Machining properties of steel are improved by adding
Sulphur, lead, phosphorous
Silicon, aluminium, titanium
Vanadium, aluminium
Chromium, nickel
Correct Answer :
A. Sulphur, lead, phosphorous
Related Questions
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
Melting point of iron is
1539°C
1601°C
1489°C
1712°C
The hardness of steel increases if it contains
Pearlite
Ferrite
Cementite
Martensite
Taps dies and drills contain carbon
Below 0.5 %
Below 1 %
Above 1 %
Above 2.2 %
Blast furnace is used to produce
Pig iron
Cast iron
Wrought iron
Steel
Malleable 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 and is obtained by cooling rapidly. It is almost unmachinable
Is produced by annealing process. It is soft, tough, and easily machined metal
Is produced by small additions of magnesium (or cerium) in the ladle. Graphite is in the nodular or spheroidal form and is well dispersed throughout the material
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
Which of the following impurity in cast iron makes it hard and brittle?
Silicon
Sulphur
Manganese
Phosphorus
The metallic structure of mild steel is
Body centred cubic
Face centred cubic
Hexagonal close packed
Cubic structure
The most effective inhibitor of grain growth, when added in small quantities is
Carbon
Vanadium
Manganese
Cobalt
German silver contains
1% silver
2.5% silver
5% silver
10% silver
The main alloying elements high speed steel in order of increasing proportion are
Vanadium, chromium, tungsten
Tungsten, titanium, vanadium
Chromium, titanium, vanadium
Tungsten, chromium, titanium
In full annealing, the hypo eutectoid steel is heated from 30°C to 50°C above the upper critical temperature and then cooled
In still air
Slowly in the furnace
Suddenly in a suitable cooling medium
Any one of these
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
Hardness of lower bainite (tempered martensite) is about
RC 65
RC 48
RC 57
RC 80
Nodular cast iron is produced by adding ________ to the molten cast iron.
Nickel
Chromium
Copper
Magnesium
In nodular iron, graphite is in the form of
Cementite
Free carbon
Flakes
Spheroids
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
Sulphur in steel
Acts as deoxidiser
Reduces the grain size
Decreases tensile strength and hardness
Lowers the toughness and transverse ductility
The material widely used for making pendulums of clocks is
Stainless steel
High speed steel
Heat resisting steel
Nickel steel
In mottled cast iron, carbon is available in
Free form
Combined form
Nodular form
Partly in free and partly in combined state
Which of the following iron exist between 910°C and 1403°C?
α-iron
β-iron
γ-iron
δ-iron
Which of the following property is desirable in parts subjected to shock and impact loads?
Strength
Stiffness
Brittleness
Toughness
Delta-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
Ductile 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 and is obtained by cooling rapidly. It is almost unmachinable
Is produced by annealing process. It is soft, tough and easily machined metal
Is produced by small additions of magnesium (or creium) in the ladle. Graphite is in nodular or spheroidal form and is well dispersed throughout the material
The stiffness is the ability of a material to resist
Deformation under stress
Fracture due to high impact loads
Externally applied forces with breakdown or yielding
None of the above
Foundry crucible is made of
Mild steel
German silver
Lead
Graphite
The ability of a material to resist fracture due to high impact loads, is called
Strength
Stiffness
Toughness
Brittleness
Vanadium in high speed steels
Promotes decarburisation
Provides high hot hardness
Forms very hard carbides and thus increases wear resistance
Promotes retention of austenite
Eutectoid steel contains following percentage of carbon
0.02 %
0.3 %
0.63 %
0.8 %