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
Correct Answer :
A. Hardening surface of work-piece to obtain hard and wear resistant surface
Related Questions
When a steel containing ________ 0.8% carbon is cooled slowly below the lower critical point, it consists of ferrite and pearlite.
Equal to
Less than
More than
None of these
The steel widely used for motor car crankshafts is
Nickel steel
Chrome steel
Nickel-chrome steel
Silicon steel
In full annealing, the hypo eutectoid steel is heated from 30°C to 50°C above the upper critical temperature and then cooled
In still air
Slowly in the furnace
Suddenly in a suitable cooling medium
Any one of these
Monel metal is an alloy of
Nickel and copper
Nickel and chromium
Nickel, Chromium and iron
Copper and chromium
The lower critical point for all steels is
600°C
700°C
723°C
913°C
The strength is the ability of a material to resist
Deformation under stress
Externally applied forces with breakdown or yielding
Fracture due to high impact loads
None of these
A reversible change in the atomic structure of the steel with a corresponding change in the properties is known as
Allotropic change
Recrystallisation
Heat treatment
Precipitation
The unique property of cast iron is its high
Malleability
Ductility
Surface finish
Damping characteristics
Blast furnace produces following by reduction of iron ore
Cast iron
Pig iron
Wrought iron
Malleable iron
Machining properties of steel are improved by adding
Sulphur, lead, phosphorous
Silicon, aluminium, titanium
Vanadium, aluminium
Chromium, nickel
Malleability of a material can be defined as
Ability to undergo large permanent deformations in compression
Ability to recover its original form
Ability to undergo large permanent deformations in tension
All of the above
Weld decay is the phenomenon found with
Cast iron
Mild steel
Nonferrous materials
Stainless steel
Bronze contains
70% copper and 30% zinc
90% copper and 10% tin
85 - 92% copper and rest tin with little lead and nickel
70 - 75% copper and rest tin
Cast iron is manufactured in
Blast furnace
Cupola
Open hearth furnace
Bessemer converter
The hardness of steel depends upon the
Amount of cementite it contains
Amount of carbon it contains
Contents of alloying elements
Method of manufacture of steel
An alloy of copper, tin and zinc is known as
Brass
Bronze
Gun metal
Muntz metal
Nimonic contains __________ percentage of nickel as that of Inconel.
Same
Less
More
None of these
Iron-carbon alloys containing carbon ________ 4.3% are known as hypereutectic cast irons.
Equal to
Less than
More than
None of these
Which of the following metal shrinks most from molten state to solid state?
Cast iron
Cast steel
Brass
Admiralty metal
The crystal of alpha iron is
Body centered cubic
Face centered cubic
Hexagonal close packed
Cubic structure
An important property of malleable cast iron in comparison to grey cast iron is the high
Compressive strength
Ductility
Carbon content
Hardness
Cupola produces following material
Cast iron
Pig iron
Wrought iron
Malleable iron
Steel with ________ carbon is known as hypo-eutectoid steel.
0.8 %
Below 0.8 %
Above 0.8 %
None of these
In grey cast iron, carbon is present in the form of
Cementite
Free carbon
Flakes
Spheroids
Chromium when added to steel __________ the tensile strength.
Does not effect
Decreases
Increases
None of these
Blast furnace is used to produce
Pig iron
Cast iron
Wrought iron
Steel
Combined carbon in iron makes the metal
Soft and gives coarse grained crystalline structure
Soft and gives a fine grained crystalline structure
Hard and gives a coarse grained crystalline structure
Hard and gives a fine grained crystalline structure
Grey cast iron
Contains 1.7 to 3.5% carbon in Free State and is obtained by the slow cooling of molten cast iron
Is also known as chilled cast iron is obtained by cooling rapidly. It is almost unmachinable
Is produced by annealing process. I is soft, tough and easily machined metal
Is produced by small additions o magnesium (or cerium) in the ladle Graphite is in nodular or spheroidal form and is well dispersed throughout the material
The correct sequence for descending order of machinability is
Grey cast iron, low carbon steel, wrought iron
Low carbon steel, grey cast iron, wrought iron
Wrought iron, low carbon steel, grey cast iron
Wrought iron, grey cast iron, low carbon steel
Compressive strength of grey cast iron in tonnes/cm is of the order of
35
57
710
1015