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# 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:

160 - 600 3000
80 - 300 1500
26 - 100 500

### Typical Brinell Hardness Numbers for Metals

Brinell Hardness Number vs. Material
MaterialBrinell Hardness Number
Soft brass 60
Mild steel 130
Annealed chissel steel 235
White cast iron 415
Nitrided surface 750

### Steel Hardness versus Strength

Steel Hardness versus Strength
BrinellVickers Rockwell Equivalent Rm

Impression  Diameter
(mm)

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

## Related Topics

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## Citation

• The Engineering ToolBox (2008). Brinell Hardness Number - BHN. [online] Available at: https://www.engineeringtoolbox.com/bhn-brinell-hardness-number-d_1365.html [Accessed Day Month Year].

Modify the access date according your visit.

7.8.15

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