Hardness test blocks

Certified reference blocks for hardness testing

Hardness test blocks are critical tools for verifying and calibrating your hardness testing machines. At GNEHM Testing we provide certified hardness reference blocks for Rockwell, Vickers, Brinell and Knoop hardness testing, ensuring reliable, repeatable and traceable results across all major standards including ISO, ASTM and JIS.

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What are hardness test blocks?

Hardness reference blocks are precisely manufactured calibration standards used to verify the accuracy of hardness testers. They are essential for quality assurance in production and laboratory environments, allowing users to regularly check and adjust their equipment in compliance with international norms. 

Each block is calibrated in accordance with ISO/IEC 17025 and fully conforms to the relevant testing standards, including ISO 6506 (Brinell), ISO 6507 (Vickers/Knoop), ISO 6508 (Rockwell) and ASTM E10, E18 and E92.

Hardness test blocks

GNEHM certified calibration blocks

Each GNEHM hardness test block is:

  • Calibrated under strict laboratory conditions
  • Supplied with full certification and traceability documentation
  • Engraved with the exact hardness value and serial number
  • Manufactured using high-quality, homogeneous materials

We offer both standard and custom reference blocks, calibrated according to your required scale and test force.

Why choose GNEHM reference blocks?

Our reference blocks are compatible with all GNEHM hardness testers as well as most machines from other major brands. Whether you operate a standalone Rockwell tester or a fully automated universal system, our blocks ensure optimal performance and consistent test accuracy.

  • Certified to ISO/IEC 17025
  • Compatible with Rockwell, Vickers, Brinell and Knoop methods
  • Fully traceable to international standards (ISO, ASTM, JIS)
  • Available with NADCAP-compliant grid (on request) for precise indent placement in microhardness testing
  • Long-lasting, durable materials (available in steel and aluminum)
  • Recalibration services available

Applications

GNEHM hardness calibration blocks are used worldwide in industries where precision and compliance are non-negotiable. Industries include:

  • Aerospace
  • Automotive manufacturing
  • Medical device production
  • Research & development
  • Quality control laboratories
  • Metal processing and heat treatment

Available standards & custom blocks

Gnehm hardness test blocks are available in all major testing methods and scales. See below for a detailed overview of the available standards and custom options.

  • Rockwell: HRC, HRB, superficial scales HRN, HRT
  • Vickers: HV1, HV5, HV10, HV30, microhardness HV0.1 to HV0.01 (microhardness HV0.1 available in calibrated values: 40, 70, 100, 150, 200)
  • Brinell: HBW 2.5/62.5, HBW 10/3000
  • Knoop: HK0.1, HK0.05, HK0.02, HK0.01

Looking for something specific? We also manufacture custom hardness calibration blocks to suit your unique testing setup.

Request a quote or more information

Need certified hardness test blocks for your lab or production line? Contact GNEHM today to request a quote, discuss your specifications or ask about the options.

Get in touch with our team

Switzerland (CH + FL) & Austria

GNEHM Harteprüfer AF

Global sales

GNEHM International LLC-FZ

FAQ about hardness reference blocks

A hardness reference block, or hardness test block, is a certified material with a known hardness value, used to verify and calibrate hardness testing machines.

Our blocks support Rockwell, Vickers, Brinell and Knoop testing methods, including microhardness testing.

We recommend recalibration annually, or as required by your quality assurance system or industry standard.

It means the hardness value assigned to each block is documented and traceable to an accredited reference laboratory under ISO/IEC 17025.

Yes. Reference blocks can be used repeatedly as long as the test surface remains undamaged and the block remains within tolerance. Overuse or excessive indentations may require replacement or recalibration.

Yes. We can produce certified blocks at specific hardness values and test forces according to your requirements. Just contact our team for options.