This set of Manufacturing Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Ferrous Metal”.
1. Pig iron is a product of ____________
a) Cupola
b) Bessemer converter
c) Open hearth furnace
d) Blast furnace
Answer: d
Explanation: Blast furnace when smelted iron ore in it, produces pig iron. Pig iron has a carbon content, typically 3.5-4.5%, which makes it brittle, thus of less industrial use.
2. Cast iron is a product of ___________
a) Cupola
b) Bessemer converter
c) Open hearth furnace
d) Blast furnace
Answer: a
Explanation: The cupola furnace (a modified blast furnace) can be used to melt cast irons, bronzes, etc. Cast irons have a carbon content of 2-4%, and have low melting temperatures, which makes them easily castable.
3. Wrought iron is a product of ___________
a) Cupola
b) Bessemer converter
c) Puddling furnace
d) Blast furnace
Answer: c
Explanation: The puddling furnace creates wrought iron (nearly pure iron) from the pig iron. The wrought iron is tougher and malleable.
4. Steel is a product of ___________
a) Cupola
b) Blast furnace
c) Puddling furnace
d) Bessemer converter
Answer: d
Explanation: The Bessemer converter was the first inexpensive furnace to make steel in olden days. The fundamental idea is, removal of impurities from iron and making steel by oxidizing. Open hearth furnace has taken over Bessemer process due to its nitrogen control in steel.
5. Red hardness of an alloy steel can be improved by adding ____________
a) Tungsten
b) Vanadium
c) Manganese
d) Titanium
Answer: a
Explanation: Red hardness means capability of material to retain hardness at high temperature. It can be achieved for steel when alloyed high high melting metals like, tungsten, molybdenum, vanadium and chromium, etc.
6. Abrasion resistance of an alloy steel can be improved by adding ___________
a) Tungsten
b) Vanadium
c) Manganese
d) Chromium
Answer: d
Explanation: Chromium is generally added to steel to increase corrosion resistance and oxidation, to increase hardenability, to improve high-temperature strength, and to improve abrasion resistance in high-carbon compositions. The formation of hexagonal Cr7C3 is responsible for this abrasion resistance to steel.
7. Wear resistance of an alloy steel can be improved by adding ___________
a) Tungsten
b) Vanadium
c) Manganese
d) Titanium
Answer: c
Explanation: Manganese is normally present in all commercial steels. High levels of manganese presence produces an austenitic steel with improved wear and abrasion resistance.
8. Corrosion resistance of an alloy steel can be improved by adding ___________
a) Tungsten
b) Vanadium
c) Chromium
d) Titanium
Answer: c
Explanation: Chromium when added in the range 10.5%-18% in weight to steel, forms a passive oxide layer (Cr2O3), thus transforming steel to a corrosion resistant steel (stainless steel).
9. Tensile strength of an alloy steel can be improved by adding ____________
a) Nickel
b) Vanadium
c) Manganese
d) Titanium
Answer: a
Explanation: Nickel can improve tensile strength as well as toughness of alloy steel. Small additions of niobium (Nb) also increases the tensile strength of carbon steel.
10. Which of the following induces fine grain distribution in alloy steel?
a) Nickel
b) Vanadium
c) Manganese
d) Titanium
Answer: b
Explanation: After Al, vanadium if by far the mostly used grain refiner in steel. It forms a microscopic precipitate particle in steel, which acts as pinning agents, thus obstruct the grain growth at higher temperatures, encouraging new grains to nucleate.