ASTM E 140 Hardness Conversion Tables for Metals

ASTM E140 Standard Hardness Conversion Tables for Metals-Relationship Among Brinell Hardness, Vickers Hardness, Rockwell Hardness, Knoop Hardness, Superficial Hardness, and Scleroscope Hardness

Approximate Hardness Conversion Numbers for 
Non-Austenitic Steels (Rockwell C Hardness Range)

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Rockwell Hardness Number,
B Scale (100-kgf, 1⁄16-in.
(1.588-mm) ball) (HRB)		 Brinell Hardness Number
(3000-kgf, 10-mm ball)
(HBS)
100 256
99 248
98 240
97 233
96 226
95 219
94 213
93 207
92 202
91 197
90 192
89 187
88 183
87 178
86 174
85 170
84 167
83 163
82 160
81 156
80 153
79 150
78 147
77 144
76 142
75 139
74 137
73 135
72 132
71 130
70 128
69 126
68 124
67 122
66 120
65 118
64 116
63 114
62 113
61 111
60 110

Approximate Rockwell Hardness Conversion Numbers for Austenitic Stainless Steel Sheet A,B

Rockwell Hardness Number Rockwell Superficial Hardness Number
C Scale, 150-kgf
Diamond
Penetrator
(HRC)		 A Scale, 60-kgf,
Diamond Penetrator
(HRA)		 15-N Scale, 15-kgf,
Superficial
Diamond Penetrator
(HR 15-N)		 30-N Scale, 30-kgf,
Superficial
Diamond Penetrator
(HR 30-N)		 45-N Scale, 45-kgf,
Superficial
Diamond Penetrator
(HR 45-N)
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 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
B Scale, 100-kgf, 1/16-in. (1.588-mm) Ball (HRB) A Scale, 60-kgf, Diamond Penetrator (HRA) F Scale, 60-kgf, 1/16-in. (1.588-mm) Ball C (HRF) 15-T Scale, 15-kgf, 1/16-in. (1.588-mm) Ball (HR 15-T) 30-T Scale, 30-kgf, 1/16-in. (1.588-mm) Ball (HR 30-T) 45-T Scale, 45-kgf, 1/16-in. (1.588-mm) Ball (HR 45-T)
100
99
98
97
96
95
94
93
92
91
90
89
88
87
86
85
84
83
82
81
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
60

Standard deviation C
61.5
60.9
60.3
59.7
59.1
58.5
58.0
57.4
56.8
56.2
55.6
55.0
54.5
53.9
53.3
52.7
52.1
51.5
50.9
50.4
49.8
49.2
48.6
48.0
47.4
46.9
46.3
45.7
45.1
44.5
43.9
43.3
42.8
42.2
41.6
41.0
40.4
39.8
39.3
38.7
38.1
1.44
(113.9)
(113.2)
(112.5)
(111.8)
(111.1)
(110.5)
(109.8)
(109.1)
(108.4)
(107.8)
(107.1)
(106.4)
(105.7)
(105.0)
(104.4)
(103.7)
(103.0)
(102.3)
(101.7)
(101.0)
(100.3)
99.6
99.0
98.3
97.6
96.9
96.2
95.6
94.9
94.2
93.5
92.8
92.2
91.5
90.8
90.1
89.5
88.8
88.1
87.4
86.8
2.75
91.5
91.2
90.8
90.4
90.1
89.7
89.3
88.9
88.6
88.2
87.8
87.5
87.1
86.7
86.4
86.0
85.6
85.2
84.9
84.5
84.1
83.8
83.4
83.0
82.6
82.3
81.9
81.5
81.2
80.8
80.4
80.1
79.7
79.3
78.9
78.6
78.2
77.8
77.5
77.1
76.7
2.29
80.4
79.7
79.0
78.3
77.7
77.0
76.3
75.6
74.9
74.2
73.5
72.8
72.1
71.4
70.7
70.0
69.3
68.6
67.9
67.2
66.5
65.8
65.1
64.4
63.7
63.0
62.4
61.7
61.0
60.3
59.6
58.9
58.2
57.5
56.8
56.1
55.4
54.7
54.0
53.3
52.6
1.67
70.2
69.2
68.2
67.2
66.1
65.1
64.1
63.1
62.1
61.1
60.1
59.0
58.0
57.0
56.0
55.0
54.0
52.9
51.9
50.9
49.9
48.9
47.9
46.8
45.8
44.8
43.8
42.8
41.8
40.7
39.7
38.7
37.7
36.7
35.7
34.7
33.6
32.6
31.6
30.6
29.6
1.57

A In table headings, kgf or gf refers to total test force.
B Appendix X6 contains equations converting determined hardness numbers to Rockwell C and Rockwell B hardness numbers for austenitic stainless steel sheet. Refer to 1.11 before using conversion equations.
C Observed standard deviation of the inter-laboratory test data about the indicated conversion line.

 
ASTM A 370 Mechanical Testing of Steel Products (Go To Page 1)
Conversion Tables for Hardness Scales-Cast Rolls
Hardness Scales Conversion Table - Forged Rolls
Steel Hardness Conversion Table