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) A, B

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Rockwell C
Hardness
Number
150 kgf
(HRC)		 Vickers
Hardness
Number
(HV)		 Brinell Hardness 
Number C		 Knoop
Hardness,
Number
500-gf and
Over (HK)		 Rockwell Hardness Number Rockwell Superficial 
Hardness Number		 Scleroscope
Hardness
Number D		 Rockwell C
Hardness
Number
150 kgf
(HRC)
10-mm
Standard Ball,
3000-kgf
(HBS)		 10-mm
Carbide Ball,
3000-kgf
(HBW)		 A Scale,
60-kgf (HRA)		 D Scale,
100-kgf (HRD)		 15-N Scale,
15-kgf
(HR 15-N)		 30-N Scale,
30-kgf
(HR 30-N)		 45-N Scale,
45-kgf
(HR 45-N)
68 940 --- --- 920 85.6 76.9 93.2 84.4 75.4 97.3 68
67 900 --- --- 895 85.0 76.1 92.9 83.6 74.2 95.0 67
66 865 --- --- 870 84.5 75.4 92.5 82.8 73.3 92.7 66
65 832 --- (739) 846 83.9 74.5 92.2 81.9 72.0 90.6 65
64 800 --- (722) 822 83.4 73.8 91.8 81.1 71.0 88.5 64
63 772 --- (705) 799 82.8 73.0 91.4 80.1 69.9 86.5 63
62 746 --- (688) 776 82.3 72.2 91.1 79.3 68.8 84.5 62
61 720 --- (670) 754 81.8 71.5 90.7 78.4 67.7 82.6 61
60 697 --- (654) 732 81.2 70.7 90.2 77.5 66.6 80.8 60
59 674 --- 634 710 80.7 69.9 89.8 76.6 65.5 79.0 59
58 653 --- 615 690 80.1 69.2 89.3 75.7 64.3 77.3 58
57 633 --- 595 670 79.6 68.5 88.9 74.8 63.2 75.6 57
56 613 --- 577 650 79.0 67.7 88.3 73.9 62.0 74.0 56
55 595 --- 560 630 78.5 66.9 87.9 73.0 60.9 72.4 55
54 577 --- 543 612 78.0 66.1 87.4 72.0 59.8 70.9 54
53 560 --- 525 594 77.4 65.4 86.9 71.2 58.6 69.4 53
52 544 (500) 512 576 76.8 64.6 86.4 70.2 57.4 67.9 52
51 528 (487) 496 558 76.3 63.8 85.9 69.4 56.1 66.5 51
50 513 (475) 481 542 75.9 63.1 85.5 68.5 55.0 65.1 50
49 498 (464) 469 526 75.2 62.1 85.0 67.6 53.8 63.7 49
48 484 451 455 510 74.7 61.4 84.5 66.7 52.5 62.4 48
47 471 442 443 495 74.1 60.8 83.9 65.8 51.4 61.1 47
46 458 432 432 480 73.6 60.0 83.5 64.8 50.3 59.8 46
Rockwell C
Hardness
Number
150 kgf
(HRC)		 Vickers
Hardness
Number
(HV)		 Brinell Hardness 
Number C		 Knoop
Hardness,
Number
500-gf and
Over (HK)		 Rockwell Hardness Number Rockwell Superficial 
Hardness Number		 Scleroscope
Hardness
Number D		 Rockwell C
Hardness
Number
150 kgf
(HRC)
10-mm
Standard Ball,
3000-kgf
(HBS)		 10-mm
Carbide Ball,
3000-kgf
(HBW)		 A Scale,
60-kgf (HRA)		 D Scale,
100-kgf (HRD)		 15-N Scale,
15-kgf
(HR 15-N)		 30-N Scale,
30-kgf
(HR 30-N)		 45-N Scale,
45-kgf
(HR 45-N)
45 446 421 421 466 73.1 59.2 83.0 64.0 49.0 58.5 45
44 434 409 409 452 72.5 58.5 82.5 63.1 47.8 57.3 44
43 423 400 400 438 72.0 57.7 82.0 62.2 46.7 56.1 43
42 412 390 390 426 71.5 56.9 81.5 61.3 45.5 54.9 42
41 402 381 381 414 70.9 56.2 80.9 60.4 44.3 53.7 41
40 392 371 371 402 70.4 55.4 80.4 59.5 43.1 52.6 40
39 382 362 362 391 69.9 54.6 79.9 58.6 41.9 51.5 39
38 372 353 353 380 69.4 53.8 79.4 57.7 40.8 50.4 38
37 363 344 344 370 68.9 53.1 78.8 56.8 39.6 49.3 37
36 354 336 336 360 68.4 52.3 78.3 55.9 38.4 48.2 36
35 345 327 327 351 67.9 51.5 77.7 55.0 37.2 47.1 35
34 336 319 319 342 67.4 50.8 77.2 54.2 36.1 46.1 34
33 327 311 311 334 66.8 50.0 76.6 53.3 34.9 45.1 33
32 318 301 301 326 66.3 49.2 76.1 52.1 33.7 44.1 32
31 310 294 294 318 65.8 48.4 75.6 51.3 32.5 43.1 31
30 302 286 286 311 65.3 47.7 75.0 50.4 31.3 42.2 30
29 294 279 279 304 64.8 47.0 74.5 49.5 30.1 41.3 29
28 286 271 271 297 64.3 46.1 73.9 48.6 28.9 40.4 28
27 279 264 264 290 63.8 45.2 73.3 47.7 27.8 39.5 27
26 272 258 258 284 63.3 44.6 72.8 46.8 26.7 38.7 26
25 266 253 253 278 62.8 43.8 72.2 45.9 25.5 37.8 25
24 260 247 247 272 62.4 43.1 71.6 45.0 24.3 37.0 24
23 254 243 243 266 62.0 42.1 71.0 44.0 23.1 36.3 23
22 248 237 237 261 61.5 41.6 70.5 43.2 22.0 35.5 22
21 243 231 231 256 61.0 40.9 69.9 42.3 20.7 34.8 21
20 238 226 226 251 60.5 40.1 69.4 41.5 19.6 34.2 20

A In the table headings, force refers to total test forces.
B Appendix X1 contains equations converting determined hardness scale numbers to Rockwell C hardness numbers for non-austenitic steels.
C The Brinell hardness numbers in parentheses are outside the range recommended for Brinell hardness testing in 8.1 of Test Method E 10.
D These Scleroscope hardness conversions are based on Vickers—Scleroscope hardness relationships developed from Vickers hardness data provided by the National Bureau of Standards for 13 steel reference blocks, Scleroscope hardness values obtained on these blocks by the Shore Instrument and Mfg. Co., Inc., the Roll Manufacturers Institute, and members of this institute, and also on hardness conversions previously published by the American Society for Metals and the Roll Manufacturers Institute.

Approximate Hardness Conversion Numbers for Non-Austenitic Steels (Rockwell B Hardness Range) A, B

Rockwell B
Hardness
Number,
100-kgf
(HRB)		 Vickers
Hardness
Number
(HV)		 Brinell Hardness
Number,
3000-kgf,
(HBS)		 Knoop Hardness
Number,
500-gf, and
Over
(HK)		 Rockwell A
Hardness
Number,
60-kgf,
(HRA)		 Rockwell F
Hardness
Number,
60-kgf,
(HRF)		 Rockwell Superficial Hardness Number Rockwell B
Hardness
Number,
100-kgf,
(HRB)
15-T Scale,
15-kgf,
(HR 15-T)		 30-T Scale,
30-kgf,
(HR 30-T)		 45-T Scale,
45-kgf,
(HR 45-T)
100 240 240 251 61.5 --- 93.1 83.1 72.9 100
99 234 234 246 60.9 --- 92.8 82.5 71.9 99
98 228 228 241 60.2 --- 92.5 81.8 70.9 98
97 222 222 236 59.5 --- 92.1 81.1 69.9 97
96 216 216 231 58.9 --- 91.8 80.4 68.9 96
95 210 210 226 58.3 --- 91.5 79.8 67.9 95
94 205 205 221 57.6 --- 91.2 79.1 66.9 94
93 200 200 216 57.0 --- 90.8 78.4 65.9 93
92 195 195 211 56.4 --- 90.5 77.8 64.8 92
91 190 190 206 55.8 --- 90.2 77.1 63.8 91
90 185 185 201 55.2 --- 89.9 76.4 62.8 90
89 180 180 196 54.6 --- 89.5 75.8 61.8 89
88 176 176 192 54.0 --- 89.2 75.1 60.8 88
87 172 172 188 53.4 --- 88.9 74.4 59.8 87
86 169 169 184 52.8 --- 88.6 73.8 58.8 86
85 165 165 180 52.3 --- 88.2 73.1 57.8 85
84 162 162 176 51.7 --- 87.9 72.4 56.8 84
83 159 159 173 51.1 --- 87.6 71.8 55.8 83
82 156 156 170 50.6 --- 87.3 71.1 54.8 82
81 153 153 167 50.0 --- 86.9 70.4 53.8 81
80 150 150 164 49.5 --- 86.6 69.7 52.8 80
79 147 147 161 48.9 --- 86.3 69.1 51.8 79
Rockwell B
Hardness
Number,
100-kgf
(HRB)		 Vickers
Hardness
Number
(HV)		 Brinell Hardness
Number,
3000-kgf,
(HBS)		 Knoop Hardness
Number,
500-gf, and
Over
(HK)		 Rockwell A
Hardness
Number,
60-kgf,
(HRA)		 Rockwell F
Hardness
Number,
60-kgf,
(HRF)		 Rockwell Superficial Hardness Number Rockwell B
Hardness
Number,
100-kgf,
(HRB)
15-T Scale,
15-kgf,
(HR 15-T)		 30-T Scale,
30-kgf,
(HR 30-T)		 45-T Scale,
45-kgf,
(HR 45-T)
78 144 144 158 48.4 --- 86.0 68.4 50.8 78
77 141 141 155 47.9 --- 85.6 67.7 49.8 77
76 139 139 152 47.3 --- 85.3 67.1 48.8 76
75 137 137 150 46.8 99.6 85.0 66.4 47.8 75
74 135 135 147 46.3 99.1 84.7 65.7 46.8 74
73 132 132 145 45.8 98.5 84.3 65.1 45.8 73
72 130 130 143 45.3 98.0 84.0 64.4 44.8 72
71 127 127 141 44.8 97.4 83.7 63.7 43.8 71
70 125 125 139 44.3 96.8 83.4 63.1 42.8 70
69 123 123 137 43.8 96.2 83.0 62.4 41.8 69
68 121 121 135 43.3 95.6 82.7 61.7 40.8 68
67 119 119 133 42.8 95.1 82.4 61.0 39.8 67
66 117 117 131 42.3 94.5 82.1 60.4 38.7 66
65 116 116 129 41.8 93.9 81.8 59.7 37.7 65
64 114 114 127 41.4 93.4 81.4 59.0 36.7 64
63 112 112 125 40.9 92.8 81.1 58.4 35.7 63
62 110 110 124 40.4 92.2 80.8 57.7 34.7 62
61 108 108 122 40.0 91.7 80.5 57.0 33.7 61
60 107 107 120 39.5 91.1 80.1 56.4 32.7 60
59 106 106 118 39.0 90.5 79.8 55.7 31.7 59
58 104 104 117 38.6 90.0 79.5 55.0 30.7 58
57 103 103 115 38.1 89.4 79.2 54.4 29.7 57
56 101 101 114 37.7 88.8 78.8 53.7 28.7 56
55 100 100 112 37.2 88.2 78.5 53.0 27.7 55
54 --- --- 111 36.8 87.7 78.2 52.4 26.7 54
Rockwell B
Hardness
Number,
100-kgf
(HRB)		 Vickers
Hardness
Number
(HV)		 Brinell Hardness
Number,
3000-kgf,
(HBS)		 Knoop Hardness
Number,
500-gf, and
Over
(HK)		 Rockwell A
Hardness
Number,
60-kgf,
(HRA)		 Rockwell F
Hardness
Number,
60-kgf,
(HRF)		 Rockwell Superficial Hardness Number Rockwell B
Hardness
Number,
100-kgf,
(HRB)
15-T Scale,
15-kgf,
(HR 15-T)		 30-T Scale,
30-kgf,
(HR 30-T)		 45-T Scale,
45-kgf,
(HR 45-T)
53 --- --- 110 36.3 87.1 77.9 51.7 25.7 53
52 --- --- 109 35.9 86.5 77.5 51.0 24.7 52
51 --- --- 108 35.5 86.0 77.2 50.3 23.7 51
50 --- --- 107 35.0 85.4 76.9 49.7 22.7 50
49 --- --- 106 34.6 84.8 76.6 49.0 21.7 49
48 --- --- 105 34.1 84.3 76.2 48.3 20.7 48
47 --- --- 104 33.7 83.7 75.9 47.7 19.7 47
46 --- --- 103 33.3 83.1 75.6 47.0 18.7 46
45 --- --- 102 32.9 82.6 75.3 46.3 17.7 45
44 --- --- 101 32.4 82.0 74.9 45.7 16.7 44
43 --- --- 100 32.0 81.4 74.6 45.0 15.7 43
42 --- --- 99 31.6 80.8 74.3 44.3 14.7 42
41 --- --- 98 31.2 80.3 74.0 43.7 13.6 41
40 --- --- 97 30.7 79.7 73.6 43.0 12.6 40
39 --- --- 96 30.3 79.1 73.3 42.3 11.6 39
38 --- --- 95 29.9 78.6 73.0 41.6 10.6 38
37 --- --- 94 29.5 78.0 72.7 41.0 9.6 37
36 --- --- 93 29.1 77.4 72.3 40.3 8.6 36
35 --- --- 92 28.7 76.9 72.0 39.6 7.6 35
34 --- --- 91 28.2 76.3 71.7 39.0 6.6 34
33 --- --- 90 27.8 75.7 71.4 38.3 5.6 33
32 --- --- 89 27.4 75.2 71.0 37.6 4.6 32
31 --- --- 88 27.0 74.6 70.7 37.0 3.6 31
30 --- --- 87 26.6 74.0 70.4 36.3 2.6 30

A In table headings, kgf refers to total test force.
B Appendix X2 contains equations converting determined hardness numbers to Rockwell B hardness numbers for non-austenitic steels. Refer to 1.11 before using conversion equations.

Approximate Hardness Conversion Numbers for Nickel and High-Nickel Alloys A,B,C

NOTE 1—The use of hardness scales for hardness values shown in parentheses is not recommended since they are beyond the ranges recommended for accuracy. Such values are shown for comparative purposes only, where comparisons may be desired and the recommended machine and scale are not available.

A In table headings, kgf or gf refers to total test force.
B Appendix X3 contains equations converting determined hardness scale numbers to Vickers hardness numbers for nickel and high-nickel alloys. Refer to 1.11 before using conversion equations.
C Note that in Table 5 of Test Method E 10 (appears in the Annual Book of ASTM Standards, Vol 03.01), the use of a 3000-kgf force is recommended (but not mandatory) for material in the hardness range from 96 to 600 HV, and a 1500-kgf force is recommended (but not mandatory) for material in the hardness range from 48 to 300 HV. These recommendations are designed to limit impression diameters to the range from 2.50 to 6.0 mm. The Brinell hardness numbers in this conversion table are based on tests using a 3000-kgf force. When the 1500-kgf force is used for the softer nickel and high-nickel alloys, these conversion relationships do not apply.
 
ASTM A 370 Mechanical Testing of Steel Products (Go To Page 2)
Conversion Tables for Hardness Scales-Cast Rolls
Hardness Scales Conversion Table - Forged Rolls
Steel Hardness Conversion Table