Elinvar, an alloy used in precision instruments, hair springs for watches, etc. contains the following element as principal alloying element
Iron
Copper
Aluminium
Nickel
Correct Answer :
D. Nickel
Related Questions
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
Cobalt in steel
Improves wear resistance, cutting ability and toughness
Refines grain size and produces less tendency to carburisation, improve corrosion and heat resistant proper ties
Improves cutting ability and reduce hardenability
Gives ductility, toughness, tensile strength and anti corrosion property
The toughness of a material __________ when it is heated.
Remain same
Decreases
Increases
None of these
By severely deforming a metal in a particular direction it becomes
Ductile
Malleable
Homogeneous
Anisotropic
Paramagnetic alpha iron changes to gamma iron at
770°C
910°C
1440°C
1539°C
Which of the following property is desirable for materials used in tools and machines?
Elasticity
Plasticity
Ductility
Malleability
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
Corrosion resistance of steel is increased by addition of
Chromium and nickel
Sulphur, phosphorus, lead
Vanadium, aluminium
Tungsten, molybdenum, vanadium, chromium
In malleable iron, carbon is present in the form of
Cementite
Free carbon
Flakes
Nodular aggregates of graphite
Constantan an alloy used in thermocouples is an alloy of
Copper and tin
Copper and zinc
Copper and iron
Copper and nickel
Pick up wrong statement about wrought iron
It contains carbon of the order of 0 to 0.25%
It melts at 1535°C
It is very soft and ductile
It is made by adding suitable percentage of carbon to molten iron and subjecting the product to repeated hammering and rolling.
Which of the following has highest specific strength of all structural materials?
Magnesium alloys
Titanium alloys
Chromium alloys
Magnetic steel alloys
If a refractory contains high content of silicon, it means refractory is
Acidic
Basic
Neutral
Brittle
The silicon steel is widely used for
Connecting rods
Cutting tools
Generators and transformers in the form of laminated cores
Motor car crankshafts
The composition of silver solder is
Silver, copper, zinc
Silver, tin, nickel
Silver, lead, zinc
Silver, copper, aluminium
Recrystallisation temperature is one
At which crystals first start forming from molten metal when it is cooled
At which new spherical crystals first begin to form from the old deformed one when a strained metal is heated
At which change of allotropic form takes place
At which crystals grow bigger in size
When low carbon steel is heated up to upper critical temperature
There is no change in grain size
The average grain size is a minimum
The grain size increases very rapidly
The grain size first increases and then decreases very rapidly
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
The most effective inhibitor of grain growth, when added in small quantities is
Carbon
Vanadium
Manganese
Cobalt
Which of the following constituents of steels is softest and least strong?
Austenite
Pearlite
Ferrite
Cementite
The hardness of steel primarily depends on
Percentage of carbon
Percentage of alloying elements
Heat treatment employed
Shape of carbides and their distribution in iron
Carbon in iron is an example of
Substitutional solution
Interstitial solid solution
Intermetallic compounds
All of the above
The material in which the atoms are arranged regularly in some directions but not in others, is called
Amorphous material
Mesomorphous material
Crystalline material
None of these
The aluminium alloy made by melting aluminium with 2 to 10% magnesium and 1.75% copper is called
Duralumin
Y-alloy
Magnalium
Hindalium
Which of the following has a fine gold colour and is used for imitation jewellery?
Silicon bronze
Aluminium bronze
Gun metal
Babbitt metal
Delta metal is an alloy of
Copper, zinc and iron
Iron, nickel and copper
Iron, lead and tin
Iron, aluminium and magnesium
The percentage carbon content in wrought iron is about
0.02
0.1
02
0.4
Which of the following element results in presence of free graphite in C.I.?
Carbon
Sulphur
Silicon
Manganese
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
The cupola is used to manufacture
Pig iron
Cast iron
Wrought iron
Steel