Hardness
Conversion Table
Instantly convert between HRC, HB, HV and tensile strength (Rm). Precise results using linear interpolation based on ASTM E140.
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Select a scale and enter a value. Equivalents in all other scales will be calculated instantly.
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Hardness Conversion Reference Table
| HRC | HB | HV | Rm (MPa) |
|---|---|---|---|
| 20 | 226 | 238 | 730 |
| 25 | 253 | 266 | 820 |
| 30 | 286 | 302 | 950 |
| 35 | 331 | 350 | 1100 |
| 40 | 371 | 392 | 1250 |
| 45 | 421 | 446 | 1450 |
| 50 | 481 | 513 | 1650 |
| 55 | — | 595 | 1900 |
| 58 | — | 650 | 2050 |
| 60 | — | 697 | 2150 |
| 63 | — | 763 | 2300 |
| 65 | — | 832 | 2450 |
* Intermediate values are calculated using linear interpolation. Table is based on ASTM E140 standard. Brinell (HB) conversion is not defined for HRC > 52.
About Hardness Scales
HRC (Rockwell C)
Measured with a 120-degree diamond cone under 150 kgf load. The most common hardness scale for hardened steels and heat-treated parts. Valid range: 20-68 HRC.
HB (Brinell)
Measured by applying 3000 kgf load with a 10mm steel or tungsten carbide ball. Ideal for castings and softer steels. HB = F / (pi*D*(D-sqrt(D^2-d^2))/2).
HV (Vickers)
Measured with a 136-degree diamond pyramid. Can be used across all hardness ranges. Also preferred for micro-hardness measurements. HV = 1.854 * F / d^2.
Rm (Tensile Strength)
The maximum stress a material can withstand before fracture (MPa). The hardness-strength relationship is empirically determined and provides an approximate value.
Linear Interpolation Method
This calculator computes intermediate values between reference points using linear interpolation. For any x value between two known points (x0, y0) and (x1, y1):
Note: Conversion values are approximate and based on standard reference tables. Actual measured values should be used for critical engineering applications.
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