heat treatment is to
Relieve the stresses set up in the material after hot or cold working
Modify the structure of the material
Change grain size
Any one of these
According to Indian standard specifications, plain carbon steel designated by 40 C8 means that the carbon content is
0.04 %
0.35 to 0.45 %
0.4 to 0.6 %
0.6 to 0.8 %
The hardness of steel increases if it contains
Austenite
Martensite
Pearlite
Cementite
The percentage of carbon in pig iron varies from
0.1 to 1.2%
1.5 to 2.5%
2.5 to 4%
4 to 4.5%
In nodular iron, graphite is in the form of
Cementite
Free carbon
Flakes
Spheroids
Depth of hardness of steel is increased by addition of
Nickel
Chromium
Tungsten
Vanadium
Which of the following material has nearly zero coefficient of expansion?
Stainless steel
High speed steel
Invar
Heat resisting steel
White cast iron contains carbon in the form of
Free carbon
Graphite
Cementite
White carbon
Macrostructure of a material is, generally, examined by
Naked eye
Optical microscope
Metallurgical microscope
X-ray techniques
In which of the following cases, consideration of creep is important
Flywheel of steam engine
Cast iron pipes
Cycle chains
Gas turbine blades
Wrought iron is
Hard
High in strength
Highly resistant to corrosion
Heat treated to change its properties
The ability of a material to absorb energy in the plastic range is called
Resilience
Creep
Fatigue strength
Toughness
Iron is
Paramagnetic
Ferromagnetic
Ferroelectric
Dielectric
Beryllium bronze contains
60% copper and 40% beryllium
80% copper and 20% beryllium
97.75% copper and 2.25% beryllium
99% copper and 1% beryllium
When filing or machining cast iron makes our hands black, then it shows that ________ is present in cast iron.
Cementite
Free graphite
Both A and B
None of these
Quenching is not necessary when hardening is done by
Case hardening
Flame hardening
Nitriding
Any one of these
Stress relaxation is the phenomenon
In which parts are not loaded
In which stress remains constant on increasing load
In which deformation tends to loosen the joint and produces a stress reduced
Stress reduces on increasing load
Babbitt metal is a
Lead base alloy
Tin base alloy
Copper base alloy
Both (A) and (C) above
In basic Bessemer process, the furnace is lined with
Silica bricks
A mixture of tar and burnt dolomite bricks
Both (A) and (B)
None of these
Taps dies and drills contain carbon
Below 0.5 %
Below 1 %
Above 1 %
Above 2.2 %
If a refractory contains high content of silicon, it means refractory is
Acidic
Basic
Neutral
Brittle
In high speed steels, manganese is used to tougher the metal and to increase its
Yield point
Critical temperature
Melting point
Hardness
Machining properties of steel are improved by adding
Sulphur, lead, phosphorous
Silicon, aluminium, titanium
Vanadium, aluminium
Chromium, nickel
Points of arrest for iron correspond to
Stages at which allotropic forms change
Stages at which further heating does not increase temperature for some time
Stages at which properties do not change with increase in temperature
There is nothing like points of arrest