1. For binary phase diagram Gibbs phase rule may be given as ____________
a) F = C + P + 2
b) F = C – P + 2
c) F = C – P + 1
d) F = C + P – 1
Explanation: Binary phase diagrams has two components. Apart from temperature and pressure, we will be having one composition variable for each of the phases in equilibrium. In order to simplify the Gibbs phase rule on paper (in 2D), binary phase diagrams are usually drawn at atmospheric pressure, showing variations in temperature and composition only. Pressure changes often produce no significant effect on the equilibrium and, therefore, it is customary to ignore the pressure variable and the vapour phase. The modified condensed rule is represented as:
F = C – P + 1
2. The Line joining a liquid phase with liquid and solid phase mixture is known as ____________
a) Liquidus
b) Solidus
c) Tie line
d) Solvus
Explanation: Liquidus is the line joining liquid phase with liquid and solid phase mixture.
3. The line joining a solid phase with liquid and solid phase mixture is known as ____________
a) Liquidus
b) Solidus
c) Tie line
d) Solvus
Explanation: Solidus is the line joining liquid phase with liquid and solid phase mixture.
4. Melting point of copper (in oC) is?
a) 985
b) 1085
c) 1453
d) 1200
Explanation: The copper has a melting point of 1085oC.
5. Pig iron is a product of ____________
a) Cupola
b) Bessemer converter
c) Open hearth furnace
d) Blast furnace
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.
6. Cast iron is a product of ___________
a) Cupola
b) Bessemer converter
c) Open hearth furnace
d) Blast furnace
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.
7. Wrought iron is a product of ___________
a) Cupola
b) Bessemer converter
c) Puddling furnace
d) Blast furnace
Explanation: The puddling furnace creates wrought iron (nearly pure iron) from the pig iron. The wrought iron is tougher and malleable.
8. Steel is a product of ___________
a) Cupola
b) Bessemer converter
c) Puddling furnace
d) Blast furnace
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.
9. Red hardness of an alloy steel can be improved by adding ____________
a) Tungsten
b) Vanadium
c) Manganese
d) Titanium
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.
10. Abrasion resistance of an alloy steel can be improved by adding ___________
a) Tungsten
b) Vanadium
c) Manganese
d) Chromium
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.