ASTM A 370 Mechanical Testing of Steel Products

ASTM A370 Specifications For Mechanical Testing of Steel Products

Approximate Hardness Conversion Numbers for Austenitic Steels 
(Rockwell C to other Hardness Numbers) as used in ASTM A370

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Rockwell C Scale, 150-kgf
Load, Diamond Penetrator		 Rockwell A Scale, 60-kgf
Load, Diamond Penetrator		 Rockwell Superficial Hardness
15N Scale, 15-kgf Load,
Diamond Penetrator		 30N Scale, 30-kgf Load,
Diamond Penetrator		 45N Scale, 45-kgf Load,
Diamond Penetrator
48 74.4 84.1 66.2 52.1
47 73.9 83.6 65.3 50.9
46 73.4 83.1 64.5 49.8
45 72.9 82.6 63.6 48.7
44 72.4 82.1 62.7 47.5
43 71.9 81.6 61.8 46.4
42 71.4 81.0 61.0 45.2
41 70.9 80.5 60.1 44.1
40 70.4 80.0 59.2 43.0
39 69.9 79.5 58.4 41.8
38 69.3 79.0 57.5 40.7
37 68.8 78.5 56.6 39.6
36 68.3 78.0 55.7 38.4
35 67.8 77.5 54.9 37.3
34 67.3 77.0 54.0 36.1
33 66.8 76.5 53.1 35.0
32 66.3 75.9 52.3 33.9
31 65.8 75.4 51.4 32.7
30 65.3 74.9 50.5 31.6
29 64.8 74.4 49.6 30.4
28 64.3 73.9 48.8 29.3
27 63.8 73.4 47.9 28.2
26 63.3 72.9 47.0 27.0
25 62.8 72.4 46.2 25.9
24 62.3 71.9 45.3 24.8
23 61.8 71.3 44.4 23.6
22 61.3 70.8 43.5 22.5
21 60.8 70.3 42.7 21.3
20 60.3 69.8 41.8 20.2

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