Hardness Conversions for Industrial Fasteners

Data for industrial bolts, machine screws and industrial fasteners from Elgin Fastener Group includes hardness conversions. The chart below shows a conversion between Brinell and Rockwell hardness numbers, as well as tensile strength.

Brinell Indentation Diameter mm Brinell Hardness Number Rockwell Hardness Number Rockwell Superficial Hardness Number Superficial Diamond Penetrator Tensile Strength (approx.) 1000 psi
Standard Ball Tungsten-Carbide Ball B Scale C Scale 15N Scale 30N Scale 45N Scale
2.45 627 58.70 89.60 76.30 65.10 347
2.50 601 57.30 89.00 75.10 63.50 328
2.55 578 56.00 88.40 73.90 62.10 313
2.60 555 54.70 87.80 72.70 60.60 298
2.65 534 53.50 87.20 71.60 59.20 288
2.70 514 52.10 86.50 70.30 57.60 274
2.75 495 51.00 85.90 69.40 56.10 264
2.80 477 49.60 85.30 68.20 54.50 252
2.85 461 48.50 84.70 67.20 53.20 242
2.90 444 47.10 84.00 65.80 51.50 230
2.95 429 429 45.70 83.40 64.60 49.90 219
3.00 415 415 44.50 82.80 63.50 48.40 212
3.05 401 401 43.10 82.00 62.30 46.90 202
3.10 388 388 41.80 81.40 61.10 45.30 193
3.15 375 375 40.40 80.60 59.90 43.60 184
3.20 363 363 39.10 80.00 58.70 42.00 177
3.25 352 352 37.90 79.30 57.60 40.50 170
3.30 341 341 36.60 78.60 56.40 39.10 163
3.35 331 331 35.50 78.00 55.40 37.80 158
3.40 321 321 34.30 77.30 54.30 36.40 152
3.45 311 311 33.10 76.70 53.30 34.40 147
3.50 302 302 32.10 76.10 52.20 33.80 143
3.55 293 293 30.90 75.50 51.20 32.40 139
3.60 285 285 29.90 75.00 50.30 31.20 136
3.65 277 277 28.80 74.40 49.30 29.90 131
3.70 269 269 27.60 73.70 48.30 28.50 128
3.75 262 262 26.60 73.10 47.30 27.30 125
3.80 255 255 25.40 72.50 46.20 26.00 121
3.85 248 248 24.20 71.70 45.10 24.50 118
3.90 241 241 100.00 22.80 70.90 43.90 22.80 114
3.95 235 235 99.00 21.70 70.00 42.90 21.50 111
4.00 229 229 98.20 20.50 69.70 41.90 20.10 109
4.05 223 223 97.30 104
4.10 217 217 63.40 103
4.15 212 212 95.50 100
4.20 207 207 94.60 99
4.25 201 201 93.80 97
4.30 197 197 92.80 94
4.35 192 192 91.90 92
4.40 187 187 90.70 90
4.45 183 183 90.00 89
4.50 179 179 89.00 88
4.55 174 174 87.80 86
4.60 170 170 86.80 84
4.65 167 167 86.00 83
4.70 163 163 85.00 82
4.80 156 156 82.90 80
4.90 149 149 80.80 73
5.00 143 143 78.70 71
5.10 137 137 76.40 67
5.20 131 131 74.00 65
5.30 126 126 72.00 63
5.40 121 121 69.00 60
5.50 116 116 67.60 58
5.60 111 111 65.70 56