Hardness Conversion Chart

*The following chart applies to plain carbon, low-alloy steels, cast steel and to a limited extent high-alloy and/or work hardened steel*

 

Brinell 3000kg Load 10mm Ball Rockwell Approximate Tensile Strength (PSI)
Diameter, mm Hardness Number B Scale C Scale
2.85 461 – 48.5 242,000
2.90 444 – 47.1 230,000
2.95 429 – 45.7 219,000
3.00 415 – 44.5 212,000
3.05 401 – 43.1 202,000
3.10 388 – 41.8 193,000
3.15 375 – 40.4 184,000
3.20 363 – 39.1 177,000
3.25 352 110.0 37.9 170,000
3.30 341 109.0 36.6 163,000
3.35 331 108.5 35.5 158,000
3.40 321 108.0 34.3 152,000
3.45 311 107.5 33.1 147,000
3.50 302 107.0 32.1 143,000
3.55 293 106.0 30.9 139,000
3.60 285 105.5 29.9 136,000
3.65 277 104.5 28.8 131,000
3.70 269 104.0 27.6 128,000
3.75 262 103.0 26.6 125,000
3.80 255 102.0 25.4 121,000
3.85 248 101.0 24.2 118,000
3.90 241 100.0 22.8 114,000
3.95 235 99.0 21.7 111,000
4.00 229 98.2 20.5 109,000
4.05 223 97.3 18.8 104,000
4.10 217 96.4 17.5 103,000
4.15 212 95.5 16.0 100,000
4.20 207 94.6 15.2 99,000
4.25 201 93.8 13.8 97,000
4.30 197 92.8 12.7 94,000
4.35 192 91.9 11.5 92,000
4.40 187 90.7 10.0 90,000
4.45 183 90.0 9.0 89,000
4.50 179 89.0 8.0 88,000
4.55 174 87.8 6.4 86,000
4.60 170 86.8 5.4 84,000
4.65 167 86.0 4.4 83,000
4.70 163 85.0 3.3 82,000
4.80 156 82.9 0.9 80,000
4.90 149 80.8 – –
5.00 143 78.7 – –
5.10 137 76.4 – –
5.20 131 74.0 – –
5.30 126 72.0 – –
5.40 121 69.8 – –
5.50 116 67.6 – –
5.60 111 65.7 – –