The percentage of carbon in grey iron castings usually varies between
0.5 to 1 %
1.2 %
2.5 to 4.5 %
5 to 7 %
Correct Answer :
C. 2.5 to 4.5 %
Related Questions
Induction hardening is the process of
Hardening surface of work-piece to obtain hard and wear resistant surface
Heating and cooling rapidly
Increasing hardness throughout
Inducing hardness by continuous process
Bell metal contains
70% copper and 30% zinc
90% copper and 10% ti
85 - 92% copper and rest tin with little lead and nickel
70 - 75% copper and rest tin
Grey 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 is obtained by cooling rapidly. It is almost unmachinable
Is produced by annealing process. I is soft, tough and easily machined metal
Is produced by small additions o magnesium (or cerium) in the ladle Graphite is in nodular or spheroidal form and is well dispersed throughout the material
The surface hardness of the following order is achieved by nitriding operation
600 VPN
1500 VPN
1000 to 1100 VPN
250 VPN
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
Admiralty brass used for steam condenser tubes contains copper and zinc in the following ratio
50 : 50
30 : 70
70 : 30
40 : 60
Hardness of lower bainite (tempered martensite) is about
RC 65
RC 48
RC 57
RC 80
High carbon steel carries carbon percentage
0.1 to 0.3 %
0.3 to 0.6 %
0.6 to 0.8 %
0.8 to 1.5 %
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
The ratio of the volume occupied by the atoms to the total volume of the unit cell is called
Coordination number
Atomic packing factor
Space lattice
None of these
German silver contains
1% silver
2.5% silver
5% silver
10% silver
The ultimate tensile strength of low carbon steel by working at a high strain rate will
Decrease
Increase
Remain constant
First increase and then decrease
Cartridge brass can be
Cold rolled into sheets
Drawn into wires
Formed into tube
Any one of these
Process of Austempering results in
Formation of bainite structure
Carburised structure
Martenistic structure
Lamellar layers of carbide distributed throughout the structure
The compressive strength of cast iron is ________ that of its tensile strength.
Equal to
Less than
More than
None of these
Nickel when added to copper improves
Machinability
Hardness
Hardness and strength
Strength and ductility
The percentage of carbon in low carbon steel is
0.05 %
0.15 %
0.3 %
0.5 %
Cast iron has
High tensile strength
Its elastic limit close to the ultimate breaking strength
High ductility
All of the above
The addition of which of the following improves machining of copper?
Sulphur
Vanadium
Tin
Zinc
Tungsten in high speed steel provides
Hot hardness
Toughness
Wear resistance
Sharp cutting edge
Brass is an alloy of
Copper and zinc
Copper and tin
Copper, tin and zinc
None of these
Which is false statement about case hardening? Case hardening is done by
Electroplating
Cyaniding
Induction hardening
Nitriding
Which of the following is not the correct method of increasing fatigue limit?
Shot peening
Nitriding of surface
Cold working
Surface decarburisation
Quenching is not necessary when hardening is done by
Case hardening
Flame hardening
Nitriding
Any one of these
Cast iron is manufactured in
Blast furnace
Cupola
Open hearth furnace
Bessemer converter
Which of the following material has nearly zero coefficient of expansion?
Stainless steel
High speed steel
Invar
Heat resisting steel
The blade of a power saw is made of
Boron steel
High speed steel
Stainless steel
Malleable cast iron
According to Indian standard specifications, plain carbon steel designated by 40 C8 means that the carbon content is
0.04 %
0.35 to 0.45 %
0.4 to 0.6 %
0.6 to 0.8 %
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
Corrosion resistance of steel is increased by adding
Chromium and nickel
Nickel and molybdenum
Aluminium and zinc
Tungsten and sulphur