HEAT TREATMENT QUIZ

1Which of the following are the usual objectives of heat treatment (more than one)?

(a) increase hardness, (b) increase toughness, (c) recrystallization of the metal, (d) reduce brittleness, (e) reduce density, or (f) relieve stresses.

2 Of the following quenching media, which one produces the most rapid cooling rate?

(a) air, (b)brine, (c) oil, or (d) pure water.

3 On which one of the following metals can the treatment called austenitizing be performed? (a)aluminum alloys, (b) brass, (c) copper alloys, or (d) steel.

4 The treatment in which the brittleness of martensite is reduced is called which one of thefollowing?

(a) aging, (b) annealing, (c) austenitizing, (d) normalizing, (e) quenching, or (f)tempering.

5 The Jominy end-quench test is designed to indicate which one of the following?

(a) cooling rate,(b) ductility, (c) hardenability, (d) hardness, or (e) strength..6 In precipitation hardening, the hardening and strengthening of the metal occurs in which one of the following steps (one answer only)?

(a) aging, (b) quenching, or (c) solution treatment.

7 Which one of the following surface hardening treatments is the most common?

(a) boronizing, (b)carbonitriding, (c) carburizing, (d) chromizing, or (e) nitriding.

8 Which of the following are selective surface hardening methods (more than one)?

(a) electron beam heating, (b) fluidized bed furnaces, (c) induction heating, (d) laser beam heating, or (e) vacuum furnaces.

9 In normalizing, one of the following is not correct:

(A) it relieves internal stresses (B) it produces a uniform structure.(C) the rate of cooling is rapid (D) the rate of cooling is slow.

10 Fine grain sizes are obtained by

(A) slow cooling. (B) increasing nucleation rate.(C) decreasing growth rate (D) fast cooling.

11 Which one of the following is not the purpose of full annealing

(A) refines grains (B) induces softness.(C) removes strains and stresses (D) produces hardest material.

12 Annealing is generally done to impart

(A) hardness to the material (B) softness to the material(C) brittleness to the material (D) high conductivity to the material

13 Which of the following processes is used to harden a steel?

(A) Normalizing (B) Annealing(C) Carburizing (D) Quenching

14 The hardness of quenched Martensite

(A) increases with increasing carbon percentage.(B) decreases as carbon percentage increases.(C) first increases and then remains almost constant as the carbon percentage increases.(D) first increases and then decreases as carbon percentage increases.

15 The higher the temperature of temperinga) the softer will be the productb) the tougher will be the productc) the harder will be the productd) the stronger will be the product16. The hardenability is not affected by(1) air (2) chemical composition of steel(3) critical cooling rate (4) quenching medium and method of quenching

17. The slowest cooling rate is obtained when steel is quenched in

(1) air (2) brine (3) fused salt (4) mixture of oil and water 18. The fastest cooling rate is achieved when steel is quenched in(1) air (2) oil (3) water (4) brine 19. Which one of the following is not correct(1) Martensite has a BCC structure(2) Austenite has FCC structure(3) Martensite is a solid solution of carbon in BCC iron(4) The martensite which is formed during quenching is too brittle 20. Hardenability of steel is assessed by(1) impact test (2) Jominy end-quench test(3) hardness test (4) non-destructive test (2)21. Annealing temperature is(1) same as normalizing temperature(2) greater than normalizing temperature(3) less than normalizing temperature(4) sometimes greater and sometimes lesser than normalizing temperature 22. Heat treatment that requires heating a part below A1 temperature, i.e. between 550°C and 650° iscalled as(1) hardening (2) normalizing(3) process annealing (4) full annealing

ANSWERS

1 . (a), (b), (c), (d), and (f).2 (b)3 (d)4 (f)5 (c) The reader might be tempted to select (d) because the Jominy test indicateshardness; however, the reason for measuring hardness in the Jominy test is to measurehardenability.6 (a)7 (c)8 (a), (c), and (d).

9 d

10 a

11d12 b

13 d

14 c

15 a

16 1

171

18 4

19 1

20 2

21 3

22 3