Fundamentals of Materials Science and Engineering: An Integrated Approach, 3e

GTBL042-11 GTBL042-Callister-v3 October 4, 2007 11:59

2nd Revised Pages

11.6 Continuous Cooling Transformation Diagrams • 429

Time (s)

Temperature (

°C)

Temperature (

°F)

10 –1 110102 103 104 105

200

400

800

600

1000

1200

Eutectoid temperature^1400

M (start)

100

0

200

300

400

Critical

cooling

rate

500

600

700

800

Martensite Pearlite

Martensite

+

Pearlite

Pearlite

Austenite

35

(^140) °C/s
°C/s
Figure 11.28
Continuous cooling
transformation
diagram for a
eutectoid iron–
carbon alloy and
superimposed
cooling curves,
demonstrating the
dependence of the
final microstructure
on the
transformations that
occur during cooling.
Time (s)
Temperature (
°C)
Temperature (
°F)
110102 103 104 105 106
200
400
800
600
1000
1200
1400
Eutectoid temperature
M (start)
100
0
200
300
(^400) Critical
cooling
rate
500
600
700
800
M M + B F + P
M + F +
P + B
M + F

• B
  0.006
  °C/s
  0.02
  °C/s
  Austenite Martensite
  Austenite
  Bainite "nose"
  Bainite
  Austenite
  Pearlite
  0.3
  °C/s
  8.3
  °C/s
  Austenite
  Ferrite
  Figure 11.29
  Continuous cooling
  transformation
  diagram for an alloy
  steel (type 4340) and
  several superimposed
  cooling curves
  demonstrating
  dependence of the
  final microstructure
  of this alloy on the
  transformations that
  occur during cooling.
  [Adapted from H. E.
  McGannon (Editor),
  The Making, Shaping
  and Treating of Steel,
  9th edition, United
  States Steel
  Corporation,
  Pittsburgh, 1971,
  p. 1096.]