Table 7. Graphical Comparison of Rockwell Hardness Scales
Rockwell Scales
A B C
D
E F
G
H K
15N 30N 45N 15T
30T
45T
TENSILE STRENGTH 1000 lb/in 2
88
70
94
80 86
20 30 40 50 60 70 77
70 77
Hard steels
100 120 140 160 180 200 250 300 350
60
90
80
70
50
60
60
40
80
70
Easily machined steels
50
30 40 50 60 70 80 90 94
30
50
93
70 72
80 82
100
70
42
20
40
60
100
90
70 80 90 60
90
60
90
70
Brasses and aluminum alloys
50
80
50
100
100
80
70
40
60
50
80
40
90
70
90
20 30 40 50 60
0 10 20 30
50
40 50 60
80
80
100
30
30 40
70 67
70
70
20
90
60
80
Source: George Dorian of GPDorian Co. Note: This chart is for the general comparison of Rockwell scales only.
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