German silver is an alloy of
Silver and some impurities
Refined silver
Nickel, Copper and zinc
Nickel and copper
Correct Answer :
C. Nickel, Copper and zinc
Related Questions
Vanadium in high speed steels
Promotes decarburisation
Provides high hot hardness
Forms very hard carbides and thus increases wear resistance
Promotes retention of austenite
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
White cast iron contains carbon in the form of
Free carbon
Graphite
Cementite
White carbon
Chromium when added to steel __________ the tensile strength.
Does not effect
Decreases
Increases
None of these
The temperature at which ferromagnetic alpha iron transforms to paramagnetic alpha iron is
770°C
910°C
1050°C
Below recrystallisation temperature
There are fourteen atoms in a unit cell of
Body centred cubic space lattice
Face centred cubic space lattice
Close packed hexagonal space lattice
None of these
Eutectoid steel consists of
Wholly pearlite
Wholly austenite
Pearlite and ferrite
Pearlite and cementite
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
Machining properties of steel are improved by adding
Sulphur, lead, phosphorous
Silicon, aluminium, titanium
Vanadium, aluminium
Chromium, nickel
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
Cast iron is characterised by minimum of following percentage of carbon
0.2 %
0.8 %
1.3 %
2 %
Sulphur in pig iron tends to make it
Hard
Soft
Ductile
Tough
Crystal structure of a material is, generally, examined by
Naked eye
Optical microscope
Metallurgical microscope
X-ray techniques
Connecting rod is usually made of
Aluminium
Low carbon steel
Medium carbon steel
High carbon steel
Slow plastic deformation of metals under a constant stress is known as
Creep
Fatigue
Endurance
Plastic deformation
A material is said to be allotropic, if it has
Fixed structure at all temperatures
Atoms distributed in random pattern
Different crystal structures at different temperatures
Any one of the above
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
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
Which of the following alloys does not contain tin?
White metal
Solder admiralty
Fusible metal
Phosphor bronze
When the steel is normalised, its
Yield point increases
Ductility decreases
Ultimate tensile strength increases
All of these
Surveying tapes are made of a material having low coefficient of expansion and enough strength. The alloy used is
Silver metal
Duralumin
Hastelloy
Invar
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
Which of the following statement is true about brittle fracture?
High temperature and low strain rates favour brittle fracture
Many metals with hexagonal close packed (H.C.P) crystal structure commonly show brittle fracture
Brittle fracture is always preceded by noise
Cup and cone formation is characteristic for brittle materials
Eutectoid steel contains following percentage of carbon
0.02 %
0.3 %
0.63 %
0.8 %
Ductility of a material can be defined as
Ability to undergo large permanent deformations in compression
Ability to recover its original form
Ability to undergo large permanent deformations in tension
All of the above
Which of the following material has maximum ductility?
Mild steel
Copper
Nickel
Aluminium
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
A cold chisel is made of
Mild steel
Cast iron
HSS
High carbon
The property of a material due to which it breaks with little permanent distortion, is called
Brittleness
Ductility
Malleability
Plasticity
In grey cast iron, carbon is present in the form of
Cementite
Free carbon
Flakes
Spheroids