Hardness Conversions
Hardness Conversions
Approximate relations between Brinell, Rockwell, Vickers and Knoop hardness and the tensile strengths of S.A.E. carbon and alloy construction steels.
| C | A | 15-N | 30-N | VICKERS | KNOOP | BRINELL | |
|---|---|---|---|---|---|---|---|
| 150 kg Diamond |
60 kg Diamond |
16 kg N Diamond |
30 kg N Diamond |
10 kg 136* Diamond |
500 Gr. & over |
3000 kg 10 mm Ball |
Approx. Tensile Strength ksi |
| Rockwell | Rockwell | Rockwell Superficial |
Rockwell Superficial |
Vickers | Knoop | Brinell** (Standard Ball) |
|
| 68 67 66 65 64 |
85.6 85.0 84.5 83.9 83.4 |
93.2 92.9 92.5 92.2 91.8 |
84.4 83.6 82.8 81.9 81.1 |
940 900 865 832 800 |
920 895 870 846 822 |
- - - - - |
inexact and only for steel |
| 63 62 61 60 59 |
82.8 82.3 81.8 81.2 80.7 |
91.4 91.1 90.7 90.2 89.8 |
80.1 79.3 78.4 77.5 76.5 |
772 746 720 697 674 |
799 776 754 732 710 |
- - - - - |
351 |
| 58 57 56 55 54 |
80.1 79.6 79.0 78.5 78.0 |
89.3 88.90 88.3 87.9 87.4 |
75.7 74.8 73.9 73.0 72.0 |
653 633 613 595 577 |
690 670 650 630 612 |
615 595 577 560 543 |
338 325 313 301 292 |
| 53 52 51 50 49 |
77.4 76.8 76.3 75.9 75.2 |
86.9 86.4 85.9 85.5 85.0 |
71.2 70.2 69.4 68.5 676.6 |
560 544 528 513 498 |
594 576 558 542 526 |
525 512 496 481 469 |
283 273 264 255 246 |
| 48 47 46 45 44 |
74.7 74.1 73.6 73.1 72.5 |
84.5 83.9 83.5 83.0 82.5 |
66.7 65.8 64.8 64.0 63.1 |
484 471 458 446 434 |
510 495 480 466 452 |
451 442 432 421 409 |
238 229 221 215 208 |
| 42 40 38 36 34 |
71.5 70.4 69.4 68.4 67.4 |
81.5 80.4 79.4 78.3 77.2 |
61.3 59.5 57.7 55.9 54.2 |
412 392 372 354 336 |
426 402 380 360 342 |
390 371 353 336 319 |
194 182 171 161 152 |
| 32 30 28 26 24 22 20 |
66.3 65.3 64.3 63.3 62.4 61.5 60.5 |
76.1 75.0 73.9 72.8 71.6 70.5 69.4 |
52.1 50.4 48.6 46.8 45.0 43.2 41.5 |
318 302 286 272 260 248 238 |
326 311 297 284 272 261 251 |
301 286 271 258 247 237 226 |
146 138 131 125 119 115 110 |
| B | F | 30-T | A | Knoop | Brinell | Tensile Strength |
|---|---|---|---|---|---|---|
| 100 kg 1/16" Ball |
60 kg 1/16" Ball |
30 kg 1/16" Ball |
60 kg Diamond |
500 Gr. | 3000 kg 10 mm Ball |
|
| Rockwell | Rockwell | Rockwell Superficial |
Rockwell | Knoop | Brinell | Thousand lbs. per sq. in. |
| 100 99 98 97 96 |
- - - - - |
83.1 82.5 81.8 81.1 80.4 |
61.5 60.9 60.2 59.5 58.9 |
251 246 241 236 231 |
240 234 228 222 216 |
116 114 109 104 102 |
| 95 94 93 92 91 |
- - - - - |
70.8 79.1 78.4 77.8 77.1 |
58.3 57.6 57.0 56.4 55.8 |
226 221 216 211 206 |
210 205 200 195 190 |
100 98 94 92 90 |
| 90 89 88 87 86 |
- - - - - |
76.4 75.8 75.1 74.4 73.8 |
55.2 54.6 54.0 53.4 52.8 |
201 196 192 188 184 |
185 180 176 172 169 |
89 88 86 84 83 |
| 85 84 83 82 81 |
- - - - - |
73.1 72.4 71.8 71.1 70.4 |
52.3 51.7 51.1 50.6 50.0 |
180 176 173 170 167 |
165 162 159 156 153 |
82 81 80 77 73 |
| 80 79 78 77 76 |
- - - - - |
69.7 69.1 68.4 67.7 67.1 |
49.5 48.9 48.4 47.9 47.3 |
164 161 158 155 152 |
150 147 144 141 139 |
72 70 69 68 67 |
| 75 74 72 71 68 |
99.6 99.1 98.0 96.8 95.6 |
66.4 65.7 64.4 63.1 61.7 |
46.8 46.3 45.3 44.3 43.3 |
150 147 143 139 135 |
137 135 130 125 121 |
66 65 63 61 59 |
| 66 64 62 60 58 |
94.5 93.4 92.2 91.1 90.0 |
60.4 59.0 57.7 56.4 55.0 |
42.3 41.4 40.4 39.5 38.6 |
131 127 124 120 117 |
117 114 110 107 104 |
Even for steel, tensile strength relation to hardness is inexact unless determined for specific material. See ASTM A370 |
| 56 54 52 50 48 |
88.8 87.7 86.5 85.4 84.3 |
53.7 52.4 51.0 49.7 48.3 |
37.7 36.8 35.9 35.0 34.1 |
114 111 109 107 105 |
101 *87 *85 *83 *81 |
|
| 46 44 42 40 38 |
83.1 82.0 80.8 79.7 78.6 |
47.0 45.7 44.3 43.0 41.6 |
33.3 32.4 31.6 30.7 29.9 |
103 101 99 97 95 |
*79 *78 *76 *74 *73 |
|
| 36 34 32 30 |
77.4 76.3 75.2 74.0 |
40.3 39.0 37.6 36.3 |
29.1 28.2 27.4 26.6 |
93 91 89 87 |
*71 *70 *68 *67 |
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