Metal 259
Exam 2 - Fall 2001

Only one answer per question. For a few questions, you may feel that more than one answer

1. What do Jominy curves measure?

a. w/o carbon
b. hardenability
c. austenitizing temperatures
d. quench severity
e. MAR start temperature

2. Which of the following is true for the composition ranges below:

a. A ­ hypereutectoid steels, B ­ hypoeuctectoid steels, C ­ cast irons
b. A ­ hypoeutectoid steels, B,C ­ hypereutectoid steels
c. A ­ proeutectoid FE can form, B ­ proeutectoid CM can form, C - cast irons
d. A ­ proeutectoid CM can form, B ­ proeutectoid FE can form, C ­ cast irons
e. A,B ­ proeutectoid FE can form, C ­ cast irons

3. Carbon in steels at equilibrium at room temperature can be found in these phases and/or microconstituents:

a. FE, P, CM
b. FE only
c. CM only
d. P only
e. FE, graphite

4. Which of the following is NOT a class of stainless steel?

a. pearlitic
b. martensitic
c. ferritic
d. austenitic

5. Phases present in a hypereutectoid steel slowly cooled from the AUS phase:

a. FE, P
b. CM, P
c. FE, CM
d. CM, graphite
e. AUS, P

6. A 9160 steel is very rapidly quenched to a temperature 20° below the ms (40° above the mf) and held at this temperature for a month. The phases present are:

a. AUS, FE, CM
b. AUS, MAR
c. AUS, Bainite
d. MAR, P
e. MAR, FE, CM

7. One way to increase hardenability is to add alloy elements; which of these alloying elements does not latch onto C atoms to effect this increase?

a. V
b. W
c. Cr
d. Mo
e. None of the above

8. Small sections of a large cast iron casting must be severely cold-worked after casting. Which of the following must be done:

a. the casting must be annealed before working
b. the casting must be quenched to obtain a predominantly CM structure ­ no graphite
c. the casting must be slowly cooled to avoid MAR formation
d. the molten metal must be inoculated with Mg

9. A major problem in the cold forming of austenitic stainless steels:

a. oxidation
b. chromium evaporation
c. work hardening
d. corrosion
e. extremely high hot working temperatures

10. Which of the following cannot be used for case hardening a 1020 steel:

a. nitriding
b. carbonitriding
c. gas carburizing
d. induction hardening
e. all of the above can be used

11. Which of the following will not form upon tempering a steel (the tempering time can vary):

a. AUS
b. transition Fe carbides
c. alloy carbides
d. FE
e. CM

12. Make a rough estimate of the fraction of pearlite present in a 1080 steel, cooled as shown below:

a. 0%
b. 25%
c. 50%
d. 75%
e. 100%

13. The hardness at 0.1" in from the surface of a 2" diam. of a 5140 steel bar quenched with a severity of 0.2 is (see diagrams at end of exam paper):

a. RC 42
b. RC 32
c. RC 33
d. RC 34
e. RC 57

14. Which of the following is a true statement:

a. AUS can be formed by appropriately heating any mixture of FE and CM
b. under equilibrium conditions, P can form at any temperature in the range 723° C down to room temperature (the reaction rate at lower temperatures would be extremely slow)
c. a martensitic steel must be tempered in order to form the austenite phase
d. tempering MAR for long periods at high tempering temperatures causes P to form
e. tempering MAR for long periods at high tempering temperatures causes proeutectoid FE to form

15. Estimate the strength of a 1020 steel heated treated so as to contain the equilibrium phases:

a. 40 ksi
b. 60 ksi
c. 80 ksi
d. 100 ksi
e. 120 ksi

16. AUS can not be formed by heating which of the following to a sufficiently high temperature.

a. MAR
b. P
c. hypereutectoid steels
d. a 3% C cast iron
e. pure CM

17. We discussed a number of occasions in which AUS can be found at temperatures below 723° C. Which of the following is not a reason this is so:

a. diffusion rates in solids are slow
b. tempering is a time dependent process
c. the transformation to MAR is temperature dependent
d. some alloying elements have extensive solubilities in g-Fe

18. P:

a. a phase in steels
b. usually a very fine structure containing plates of FE and CM
c. cannot form in cast irons
d. contains CM only
e. sometimes forms at AUS compositions of other than about 0.8% C in plain carbon steels

19. Loss of brittleness in fresh MAR at the beginning of tempering is a direct result of

a. the formation of AUS
b. use of the correct austenitization temperature
c. low hardenability
d. formation of alloy carbide particles
e. stress relief

20. WC tools are:

a. tool steels with sufficiently large amounts of tungsten and carbon in them to form WC upon heat treatment
b. formed upon carburization of a W-containing steel
c. formed by heating a mixture of WC and Co to a temperature high enough to melt the Co, which flows around the WC and holds it together when cooled
d. tool steels quenched by Water Cooling
e. formed by a process that makes extensive use of diffusion

21. When tempering martensite:

a. no atom movement is involved
b. the atoms of the alloy elements attract the carbon atoms
c. the Fe atoms of the alloy elements do not attract the C atoms
d. the carbon atoms aggregate to form large graphite areas in the steel

22. Which of the following does NOT control the position of the TTT curve?

a. alloy element content
b. %C
c. AUS grain size
d. heat treatment

23. Which of the following is not used as a quenching medium?

a. air
b. oil
c. water
d. brine
e. all of the above are used

24. Which is not a way to increase the hardenability of a steel:

a. increase carbon content
b. move TTT curves by decreasing the amount of alloying elements present
c. temper it first
d. increase the AUS grain size

25. The difference between grey and ductile cast irons:

a. MAR cannot be formed in ductile cast irons
b. the morphology of the graphite particles is different
c. the morphology of the CM particles is different
d. in grey cast irons, all the carbon is present as CM, whereas, in ductile irons, it is not
e. ductile irons contain a magnesium carbide phase and grey cast irons do not

Use the bar diam. vs Jominy distance curves elsewhere on this website where needed.