The hardness of steel increases if it contains
Austenite
Martensite
Pearlite
Cementite
Correct Answer :
B. Martensite
Related Questions
The alloying element which reduces the formation of iron sulphide in steel is
Chromium
Nickel
Vanadium
Manganese
Smelting is the process of
Removing the impurities like clay, sand etc. from the iron ore by washing with water
Expelling moisture, carbon dioxide, sulphur and arsenic from the iron ore by heating in shallow kilns
Reducing the ore with carbon in the presence of a flux
All of the above
An alloy steel which is work hardenable and which is used to make the blades of bulldozers, bucket wheel excavators and other earth moving equipment contain iron, carbon and
Chromium
Silicon
Manganese
Magnesium
The charge is fed into the blast furnace through the
Stack
Throat
Bosh
Tyres
Vanadium in high speed steels
Promotes decarburisation
Provides high hot hardness
Forms very hard carbides and thus increases wear resistance
Promotes retention of austenite
The most effective inhibitor of grain growth, when added in small quantities is
Carbon
Vanadium
Manganese
Cobalt
Cupola produces following material
Cast iron
Pig iron
Wrought iron
Malleable iron
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 alloy used for making electrical resistances and heating elements is
Nichrome
Invar
Magnin
Elinvar
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
According to Indian standard specifications, SG 400/15 means
Spheroidal graphite cast iron with B.H.N. 400 and minimum tensile strength 15 MPa
Spheroidal graphite cast iron with minimum tensile strength 400 MPa and 15 percent elongation
Spheroidal graphite cast iron with minimum compressive strength 400 MPa and 15 percent reduction in area
None of the above
Nickel when added to copper improves
Machinability
Hardness
Hardness and strength
Strength and ductility
The type of space lattice found in gamma-iron is
Face centered cubic space lattice
Body centered cubic space lattice
Close packed hexagonal space lattice
None of these
The blade of a power saw is made of
Boron steel
High speed steel
Stainless steel
Malleable cast iron
Carbon steel is
Made by adding carbon in steel
Refined from cast iron
An alloy of iron and carbon with varying quantities of phosphorus and sulphur
Extensively used for making cutting tools
The ability of a material to absorb energy in the plastic range is called
Resilience
Creep
Fatigue strength
Toughness
Pick up the wrong statement Nickel and chromium in steel help in
Providing corrosion resistance
Improving machining properties
Providing high strength at elevated temperatures
Raising the elastic limit
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 crystal of alpha iron is
Body centered cubic
Face centered cubic
Hexagonal close packed
Cubic structure
Tin base white metals are used where the bearings are subjected to
Large surface wear
Elevated temperatures
Light load and pressure
High pressure and load
In malleable iron, carbon is present in the form of
Cementite
Free carbon
Flakes
Nodular aggregates of graphite
Free cutting steels
Are used where ease in machining is the criterion
Contain carbon in free form
Require least cutting force
Do not exist
Hardness of lower bainite (tempered martensite) is about
RC 65
RC 48
RC 57
RC 80
The property of a material which enables it to retain the deformation permanently, is called
Brittleness
Ductility
Malleability
Plasticity
Cyaniding is the process of
Dipping steel in cyanide bath
Reacting steel surface with cyanide salts
Adding carbon and nitrogen by heat treatment of steel to increase its surface hardness
Obtaining cyanide salts
Coarse grained steel
Is less tough and has a greater tendency to distort during heat treatment
Is more ductile and has a less tendency to distort during heat treatment
Is less tough and has a less tendency to distort during heat treatment
Is more ductile and has a greater tendency to distort during heat treatment
Iron-carbon alloys containing 1.7 to 4.3% carbon are known as
Eutectic cast irons
Hypoeutectic cast irons
Hypereutectic cast irons
None of these
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%
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
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