Balls for ball bearings are made of
Cast iron
Mild steel
Stainless steel
Carbonchrome steel
Correct Answer :
D. Carbonchrome steel
Related Questions
Which one of the following metals would work-harden more quickly than the others?
Copper
Brass
Lead
Silver
The alloying element which can replace tungsten in high speed steels is
Nickel
Vanadium
Cobalt
Molybdenum
The blade of a power saw is made of
Boron steel
High speed steel
Stainless steel
Malleable cast iron
Nodular cast iron is produced by adding ________ to the molten cast iron.
Nickel
Chromium
Copper
Magnesium
The type of space lattice found in alpha-iron is
Face centred cubic space lattice
Body centred cubic space lattice
Close packed hexagonal space lattice
None of these
The presence of sulphur in pig iron makes
It easily machinable
It brittle
It hard
The casting unsound
Alnico, an alloy used extensively for permanent magnets contains iron, nickel, aluminium and cobalt in the following ratio
50 : 20 : 20 : 10
40 : 30 : 20 : 10
50 : 20 : 10 : 20
30 : 20 : 30 : 20
Compressive strength of grey cast iron in tonnes/cm is of the order of
35
57
710
1015
Y-alloy contains
3.5 to 4.5% copper, 0.4 to 0.7% magnesium, 0.4 to 0.7% manganese and rest aluminium
3.5 to 4.5% copper, 1.2 to 1.7% manganese, 1.8 to 2.3% nickel, 0.6% each of silicon, magnesium and iron, and rest aluminium
4 to 4.5% magnesium, 3 to 4% copper and rest aluminium
5 to 6% tin, 2 to 3% copper and rest aluminium
In the lower part of the blast furnace (zone of fusion), the temperature is
400° to 700°C
800°C to 1000°C
1200°C to 1300°C
1500°C to 1700°C
In low carbon steels, ________ raises the yield point and improves the resistance to atmospheric corrosion.
Sulphur
Phosphorus
Manganese
Silicon
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
The percentage of carbon in pig iron varies from
0.1 to 1.2%
1.5 to 2.5%
2.5 to 4%
4 to 4.5%
In grey cast iron, carbon is present in the form of
Cementite
Free carbon
Flakes
Spheroids
When the steel is normalised, its
Yield point increases
Ductility decreases
Ultimate tensile strength increases
All of these
Which of the following elements does not impart hardness to steel?
Copper
Chromium
Nickel
Silicon
In basic Bessemer process, the furnace is lined with
Silica bricks
A mixture of tar and burnt dolomite bricks
Both (A) and (B)
None of these
Which of the following material has nearly zero coefficient of expansion?
Stainless steel
High speed steel
Invar
Heat resisting steel
When low carbon steel is heated up to lower 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
Babbitt metal is a
Lead base alloy
Tin base alloy
Copper base alloy
Both (A) and (C) above
Stress relaxation is the phenomenon
In which parts are not loaded
In which stress remains constant on increasing load
In which deformation tends to loosen the joint and produces a stress reduced
Stress reduces on increasing load
Corrosion resistance of steel is increased by addition of
Chromium and nickel
Sulphur, phosphorus, lead
Vanadium, aluminium
Tungsten, molybdenum, vanadium, chromium
The property of a material which enables it to retain the deformation permanently, is called
Brittleness
Ductility
Malleability
Plasticity
Balls for ball bearings are made of
Cast iron
Mild steel
Stainless steel
Carbonchrome steel
Which of the following is not the correct method of increasing fatigue limit?
Shot peening
Nitriding of surface
Cold working
Surface decarburisation
In induction hardening ________ is high.
Current
Voltage
Frequency
Temperature
A material is known as allotropic or polymorphic if it
Has a fixed structure under all conditions
Exists in several crystal forms at different temperatures
Responds to heat treatment
Has its atoms distributed in a random pattern
Phosphor bronze contains
0.5% of phosphorous
1% phosphorous
2.5% phosphorous
None of the above
An alloy of copper, tin and zinc is known as
Brass
Bronze
Gun metal
Muntz metal
The metallic structure of mild steel is
Body centred cubic
Face centred cubic
Hexagonal close packed
Cubic structure