Brinell Hardness Number Calculator (HBW)

Your details

Choose metric (Newtons and millimetres) or imperial (pound-force and inches).
Select the unit your testing machine reports the applied load in.
Force applied to the indenter during the test. Common standard loads are 500, 1500 and 3000 kgf.
kgf
Diameter of the tungsten carbide ball indenter. Standard sizes are 1, 2.5, 5 and 10 mm.
mm
Mean diameter of the circular indentation left in the material, measured as the average of two perpendicular readings.
mm
Brinell Hardness (HBW)Hard (e.g. tool steel, hardened)
254.7

Brinell Hardness Number per ISO 6506-1

Indentation area (A)11.783mm²
Indentation depth (h)0.3751mm
Load in Newtons29,419.9N
d/D ratio0.38
254.7 HBW
Very soft<50Soft50-100Medium100-200Hard200-350Very hard350-600Extreme600+

Brinell hardness: 254.7 HBW

  • Heat-treated medium-carbon and alloy steels typically fall in the 250-400 HBW range.
  • Your d/D ratio is 0.380, which is within the ISO 6506-1 valid range (0.24 to 0.60).
  • Brinell hardness cannot be used on surface-hardened or case-hardened parts because the large ball averages through the hard skin into the soft core.
  • The indentation depth is 0.375 mm. The test specimen should be at least 8 times this depth to avoid the support surface affecting the result.

Next stepIf you need a Rockwell or Vickers equivalent, apply the ASTM E140 conversion tables. For surface layers, Vickers or Knoop micro-hardness tests are more appropriate.

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