Quenching is not necessary when hardening is done by
Case hardening
Flame hardening
Nitriding
Any one of these
Correct Answer :
C. Nitriding
Related Questions
In which of the following cases, consideration of creep is important
Flywheel of steam engine
Cast iron pipes
Cycle chains
Gas turbine blades
Grey cast iron has
Carbon in the form of free graphite
High tensile strength
Low compressive strength
All of these
The steel widely used for motor car crankshafts is
Nickel steel
Chrome steel
Nickel-chrome steel
Silicon steel
Basic solution is one which has pH value
Greater than 7
Equal to 7
Less than 7
pH value has nothing to do with basic solution
Shock resistance of steel is increased by adding
Nickel
Chromium
Nickel and chromium
Sulphur, lead and phosphorus
Aluminium bronze contains
94% aluminium, 4% copper and 0.5% Mn, Mg, Si and Fe
92.5% aluminium, 4% copper, 2% nickel, and 1.5% Mg
10% aluminium and 90% copper
90% magnesium and 9% aluminium with some copper
Constantan an alloy used in thermocouples is an alloy of
Copper and tin
Copper and zinc
Copper and iron
Copper and nickel
Tungsten in steel
Improves wear resistance, cutting ability and toughness
Refines grain size and produces less tendency to carburisation, improves corrosion and heat resistant properties
Improves cutting ability and reduces hardenability
Gives ductility, toughness, tensile strength and anticorrosion properties
The carbon in the pig iron varies from
0.1 to 0.5 %
0.5 to 1 %
1 to 5 %
5 to 10 %
The alloy used for making electrical resistances and heating elements is
Nichrome
Invar
Magnin
Elinvar
The ability of a material to resist softening at high temperature is known as
Creep
Hot tempering
Hot hardness
Fatigue
The maximum internal diameter of a blast furnace is about
3 m
6 m
9 m
12 m
In low carbon steels, presence of small quantities of sulphur improves
Weldability
Formability
Machinability
Hardenability
Age-hardening is related with
Stainless steel
Gun metal
German silver
Duralumin
The stiffness is the ability of a material to resist
Deformation under stress
Fracture due to high impact loads
Externally applied forces with breakdown or yielding
None of the above
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
Which of the following property is desirable for materials used in tools and machines?
Elasticity
Plasticity
Ductility
Malleability
Which of the following steel making process is being adopted at Rourkela (in India) Steel Plant?
Bessemer process
Open hearth process
Electric process
LD process
Ductility 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
Perminvar alloy having constant permeability is an alloy of
Nickel, copper and iron
Nickel, copper and zinc
Copper, nickel and antimony
Iron, zinc and bismuth
Addition of manganese to aluminium results in
Improvement of casting characteristics
Improvement of corrosion resistance
One of the best known age and precipitation hardening systems
Improving machinability
Vanadium in high speed steels
Promotes decarburisation
Provides high hot hardness
Forms very hard carbides and thus increases wear resistance
Promotes retention of austenite
Delta metal is an alloy of
Copper, zinc and iron
Iron, nickel and copper
Iron, lead and tin
Iron, aluminium and magnesium
Structural steel contains following principal alloying elements
Nickel, chromium and manganese
Tungsten, molybdenum and phosphorous
Lead, tin, aluminium
Zinc, sulphur, and chromium
A small percentage of boron is added to steel in order to
Increase hardenability
Reduce machinability
Increase wear resistance
Increase endurance strength
Gamma iron exits at following temperature
Room temperature
Near melting point
Between 1400°C and 1539°C
Between 910°C and 1400°C
Which is false statement about normalizing? Normalizing is done to
Refine grain structure
Reduce segregation in casting
Improve mechanical properties
Induce stresses
Duralumin contains
94% aluminium, 4% copper and 0.5% Mn, Mg, Si and Fe
92.5% aluminium, 40% copper, 2% nickel, and 1.5% Mg
10% aluminium and 90% copper
90% magnesium and 9% aluminium with some copper
An important property of malleable cast iron in comparison to grey cast iron is the high
Compressive strength
Ductility
Carbon content
Hardness
Delta-iron occurs between the temperature ranges of
400°C to 600°C
600°C to 900°C
900°C to 1400°C
1400°C to 1530°C