Conversion between hardness scales｜Hardness Conversion Chart | Rockwell, Brinell, Vickers
How and Why to Convert Rockwell, Vickers, and Brinell Hardness Values？
Hardness conversion refers to estimating equivalent hardness values across different hardness scales, such as Rockwell (HR), Brinell (HBW), and Vickers (HV). This is essential when comparing test results, meeting standards, or using hardness tester equipment with specific limitations.
What Is Hardness Conversion?
Different hardness testing methods use unique indenters, test forces, and measurement criteria. Therefore, direct mathematical conversion is not universally applicable. Instead, conversion relies on empirical data and standard tables, such as those in ASTM E140 or ISO 18265.
Common Hardness Scales Compared
| Scale | Symbol | Indenter Type | Test Load Range |
|---|---|---|---|
| Rockwell | HR | Diamond cone or steel ball | 15 – 150 kgf |
| Brinell | HB or HBW | Tungsten carbide ball | 500 – 3000 kgf |
| Vickers | HV | Diamond pyramid | 1 gf – 100 kgf |
| Knoop | HK | Elongated diamond | Micro range |
| Leeb | HL | Rebound hammer | Portable testing |
Why Convert Between Hardness Scales?
- Cross-standard compliance: Different industries or clients require different hardness units.
- Lab-to-lab comparison: Not all facilities use the same test method.
- Instrument limitations: A lab may only have Rockwell testers, but Brinell values are needed.
Example Hardness Conversion Table (for Steels)
| Rockwell C (HRC) | Brinell (HBW) | Vickers (HV) |
|---|---|---|
| 20 | 225 | 220 |
| 30 | 285 | 280 |
| 40 | 370 | 390 |
| 50 | 500 | 540 |
| 60 | 650 | 750 |
Note: Exact values depend on material type and microstructure.
Important Notes on Hardness Conversion
- Conversion is material-dependent. Steels, aluminum, and plastics respond differently.
- Use ASTM E140 or ISO tables for reliable results, especially in critical applications.
- Always state the original and target scales in reports (e.g., "Converted from HRC to HBW").
Need Help with Specific Hardness Conversion?
If you're looking to convert a specific value (e.g., 62 HRC to HBW or 450 HV to HRC), we can assist with accurate estimations using standard references. Contact us or use a certified hardness conversion tool.
