Foundations of Materials Science and Engineering
6th Edition
ISBN: 9781259696558
Author: SMITH
Publisher: MCG
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Chapter 9.13, Problem 78AAP
(a)
To determine
Express the Rockwell C hardness for 80mm diameter 4340 steel bar at its surface.
(b)
To determine
Express the Rockwell C hardness for 60mm diameter 4140 long steel bar at its center.
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Check out a sample textbook solutionStudents have asked these similar questions
If a eutectoid steel sample is heated to 800°C and then quenched in a cold-water bath then
what would be the possible microstructure? Draw the microstructure and label it.
Q1: Austenitized 40 mm diameter 5140 alloy steel bar is quenched in agitated oil. Predict what is the
Rockwell hardness of this bar will be at (a) its surface and (b) its center (c) What do you think about
the difference in hardness number between the center and surface (d) Differentiate between hardness
and hardenability (e) Rank the steels in the figure below from lowest to highest hardenability and
explain why.
Cooling rate at 700°C (°C/sec)
300
150
011/3 55
100
600
Bar diameter (mm)
80
60
40
20
0
OLL
0
0
ww
25 12.5 8
5
S
--------------
M-R
10
3/4-R
Agitated oil
15 20
1/4
3/4
Distance from quenched end. De
(Jominy distance)
5.5
4
3
Bar diameter (in.)
0
25 mm
1 in.
Hardness (Rockwell C)
Where (C = center, S = surface, M-R mid-radius)
65
60
55
50
45
40
35
30
25
20
15
10
0
10
1
20
Distance from quenched end (mm)
5140
1
30
L
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32
Distance from quenched end (sixteenths of an inch)
4340
40
9840
4140
8640
50
Determine the structural constitution of a steel with 0.4% carbon at 727ºC during its cooling. Suggestion: Calculate using the lever rule
Chapter 9 Solutions
Foundations of Materials Science and Engineering
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