1. Steel is mainly an alloy of
a) Iron and Carbon
b) Sulphur and Zinc
c) Zinc and tin
d) Phosphorous and Tin
Discussion
Explanation: Steel is alloy of iron and carbon. Apart from carbon, a small percent of manganese, sulphur, phosphorous, chrome, nickel, and copper are added to give special properties to steel.
2. Which of the following is a disadvantage of Steel?
a) High strength per unit mass
b) High durability
c) Fire and corrosion resistance
d) Reusable
Discussion
Explanation: Steel has high strength per unit mass, highly durable, and is reusable. But steel is poor in fire and corrosion resistance, it needs to be protected.
3. Elastic Modulus of Steel is __________
a) 1.5 x 109 N/mm2
b) 2.0 x 105 N/mm2
c) 2.0 x 105 N/m2
d) 1.5 x 109 N/m2
Discussion
Explanation: Elastic modulus = Stress/Strain. As per IS 800-2007, elastic modulus of steel is 2.0 x 10⁵ N/mm².
4. Unit mass of Steel = ________
a) 785 kg/m3
b) 450 kg/m3
c) 450 kg/cm3
d) 7850 kg/m3
Discussion
Explanation: As per IS 800-2007, unit mass of steel is 7850 kg/m³. A steel member with small section which has little self-weight is able to resist heavy loads because steel members have high strength per unit weight.
5. Poisson’s ratio of steel is ________
a) 0.1
b) 1.0
c) 0.3
d) 2.0
Discussion
Explanation: Poisson’s ratio = transverse strain/axial strain. As per IS 800-2007, Poisson’s ratio of steel is 0.3 in elastic range and it is 0.5 in plastic range.
6. Structural Steel normally has carbon content less than _______
a) 1.0%
b) 0.6%
c) 3.0%
d) 5.0%
Discussion
Explanation: Structural Steel normally have a carbon content less than 0.6%. Carbon content increases hardness, yield and tensile strength of steel but it decreases ductility and toughness.
7. What is the permissible percentage of Sulphur and Phosphorous content in steel?
a) 0.1%, 0.12%
b) 1.0%, 3.0%
c) 3.0%, 1.0%
d) 1.0%, 1.0%
Discussion
Explanation: Sulphur content is generally between 0.02 – 0.1%. If more than 0.1%, it decreases strength and ductility of steel. If Phosphorous is more than 0.12%, it reduces shock resistance, ductility and strength of steel.
8. What happens when Manganese is added to steel?
a) decreases strength and hardness of steel
b) improves corrosion resistance
c) decreases ductility
d) improves strength and hardness of steel
Discussion
Explanation: Manganese is added to improve strength and hardness of steel . Based on Manganese content, steel are classified as Carbon Manganese steel (Mn >1%) and Carbon Steel (Mn <1%). If its content exceeds 1.5%, it increases the formation of martensite and hence decreases ductility and toughness.
9. Which of the following is the effect of increased content of Sulphur and Phosphorous in Steel ?
a) yields high strength
b) affects weldability
c) increases resistance to corrosion
d) improves resistance to high temperature
Discussion
Explanation: When sulphur and phosphorous is used beyond 0.06%, it imparts brittleness and affects weldability and fatigue strength.
10. Which of the following is added to steel to increase resistance to corrosion?
a) Carbon
b) Manganese
c) Sulphur
d) Copper
Discussion
Explanation: Addition of small quantity of copper increases resistance to corrosion. Even Chrome and Nickel are added to impart corrosion resistance property to steel