Addition of silicon to aluminium results in
Improvement of casting characteristics
Improvement of corrosion resistance
One of the best known age and precipitation hardening systems
Improving machinability
Correct Answer :
A. Improvement of casting characteristics
Related Questions
Age-hardening is related with
Stainless steel
Gun metal
German silver
Duralumin
The cupola is used to manufacture
Pig iron
Cast iron
Wrought iron
Steel
Silicon when added to copper improves
Machinability
Hardness
Hardness and strength
Strength and ductility
Sulphur in cast iron
Makes the iron soft and easily machinable
Increases hardness and brittleness
Make the iron white and hard
Aids fusibility and fluidity
Which of the following statements are true for annealing of steels?
Steels are heated to 500 to 700°C
Cooling is done slowly and steadily
Internal stresses are relieved
All of these
Quenching is not necessary when hardening is done by
Case hardening
Flame hardening
Nitriding
Any one of these
White cast iron has
Carbon in the form of carbide
Low tensile strength
High compressive strength
All of these
The hardness of steel increases if it contains
Austenite
Martensite
Pearlite
Cementite
The brown smoke during the operation of a Bessemer converter indicates that the
Air is burning out silicon and manganese
Silicon and manganese has burnt and carbon has started oxidising
The converter must be titled to remove the contents of the converter
The brown smoke does not occur during the operation of a Bessemer converter
The correct composition of Babbitt metal is
87.75% Sn, 4% Cu, 8% Sb, 0.25% Bi
90% Sn, 2% Cu, 4% Sb, 2% Bi, 2% Mg
87% Sn, 4% Cu, 8% Sb, 1% Al
82% Sn, 4% Cu, 8% Sb, 3% Al, 3% Mg
The alloy used for making electrical resistances and heating elements is
Nichrome
Invar
Magnin
Elinvar
A reversible change in the atomic structure of the steel with a corresponding change in the properties is known as
Allotropic change
Recrystallisation
Heat treatment
Precipitation
Addition of copper to aluminium results in
Improvement of casting characteristics
Improvement of corrosion resistance
One of the best known age and precipitation hardening systems
Improving machinability
The metal suitable for bearings subjected to light loads, is
Silicon bronze
White metal
Monel metal
Phosphor bronze
Age hardening is related to
Duralumin
Brass
Copper
Silver
Which of the following has a fine gold colour and is used for imitation jewellery?
Silicon bronze
Aluminium bronze
Gun metal
Babbitt metal
Chromium when added to steel __________ the tensile strength.
Does not effect
Decreases
Increases
None of these
The lower critical point for all steels is
600°C
700°C
723°C
913°C
Chromium 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
Foundry crucible is made of
Mild steel
German silver
Lead
Graphite
The temperature at which ferromagnetic alpha iron transforms to paramagnetic alpha iron is
770°C
910°C
1050°C
Below recrystallisation temperature
The percentage carbon content in wrought iron is about
0.02
0.1
02
0.4
Isotropic materials are those which have the same
Elastic properties in all directions
Stresses induced in all directions
Thermal properties in all directions
Electric and magnetic properties in all directions
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
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
Connecting rod is, usually, made from
Low carbon steel
High carbon steel
Medium carbon steel
High speed steel
Babbitt metal is a
Lead base alloy
Tin base alloy
Copper base alloy
Both (A) and (C) above
The portion of the blast furnace below its widest cross-section is called
Hearth
Stack
Bosh
Throat
The heat treatment process used for softening hardened steel is
Carburising
Normalising
Annealing
Tempering
Which of the following alloys does not contain tin?
White metal
Solder admiralty
Fusible metal
Phosphor bronze