Manganese is added in low carbon steel to
Make the steel tougher and harder
Raise the yield point
Make the steel ductile and of good bending qualities
All of the above
Correct Answer :
C. Make the steel ductile and of good bending qualities
Related Questions
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
According to Indian standard specifications, plain carbon steel designated by 40 C8 means that the carbon content is
0.04 %
0.35 to 0.45 %
0.4 to 0.6 %
0.6 to 0.8 %
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
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
Which of the following display properties similar to that of steel?
Blackheart cast iron
White-heart cast iron
Both (A) and (B)
None of these
Steel containing ferrite and pearlite is
Hard
Soft
Tough
Hard and tough
Tungsten when added to steel ________ the critical temperature.
Does not effect
Lowers
Raises
None of these
The strength is the ability of a material to resist
Deformation under stress
Externally applied forces with breakdown or yielding
Fracture due to high impact loads
None of these
The elastic stress strain behaviour of rubber is
Linear
Nonlinear
Plastic
No fixed relationship
The presence of sulphur in pig iron makes
It easily machinable
It brittle
It hard
The casting unsound
A material is known as allotropic or polymorphic if it
Has a fixed structure under all conditions
Exists in several crystal forms at different temperatures
Responds to heat treatment
Has its atoms distributed in a random pattern
Which of the following iron exist between 910°C and 1403°C?
α-iron
β-iron
γ-iron
δ-iron
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
Which of the following is not the correct method of increasing fatigue limit?
Shot peening
Nitriding of surface
Cold working
Surface decarburisation
Which is false statement about tempering? Tempering is done to
Improve machinability
Improve ductility
Improve toughness
Release stresses
Sulphur in steel
Acts as deoxidiser
Reduces the grain size
Decreases tensile strength and hardness
Lowers the toughness and transverse ductility
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
Cast iron is manufactured in
Blast furnace
Cupola
Open hearth furnace
Bessemer converter
Which of the following has highest specific strength of all structural materials?
Magnesium alloys
Titanium alloys
Chromium alloys
Magnetic steel alloys
Aluminium bronze contains
94% aluminium, 4% copper and 0.5% Mn, Mg, Si and Fe
92.5% aluminium, 4% copper, 2% nickel, and 1.5% Mg
10% aluminium and 90% copper
90% magnesium and 9% aluminium with some copper
The hardness of steel increases if it contains
Pearlite
Ferrite
Cementite
Martensite
Which is false statement about properties of aluminium?
Modulus of elasticity is fairly low
Wear resistance is very good
Fatigue strength is not high
Creep strength limits its use to fairly low temperatures
Corundum contains more than 95%
Steel
Al2O3
SiO2
MgO
The following element can't impart high strength at elevated temperature
Manganese
Magnesium
Nickel
Silicon
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
The lower critical point for all steels is
600°C
700°C
723°C
913°C
Points of arrest for iron correspond to
Stages at which allotropic forms change
Stages at which further heating does not increase temperature for some time
Stages at which properties do not change with increase in temperature
There is nothing like points of arrest
Which of the following constituents of steels is softest and least strong?
Austenite
Pearlite
Ferrite
Cementite
Addition of lead and bismuth to aluminium results in
Improvement of casting characteristics
Improvement of corrosion resistance
One of the best known age and precipitation hardening systems
Improving machinability
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