Corrosion resistance of steel is increased by addition of
Chromium and nickel
Sulphur, phosphorus, lead
Vanadium, aluminium
Tungsten, molybdenum, vanadium, chromium
Correct Answer :
A. Chromium and nickel
Related Questions
Lead is poured into the joint between two pipes. These pipes may be made of
Cast iron
Vitrified clay
Asbestos cement
Concrete
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
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
Following elements have face-centred cubic structure
Gamma iron (910° to 1400°C), Cu, Ag, Au, Al, Ni, Pb, Pt
Mg, Zn, Ti, Zr, Br, Cd
A iron (below 910°C and between 1400 to 1539°C), W
All of the above
Corundum contains more than 95%
Steel
Al2O3
SiO2
MgO
The crystal structure of gamma iron is
Body centered cubic
Face centred cubic
Hexagonal close packed
Cubic structure
The presence of hydrogen in steel causes
Reduced neutron absorption cross-section
Improved Weldability
Embrittlement
Corrosion resistance
Hardness of upper bainite (acicular structure) is about
RC 65
RC 48
RC 57
RC 80
The surface hardness of the following order is achieved by nitriding operation
600 VPN
1500 VPN
1000 to 1100 VPN
250 VPN
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
Which of the following constituents of steels is softest and least strong?
Austenite
Pearlite
Ferrite
Cementite
Which of the following material has maximum ductility?
Mild steel
Copper
Nickel
Aluminium
Which of the following is used for bearing liner?
Gun metal
Bronze
Bell metal
Babbitt metal
The percentage of carbon in cast iron varies from
0.1 to 0.5
0.5 to 1
1 to 1.7
1.7 to 4.5
The metal suitable for bearings subjected to heavy loads, is
Silicon bronze
White metal
Monel metal
Phosphor bronze
The machinability of steel is improved by adding
Nickel
Chromium
Nickel and chromium
Sulphur, lead and phosphorus
Large forgings, crank shafts, axles normally contain carbon up to
0.05 to 0.20 %
0.20 to 0.45 %
0.45 to 0.55 %
0.55 to 1.0 %
Dislocations in materials refer to the following type of defect
Point defect
Line defect
Plane defect
Volumetric defect
Which of the following alloys does not contain tin?
White metal
Solder admiralty
Fusible metal
Phosphor bronze
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
In induction hardening ________ is high.
Current
Voltage
Frequency
Temperature
Eutectoid steel contains following percentage of carbon
0.02 %
0.3 %
0.63 %
0.8 %
Cast iron is a
Ductile material
Malleable material
Brittle material
Tough material
The molecules in a solid move
In a random manner
In a haphazard way
In circular motion
Back and forth like tiny pendulums
Manganese in steel increases its
Tensile strength
Hardness
Ductility
Fluidity
The alloying element which can replace tungsten in high speed steels is
Nickel
Vanadium
Cobalt
Molybdenum
Nodular cast iron is produced by adding ________ to the molten cast iron.
Nickel
Chromium
Copper
Magnesium
Wrought iron
Is a ductile material
Can be easily forged or welded
Cannot stand sudden and excessive shocks
All of these
Aluminium bronze contains aluminium and copper in the ratio of
50 : 50
40 : 60
60 : 40
10 : 90
Which is the false statement about wrought iron? It has
High resistance to rusting and corrosion
High ductility
Ability of hold protective coating
Uniform strength in all directions