Casting, Forming and Welding Multiple Choice Questions & Answers (MCQs) on “Open Hearth Surface”.
1. The impurities are burnt from which material in an open hearth furnace to produce steel?
a) Cast iron
b) Gray iron
c) Pig iron
d) Copper
Answer: c
Clarification: The materials such as high carbon content or other impurities which are present inside the pig iron are burnt in order to obtain steel.
2. Open hearth process did not allow the steel to be in contact with which gas?
a) Nitrogen
b) Helium
c) Carbon dioxide
d) Neon
Answer: a
Clarification: The contact of steel with the nitrogen gas causes the steel to become brittle. This was one of the difficulties which was later overcome by open hearth furnace.
3. What is the minimum capacity of an open hearth furnace in steel foundries?
a) 5 tons
b) 4 tons
c) 6 tons
d) 3 tons
Answer: a
Clarification: Open hearth process was primarily used only for steel making, it was later brought to use in steel foundries. The minimum capacity of open hearth furnace in steel foundries is 5 tons.
4. Which of the following is not charged in the open hearth furnace?
a) Scrap metal
b) Flux
c) Pig iron
d) White iron
Answer: d
Clarification: In an open hearth furnace, the scrap metal, flux and the pig iron are charged through the charging doors. But, white iron is not charged into the open hearth furnace.
5. What is the maximum capacity of an open hearth furnace in steel foundries?
a) 250 tons
b) 100 tons
c) 160 tons
d) 130 tons
Answer: b
Clarification: None.
6. Which material is applied to the hearth if the process is acidic?
a) Silica
b) Dolomite
c) Silicon monoxide
d) Xenon di fluoride
Answer: a
Clarification: In an open hearth furnace, there is a large basin which is called as hearth furnace. If the operation is going to be acidic, there is a lining of silica provided to the hearth.
7. Which of the following is not used as a fuel in an open hearth furnace?
a) Atomised oil
b) Natural gas
c) Peat
d) Producer gas
Answer: c
Clarification: Only gaseous fuels are used for the burning process in an open hearth furnace. Peat is a very basic form of coal and cannot be used as a fuel here.
8. Open hearth furnace is a faster operation process than oxygen furnace.
a) True
b) False
Answer: b
Clarification: The open hearth furnace had this as one of its limitations, that the process was time consuming. It took more time than basic oxygen furnace and electric arc furnace.
9. Which material is applied to the hearth if the process is basic?
a) Silica
b) Dolomite
c) Silicon monoxide
d) Xenon di fluoride
Answer: b
Clarification: None.
10. Only acid lined furnace depend on type of steel to be produced?
a) True
b) False
Answer: b
Clarification: Acid lined furnace and basic lined furnace in the hearth depend upon the type of steel to be manufactured and the type of metal charge.