Vanadium in high speed steels
Promotes decarburisation
Provides high hot hardness
Forms very hard carbides and thus increases wear resistance
Promotes retention of austenite
Correct Answer :
C. Forms very hard carbides and thus increases wear resistance
Related Questions
Brass contains
70% copper and 30% zinc
90% copper and 10% tin
85 - 92% copper and rest tin with little lead and nickel
70 - 75% copper and rest tin
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
Which of the following impurity in cast iron makes it hard and brittle?
Silicon
Sulphur
Manganese
Phosphorus
The purpose of heat treatment is to
Relieve the stresses set up in the material after hot or cold working
Modify the structure of the material
Change grain size
Any one of these
Combined carbon in iron makes the metal
Soft and gives coarse grained crystalline structure
Soft and gives a fine grained crystalline structure
Hard and gives a coarse grained crystalline structure
Hard and gives a fine grained crystalline structure
The following types of materials are usually the most ductile
Face centred cubic lattice
Body centred cubic lattice
Hexagonal close packed lattice
All of the above
Tungsten 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
The material in which the atoms are arranged regularly in some directions but not in others, is called
Amorphous material
Mesomorphous material
Crystalline material
None of these
Which of the following is not the correct method of increasing fatigue limit?
Shot peening
Nitriding of surface
Cold working
Surface decarburisation
In a hardening process, the hypo-eutectoid steel is
Heated from 30°C to 50°C above the upper critical temperature and then cooled in still air
Heated from 30°C to 50°C above the upper critical temperature and then cooled suddenly in a suitable cooling medium
Heated from 30°C to 50°C above the upper critical temperature and then cooled slowly in the furnace
Heated below or closes to the lower critical temperature and then cooled slowly
Nodular cast iron is produced by adding ________ to the molten cast iron.
Nickel
Chromium
Copper
Magnesium
Cartridge brass can be
Cold rolled into sheets
Drawn into wires
Formed into tube
Any one of these
Cast iron is characterised by minimum of following percentage of carbon
0.2 %
0.8 %
1.3 %
2 %
Manganese in steel increases its
Tensile strength
Hardness
Ductility
Fluidity
Gamma iron exits at following temperature
Room temperature
Near melting point
Between 1400°C and 1539°C
Between 910°C and 1400°C
Gamma-iron occurs between the temperature ranges of
400°C to 600°C
600°C to 900°C
900°C to 1400°C
1400°C to 1530°C
Nodular iron has
High machinability
Low melting point
High tensile strength
All of the above
Slow plastic deformation of metals under a constant stress is known as
Creep
Fatigue
Endurance
Plastic deformation
Cold rolled steel sheets contain carbon of the following order
0.1 %
0.2 %
0.4 %
0.6 %
Basic constituents of Monel metal are
Nickel, copper
Nickel, molybdenum
Zinc, tin, lead
Nickel, lead and tin
The presence of sulphur in pig iron makes
It easily machinable
It brittle
It hard
The casting unsound
The property of a material which enables it to retain the deformation permanently, is called
Brittleness
Ductility
Malleability
Plasticity
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
Eutectoid reaction occurs at
600°C
723°C
1147°C
1493°C
The steel widely used for motor car crankshafts is
Nickel steel
Chrome steel
Nickel-chrome steel
Silicon steel
Machining properties of steel are improved by adding
Sulphur, lead, phosphorous
Silicon, aluminium, titanium
Vanadium, aluminium
Chromium, nickel
For a steel containing 0.8% carbon
There is no critical point
There is only one critical point
There are two critical points
There can be any number of critical points
Chromium when added to steel __________ the tensile strength.
Does not effect
Decreases
Increases
None of these
Maximum percentage of carbon in austenite is
0.025 %
0.26 %
0.8 %
1.7 %
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