The heat treatment process used for softening hardened steel is
Carburising
Normalising
Annealing
Tempering
Correct Answer :
D. Tempering
Related Questions
Slow plastic deformation of metals under a constant stress is known as
Creep
Fatigue
Endurance
Plastic deformation
Pearlite is a combination of
Ferrite and cementite
Cementite and gamma iron
Ferrite and austenite
Ferrite and iron graphite
Structural steel contains following principal alloying elements
Nickel, chromium and manganese
Tungsten, molybdenum and phosphorous
Lead, tin, aluminium
Zinc, sulphur, and chromium
Which of the following impurity in cast iron makes it hard and brittle?
Silicon
Sulphur
Manganese
Phosphorus
The alloying element which reduces the formation of iron sulphide in steel is
Chromium
Nickel
Vanadium
Manganese
Compressive strength of grey cast iron in tonnes/cm is of the order of
35
57
710
1015
Addition of copper to aluminium results in
Improvement of casting characteristics
Improvement of corrosion resistance
One of the best known age and precipitation hardening systems
Improving machinability
The maximum internal diameter of a blast furnace is about
3 m
6 m
9 m
12 m
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
Cast iron has
High tensile strength
Its elastic limit close to the ultimate breaking strength
High ductility
All of the above
Which of the following is an amorphous material?
Mica
Silver
Lead
Glass
In nodular iron, graphite is in the form of
Cementite
Free carbon
Flakes
Spheroids
Normalising of steel is done to
Refine the grain structure
Remove strains caused by cold working
Remove dislocations caused in the internal structure due to hot working
All of the above
Monel metal contains
63 to 67% nickel and 30% copper
88% copper and 10% tin and rest zinc
Alloy of tin, lead and cadmium
Malleable iron and zinc
The coordination number of a face centred cubic space lattice is
Six
Twelve
Eighteen
Twenty
Age-hardening is related with
Stainless steel
Gun metal
German silver
Duralumin
The ability of a material to resist softening at high temperature is known as
Creep
Hot tempering
Hot hardness
Fatigue
In high speed steels, manganese is used to tougher the metal and to increase its
Yield point
Critical temperature
Melting point
Hardness
Iron-carbon alloys containing 1.7 to 4.3% carbon are known as
Eutectic cast irons
Hypoeutectic cast irons
Hypereutectic cast irons
None of these
When elements like nickel, chromium, copper and molybdenum are added to the molten cast iron, it produces
White cast iron
Nodular cast iron
Malleable cast iron
Alloy cast iron
Crystal structure of a material is, generally, examined by
Naked eye
Optical microscope
Metallurgical microscope
X-ray techniques
Tungsten in high speed steel provides
Hot hardness
Toughness
Wear resistance
Sharp cutting edge
White 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 and is obtained by cooling rapidly. It is almost unmachinable
Is produced by annealing process. It is soft, tough and easily machined metal
Is produced by small additions of magnesium (or creium) in the ladle. Graphite is in nodular or spheroidal form and is well dispersed throughout the material
Which is false statement about properties of aluminium?
Modulus of elasticity is fairly low
Wear resistance is very good
Fatigue strength is not high
Creep strength limits its use to fairly low temperatures
Corrosion resistance of steel is increased by adding
Chromium and nickel
Nickel and molybdenum
Aluminium and zinc
Tungsten and sulphur
Addition of silicon to aluminium results in
Improvement of casting characteristics
Improvement of corrosion resistance
One of the best known age and precipitation hardening systems
Improving machinability
Specify the sequence correctly
Grain growth, recrystallisation, stress relief
Stress relief, grain growth, recrystallisation
Stress relief, recrystallisation, grain growth
Grain growth, stress relief, recrystallisation
The carbon in the pig iron varies from
0.1 to 0.5 %
0.5 to 1 %
1 to 5 %
5 to 10 %
The unit cells
Contain the smallest number of atoms which when taken together have all the properties of the crystals of the particular metal
Have the same orientation and their similar faces are parallel
May be defined as the smallest parallelepiped which could be transposed in three coordinate directions to build up the space lattice
All of the above
The main alloying elements high speed steel in order of increasing proportion are
Vanadium, chromium, tungsten
Tungsten, titanium, vanadium
Chromium, titanium, vanadium
Tungsten, chromium, titanium