Grey 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 is obtained by cooling rapidly. It is almost unmachinable
Is produced by annealing process. I is soft, tough and easily machined metal
Is produced by small additions o magnesium (or cerium) in the ladle Graphite is in nodular or spheroidal form and is well dispersed throughout the material
Correct Answer :
A. Contains 1.7 to 3.5% carbon in Free State and is obtained by the slow cooling of molten cast iron
Related Questions
Which of the following represents the allotropic forms of iron?
Alpha iron, beta iron and gamma iron
Alpha iron and beta iron
Body centred cubic iron and face centred cubic iron
Alpha iron, gamma from and delta iron
Balls for ball bearings are made of
Cast iron
Mild steel
Stainless steel
Carbonchrome steel
The elastic stress strain behaviour of rubber is
Linear
Nonlinear
Plastic
No fixed relationship
Foundry crucible is made of
Mild steel
German silver
Lead
Graphite
Compressive strength of grey cast iron in tonnes/cm is of the order of
35
57
710
1015
Malleability 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
The hardness is the property of a material due to which it
Can be drawn into wires
Breaks with little permanent distortion
Can cut another metal
Can be rolled or hammered into thin sheets
The material widely used for making pendulums of clocks is
Stainless steel
High speed steel
Heat resisting steel
Nickel steel
Which of the following constituents of steels is softest and least strong?
Austenite
Pearlite
Ferrite
Cementite
When steel containing less than 0.8% carbon is cooled slowly from temperatures above or within the critical range, it consists of
Mainly ferrite
Mainly pearlite
Ferrite and pearlite
Pearlite and cementite
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
Free carbon in iron makes the metal
Soft and gives a 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
Blast furnace is used to produce
Pig iron
Cast iron
Wrought iron
Steel
The alloying element which reduces the formation of iron sulphide in steel is
Chromium
Nickel
Vanadium
Manganese
Hardness of lower bainite (tempered martensite) is about
RC 65
RC 48
RC 57
RC 80
Dow metal contains
94% aluminium, 4% copper and 0.5% Mn, Mg, Si and Fe
92.5% aluminium and, 4% copper, 2% nickel and 1.5% Mg
90% aluminium and 90% copper
90% magnesium and 9% aluminium with some copper
Duralumin 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
Gun metal contains
70% copper and 30% zinc
90% copper and 10% tin
85 - 92% copper and rest tin with little lead and nickel
70 - 78% copper and rest tin
Nodular cast iron is produced by adding ________ to the molten cast iron.
Nickel
Chromium
Copper
Magnesium
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
Which of the following impurity in cast iron makes it hard and brittle?
Silicon
Sulphur
Manganese
Phosphorus
Steel made from phosphate iron is
Brittle
Hard
Ductile
Tough
Hematite iron ore contains iron about
30 %
45 %
55 %
70 %
Wrought iron is
Hard
High in strength
Highly resistant to corrosion
Heat treated to change its properties
The hardness of steel increases if it contains
Austenite
Martensite
Pearlite
Cementite
The presence of hydrogen in steel causes
Reduced neutron absorption cross-section
Improved Weldability
Embrittlement
Corrosion resistance
Connecting rod is, usually, made from
Low carbon steel
High carbon steel
Medium carbon steel
High speed steel
The ultimate tensile strength and yield strength of most of the metals, when temperature falls from 0 to 100°C will
Increase
Decrease
Remain same
First increase and then decrease
The percentage of carbon in low carbon steel is
0.05 %
0.15 %
0.3 %
0.5 %
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