Chapter 5 Review of Physical Metallurgy

Question 1

1. Copper is a very useful non-ferrous metal. It has significant advantages because of certain critical properties. Which of the following would be a significant property for copper?

a. Has low thermal conductivity and is useful in alloying with aluminum to increase its use in cold storage vessels.
b. Has high electrical conductivity and it very useful for conductors in major electricity transmission
c. Is very easy to weld due to its low thermal conductivity
d. Its light weight makes it usable for structural components in high-speed trains

Answer 1

b. Has high electrical conductivity and it very useful for conductors in major electricity transmission

Question 2

2. Most metals do not exist in the earth in their elemental form. They are usually combined with other elements in an ore and must be smelted in order to separate the metal from its ore. What are the most common elements metals are combined with prior to smelting?

a. Carbonates and nitrides
b. Nitrides and hydrides
c. Oxides and sulphides
d. Hydrides and chlorides

Answer 2

c. Oxides and sulphides

Question 3

3. The blast furnace contains a series of pipes called “tuyeres” in its lower section. What are these ’tuyeres” used for?

a. For blowing in vaporized limestone
b. They provide the pathway for the entrance of iron ore pellets
c. They provide entry for oxygen gas
d. They provide entry for hot air.

Answer 3

d. They provide entry for hot air.

Question 4

4. The basic oxygen furnace makes use of what property to assist in removing impurities from the melt (e.g. phosphorous)?

a. Oxygen at low temperatures
b. Hot air which can generally gas off the impurities
c. A refractory lining of basic material
d. A lining of silicon brick in the furnace

Answer 4

c. A refractory lining of basic material

Question 5

5. There are several types, grades and quality of steel. How can a “killed” steel be defined?

a. If the cooling sequence after casting is too severe, a killed steel results
b. Killed steels are fully deoxidized, normally with silicon and aluminum, and no gas evolution occurs.
c. Killed steels are characterized by variable degrees of uniformity in composition, intermediate between a reduced level of oxidation inoculation and rimmed steels
d. Killing a steel is to increase the carbon content so that the final composition is close to “cast iron”

Answer 5

b. Killed steels are fully deoxidized, normally with silicon and aluminum, and no gas evolution occurs.

Question 6

6. Iron can change its crystallographic form as temperature changes. What form does iron take at a temperature of 250 degrees celsius?

a. The body-centered cubic ferrite lattice form
b. The face-centered cubic, austenite lattice form
c. The clo5e-packed hexagonal delta lattice form
d. The distorted lattice form known as pearlite.

Answer 6

a. The body-centered cubic ferrite lattice form

Question 7

7. Which one of the unique crystallographic structures of iron can dissolve a lot of an element
   critical to the properties of steel?

a. The face centered cubic lattice can dissolve up to 1.7% carbon
b. The body centered cubic lattice can dissolve up to 1.7% carbon
c. The face centered cubic lattice can dissolve up to 1.7% cementite
d. The face centered cubic lattice can dissolve up to 1.7% pearlite

Answer 7

a. The face centered cubic lattice can dissolve up to 1.7% carbon

Question 8

8. What is the makeup of the microstructural component known as pearlite?

a. Pearlite is a layered structure of austenite and cementlte
b. Pearlite is always a mixture of austenite and ferrite
c. Pearlite is another name for graphite and it is distributed as flakes in the microstructure
d. Pearlite can be a layered structure of cementite and ferrite

Answer 8

d. Pearlite can be a layered structure of cementite and ferrite

Question 9

9. If a steel had been rolled in only one direction, which of the following would be pertinent in regard to the steel’s ductility?

a. Ductility will be greatest in the rolling direction
b. Ductility will be greatest in the through thickness direction
c. Ductility will be equal in the rolling and transverse direction
d. Ductility will be greatest in the direction transverse to the rolling direction

Answer 9

a. Ductility will be greatest in the rolling direction

Question 10

10. In basic carbon steels, many microstructures can be formed by the process of heating and cooling as in annealing or welding. Of these microstructures, which would be the hardest?

a. A mixture of fine pearlite and course pearlite
b. A fully pearlitic structure
c. A mixture of cementite and ferrite
d. A fully martensitic structure

Answer 10

d. A fully martensitic structure

Question 11

11. When quenching a steel from the austenite range, it’s possible to get a microstructure of martensite. What may be the properties of this martensitic structure?

a. The microstructure leads to high strength with great toughness
b. The microstructure leads to high strength but lacks toughness
c. The microstructure has great corrosion properties
d. Martensitic microstructures lead to great strength and great ductility

Answer 11

b. The microstructure leads to high strength but lacks toughness

Question 12

12. Steel can be strengthened in many ways, but there is only one approach that will increase both strength and toughness. Which of the following methods will achieve this?

a. Precipitation hardening and over aging
b. Substitutional solid solution strengthening
c. Quenching and low-temperature tempering
d. Increasing the number of grain boundaries by grain refinement

Answer 12

d. Increasing the number of grain boundaries by grain refinement

Question 13

13. What kind of carbon content would one expect in a specification that covers chemistries for
    cold chisels and band saws?

a. The carbon will be more than 1.7%
b. The carbon will in the range 0.50 to 0.80%
c. The carbon will be in the range .0.03 to 0.08%
d. The carbon will be in the range 1.2% to 1.4%

Answer 13

b. The carbon will in the range 0.50 to 0.80%

Question 14

14. By adding a prescribed amount of copper to an HSLA steel, the following additional benefits can occur?

a. Allows the steel to be joined using copper electrodes
b. Makes hardening of the steel much easier
c. Atmospheric corrosion resistance is improved
d. Electrical resistance is improved

Answer 14

c. Atmospheric corrosion resistance is improved

Question 15

15. Grain size can influence the properties of steel in significant ways. Which heat treatment is usually selected to improve a steels toughness?

a. Normalizing reduces grain size to increase toughness
b. Annealing reduces grain size to increase toughness
c. Quenching and then cold working increases the grain size to increase toughness
d. Tempering reduces the martensitic grain size to improve toughness.

Answer 15

a. Normalizing reduces grain size to increase toughness

Question 16

16. Changing the quantity of what element in steel had greatly reduced the incidence of lamellar tearing in the modern steelmaking era?

a. Decreasing the calcium content
b. Increasing the grain refining element niobium
C. Increasing manganese content
d. Decreasing sulphur content

Answer 16

d. Decreasing sulphur content

Question 17

17. When pure iron begins to freeze slowly, it goes through changes in the atomic lattice from a temperature of 1536 deg C down to zero. What are these changes?

a. From austenite to ferrite and back to austenite
b. From BCC to FCC and back to BCC
c. From CPH to FCC to BCC
d. From ferrite to pearlite and then to austenite.

Answer 17

b. From BCC to FCC and back to BCC

Question 18

18. Since BCC iron dissolves very little carbon, most of the carbon in a steel, below 723 C is rejected from the BCC ferrite and will be present in the form of?

a. A pure carbon compound known as alpha graphite
b. A carbonate which is chemically is combined with oxygen in the solidifying steel
c. An iron carbide in which carbon is chemically combined and known as cementite
d. Pearlite, where the carbon is spread equally between ferrite and pure carbon in a lath structure.

Answer 18

c. An iron carbide in which carbon is chemically combined and known as cementite

Question 19

19. When a steel is heated to a temperature to cause the structure to transform to austenite, new grains must grow in a process called recrystallization. What may be the result of the temperature of recrystallization if allowed to rise?

a. Grain growth will occur and eventually perlite will be formed in a course form.
b. Grain growth will occur and on cooling the toughness of the steel will be significantly increased.
c. Grain growth will be retarded resulting in the best strength and toughness on cooling to the ferrite range.
d. Grain growth will occur and, on cooling the toughness of the steel will be reduced.

Answer 19

d. Grain growth will occur and, on cooling the toughness of the steel will be reduced.

Question 20

20. A form of solidification cracking called hot shortness can occur when steels are deformed at high temperature. What can cause this?

a. High sulphur content and usually in steels designed to be machined
b. High manganese content and usually in steels designed to be forged
c. High sulphur content and usually in steels designed to be welded by high energy radiation
d. High calcium content and usually in steels designed to be centrifugally cast

Answer 20

a. High sulphur content and usually in steels designed to be machined

Question 21

21. When a steel bar is continually loaded in tension, a certain behaviour is exhibited. This behaviour is described as follows?

a. The steel bar deforms plastically and continues to deform until it fractures.
b. Initially, the steel bar deforms elastically and continues to deform until it yields and then deforms plastically.
C. The steel bar deforms in a continuous elastic spectrum without yielding.
d. The steel bar deforms elastically and continues to deform until it yields and then fractures with zero elongation.

Answer 21

b. Initially, the steel bar deforms elastically and continues to deform until it yields and then deforms plastically.

Question 22

22. Chromium is a useful non-ferrous metal for alloying and it has significant advantages because of certain properties. Which of the following would be a significant property for this material?

a. Its light and used in aircraft alloys
b. It increases corrosion resistance and hardness
c. It softens a steel when alloyed with it
d. It increases the electrical conductivity when added to steel in micro amounts.

Answer 22

b. It increases corrosion resistance and hardness

Question 23

23. Cold forming has certain advantages over other forming methods. Which of the following is an advantage of the cold forming method?

a. Cold forming results in cells formation which improves dislocation density
b. Cold forming gives a good finish and close dimensional tolerances
c. Cold working softens the material, allowing further working or forming
d. Cold working will give significant improvements in ductility

Answer 23

b. Cold forming gives a good finish and close dimensional tolerances

Question 24

24. There are several heat treatment approaches to change the properties of a particular steel. One of these is annealing. What advantage can annealing give?

a. To harden the steel and lower its residual stress content
b. To soften the steel and improve its toughness
c. To soften the steel and improve machinability
d. To soften the steel and improve its weldability

Answer 24

c. To soften the steel and improve machinability

Question 25

25. A thermal stress relief treatment is often specified for welded fabrications for several reasons. Which of the following applies to stress relief

a. A stress relief treatment is carried out above the metallurgical transformation temperature and will cause some changes in the metallurgical structure.
b. Stress relief improves dimensional stability during machining,
c. Stress relief to reduces grain size and thus increases fracture toughness.
d. Stress relief causes tempering of the cementite/ferrite lath structure known as pearlite.

Answer 25

b. Stress relief improves dimensional stability during machining.

Question 26

26. There is a major group of low alloy steels intended for various structural applications and have higher yield strengths than regular carbon steels. What are these steels generally known as?

a. Super strength low alloy steels or SSLA steels
b. High strength medium alloy steels or MSLA steels
c. High strength heat treatable steels or HSHT steels
d. High-strength low alloy steels, or HSLA steels.

Answer 26

d. High-strength low alloy steels, or HSLA steels.

Question 27

27. How can the structure of martensite be improved to increase its toughness but maintain the significant strength of the steel?

a. By normalizing at a temperature below the recry5tallization temperature
b. By a simple stress relief followed by a second post-stress relief hold at low temperatures
c. By tempering the martensite in the austenitic range followed by a slow, controlled cool
d. By tempering the martensite at temperatures where no changes take place in the crystal structure

Answer 27

d. By tempering the martensite at temperatures where no changes take place in the crystal structure

Question 28

28. Which microstructure in the phase diagram of carbon steel would exhibit complete dissolution of carbon?

a. Ferrite
b. Pearlite
c. Cementite
d. Austenite

Answer 28

b. Pearlite

Question 29

29. Fine grain steel versus coarse grain steel heated at a range of 800 to 1000 C would exhibit ________________________

a. the same grain sizes
b. coarse grain steel exhibits more grain boundaries
c. fine grain steel exhibits less grain boundaries
d. fine grain steel would exhibit small grain sizes

Answer 29

a. the same grain sizes

Question 30

30. When force is applied to a bar, plastic deformation may occur. This phenomenon is called slip, and this is because of dislocation. Dislocation is:

a. local distortion that occurs at atomic level as the atoms try to fit the proper pattern
b. distortion only at the level of grain boundaries
C. when atoms lose electrons
d. increased elasticity of a metal

Answer 30

b. distortion only at the level of grain boundaries