Brinell Hardness Number - BHN
The Brinell hardness test of metals and alloys.
The Brinell hardness test is commonly used to determine the hardness of materials like metals and alloys.
The test is achieved by applying a known load to the surface of the tested material through a hardened steel ball of known diameter. The diameter of the resulting permanent impression in the tested metal is measured and the Brinell Hardness Number calculated as
BHN = 2 P / (π D (D - (D2 - d2)1/2)) (1)
where
BHN = Brinell Hardness Number
P = load on the indenting tool (kg)
D = diameter of steel ball (mm)
d = measure diameter at the rim of the impression (mm)
It is desirable that the test load are limited to a impression diameter in the range of 2.5 to 4.75 mm.
Approximate loads and Brinell Hardness Numbers:
| Brinell Hardness Number | Load (kg) |
|---|---|
| 160 - 600 | 3000 |
| 80 - 300 | 1500 |
| 26 - 100 | 500 |
Typical Brinell Hardness Numbers for Metals
| Material | Brinell Hardness Number |
|---|---|
| Soft brass | 60 |
| Mild steel | 130 |
| Annealed chissel steel | 235 |
| White cast iron | 415 |
| Nitrided surface | 750 |
Steel Hardness versus Strength
For full table - rotate the screen!
| Brinell | Vickers | Rockwell | Equivalent Rm | ||||
|---|---|---|---|---|---|---|---|
|
|
Hardness HB |
Hardness HV |
Hardness B |
Hardness C |
(tonf/in2) |
(kgf/mm2) |
(N/mm2) |
| 2.50 | 601 | 640 | - | 57.0 | - | - | - |
| 2.55 | 578 | 615 | - | 56.0 | - | - | - |
| 2.60 | 555 | 591 | 120 | 54.5 | - | - | - |
| 2.65 | 534 | 569 | 119 | 53.5 | - | - | - |
| 2.70 | 514 | 547 | 119 | 52.0 | - | - | - |
| 2.75 | 495 | 528 | 117 | 51.0 | - | - | - |
| 2.80 | 477 | 508 | 117 | 49.5 | - | - | - |
| 2.85 | 461 | 491 | 116 | 48.5 | 101 | 160 | 1569 |
| 2.90 | 444 | 474 | 115 | 47.0 | 98 | 155 | 1520 |
| 2.95 | 429 | 455 | 115 | 45.5 | 95 | 150 | 1471 |
| 3.00 | 415 | 440 | 114 | 44.5 | 92 | 145 | 1422 |
| 3.05 | 401 | 425 | 113 | 43.0 | 88 | 139 | 1363 |
| 3.10 | 388 | 410 | 112 | 42.0 | 85 | 134 | 1314 |
| 3.15 | 375 | 396 | 112 | 40.5 | 82 | 129 | 1265 |
| 3.20 | 363 | 383 | 110 | 39.0 | 80 | 126 | 1236 |
| 3.25 | 352 | 372 | 110 | 38.0 | 77 | 121 | 1187 |
| 3.30 | 341 | 360 | 109 | 36.5 | 75 | 118 | 1157 |
| 3.35 | 331 | 350 | 109 | 35.5 | 73 | 114 | 1118 |
| 3.40 | 321 | 339 | 108 | 34.5 | 71 | 111 | 1089 |
| 3.45 | 311 | 328 | 108 | 33.0 | 68 | 107 | 1049 |
| 3.50 | 302 | 319 | 107 | 32.0 | 66 | 104 | 1020 |
| 3.55 | 293 | 309 | 106 | 31.0 | 64 | 101 | 990 |
| 3.60 | 285 | 301 | 105 | 30.0 | 63 | 99 | 971 |
| 3.65 | 277 | 292 | 104 | 29.0 | 61 | 96 | 941 |
| 3.70 | 269 | 284 | 104 | 27.5 | 59 | 93 | 912 |
| 3.75 | 262 | 276 | 103 | 26.5 | 58 | 91 | 892 |
| 3.80 | 255 | 269 | 102 | 25.5 | 56 | 89 | 873 |
| 3.85 | 248 | 261 | 102 | 24.0 | 55 | 87 | 853 |
| 3.90 | 241 | 253 | 100 | 23.0 | 53 | 84 | 824 |
| 3.95 | 235 | 247 | 99 | 22.0 | 51 | 81 | 794 |
| 4.00 | 229 | 241 | 98 | 20.5 | 50 | 79 | 775 |
| 4.05 | 223 | 235 | 97 | - | 49 | 77 | 755 |
| 4.10 | 217 | 228 | 96 | - | 48 | 76 | 745 |
| 4.15 | 212 | 223 | 96 | - | 46 | 73 | 716 |
| 4.20 | 207 | 218 | 95 | - | 45 | 71 | 696 |
| 4.30 | 197 | 208 | 93 | - | 43 | 68 | 667 |
| 4.40 | 187 | 197 | 91 | - | 41 | 65 | 637 |
| 4.50 | 179 | 189 | 89 | - | 39 | 62 | 608 |
| 4.60 | 170 | 179 | 87 | - | 36 | 57 | 559 |
| 4.70 | 163 | 172 | 85 | - | 35 | 55 | 539 |
| 4.80 | 156 | 165 | 83 | - | 34 | 54 | 530 |
| 4.90 | 149 | 157 | 81 | - | 32 | 51 | 500 |
| 5.00 | 143 | 150 | 79 | - | 31 | 49 | 481 |
| 5.10 | 137 | 144 | 77 | - | 31 | 49 | 481 |
| 5.20 | 131 | 138 | 74 | - | 30 | 47 | 461 |
| 5.30 | 126 | 133 | 72 | - | 29 | 46 | 451 |
| 5.40 | 121 | 127 | 70 | - | 28 | 44 | 431 |
| 5.50 | 116 | 122 | 68 | - | 27 | 43 | 422 |
| 5.60 | 111 | 117 | 66 | - | 26 | 41 | 402 |
| 5.70 | 107 | 113 | 64 | - | 25 | 39 | 382 |
| 5.80 | 103 | 108 | 61 | - | 24 | 38 | 373 |