A hardness tester measures how much a material resists a small indenter being pressed into it. Rockwell testers read hardness directly and are the usual choice in machine shops and heat treatment (HRC, HRB). Brinell testers use a larger ball for castings and soft metals; Vickers testers use a diamond pyramid for thin layers and case depth. Portable Leeb testers check large parts on site.
Quick facts
- Rockwell
- HRC for hardened steel, HRB for soft steel and brass
- Brinell
- HB, large ball, for castings and forgings
- Vickers
- HV, diamond pyramid, thin parts and case depth
- Portable
- Leeb (rebound) and ultrasonic testers
- Calibration
- Test blocks of known hardness
- Standards
- ISO 6508 (Rockwell), ISO 6506 (Brinell), ISO 6507 (Vickers)
Which test for which part
| Part | Test |
|---|---|
| Hardened steel parts, tools | Rockwell C |
| Soft steel, brass, aluminium | Rockwell B or Brinell |
| Castings and forgings | Brinell |
| Thin sheet, coatings, case depth | Vickers or micro-Vickers |
| Large parts that cannot be moved | Portable Leeb or ultrasonic |
Getting correct readings
- Test on a clean, flat surface
- Part must be thick enough for the test load
- Keep tests away from edges and earlier dents
- Check the machine on a test block every day
- Curved surfaces need a correction
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Materials
Questions
- Can I convert HRC to HB?
- Approximately, with conversion tables or our hardness converter; conversions are only estimates.
- Why do two testers give different readings?
- Surface finish, part support, calibration and test method all change the result; check both on the same test block.
- How accurate are portable testers?
- Good for checking large parts, but less precise than bench testers; they need the right material setting.
The figures on this page are typical values for guidance, written by Diemeco from standard engineering practice. They are not a specification: confirm grades and properties with the relevant standard or the supplier's mill test certificate, and tolerances with your workshop. Last checked 29 October 2026.