Hardness test indenters

Precision matters, especially when it comes to hardness testing. At the heart of every hardness test lies the indenter: a small, often diamond-tipped specialized tool used to create an indentation on a material’s surface. This component plays an essential role in the accuracy and consistency of your results.

Whether you’re testing metals, ceramics or coatings, using the right indenter is essential for achieving reliable measurements and complying with international standards. GNEHM supplies high-quality hardness test indenters for all major hardness testing methods, including Vickers, Knoop, Brinell and Rockwell.

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A hardness test indenter is the part of a hardness tester that physically deforms the surface of a test specimen under a specified load. The size, shape and depth of the resulting indentation are used to calculate the material’s hardness value. 

The indenter must:

• Deliver consistent, repeatable penetration under load
• Be made of materials harder than the specimen
• Retain its shape even after repeated use

The choice of indenter impacts not only the accuracy of the measurement, but also its compliance with testing standards such as ISO 6507 (Vickers), ISO 6508 (Rockwell), and ASTM E10 (Brinell). 

How indenters work

Hardness test indenters function in four steps:

1. Contact: the indenter is pressed into the surface of the material.
2. Indentation: the indenter creates a permanent impression.
3. Measurement: the depth or size of the indentation is measured.
4. Hardness calculation: the hardness value is calculated based on the force applied and the resulting indentation.

Each of these steps relies on the quality, geometry and material of the indenter.

GNEHM offers a full range of hardness indenter types for all major test methods:

1. Vickers hardness test indenter

• Shape: four-sided diamond pyramid (angle 136°)
• Application: universal use, from metals to coatings
• Standard: ISO 6507, ASTM E92
• Precision-ground for consistent optical measurement

2. Knoop hardness test indenter

• Shape: asymmetrical elongated diamond pyramid
• Application: thin materials, coatings, microhardness testing
• Ideal for cross-sectional analysis

3. Brinell hardness test indenter

• Shape: hardened steel or tungsten carbide ball
• Diameter: typically 2.5, 5 or 10 mm
• Application: castings, forgings, coarse materials
• Standard: ISO 6506, ASTM E10

4. Rockwell hardness test indenter

• Types: diamond cone (Rockwell C, A, D scales) or steel or tungsten carbide balls (Rockwell B, F, etc)
• Standard: ISO 6508, ASTM E18
• Applications: broad industrial range from soft metals to hardened steels

For low-load Vickers and Knoop testing we offer microhardness indenters with extremely fine tip tolerances. Used for microelectronics, coatings and surface layers.

The performance and durability of an indenter are directly linked to its material. GNEHM offers indenters made from:

• Synthetic diamond: exceptional hardness and wear resistance; ideal for Vickers, Knoop and Rockwell C. 
• Tungsten carbide: high toughness, used for Brinell and Rockwell B. 
• Hardened steel: sometimes used in non-standard applications or legacy equipment. 

All indenters conform to applicable international standards such as:

• ISO 6507 (Vickers)
• ISO 6508 (Rockwell)
• ISO 6506 (Brinell)
• ASTM E92, E18, E10

Choosing the right indenter is critical to obtaining reliable, repeatable hardness results and maintaining compliance with international standards. Its shape, size and material must match the test method, load range and material properties to ensure accurate measurements and full standardization.

The right indenter depends on your:

• Test method and load range
• Material type and geometry
• Required measurement precision
• Applicable industry standards

For example:

• Use a Vickers diamond indenter for fine-grained steels or coatings.
• Use a Brinell ball indenter for softer, coarse-grained metals.
• Use a Knoop indenter for ultra-thin layers and microstructures.

Need assistance? Our experts can help you determine the best solution for your application, including compatibility with both GNEHM and third-party testers. 

Whether you need a standard Vickers indenter or a custom Knoop tip for microhardness testing, GNEHM delivers Swiss-engineered quality you can trust. 

GNEHM indenters are:

• Manufactured with ultra-high precision
• Compatible with GNEHM hardness testing machines
• Available for custom applications
• Individually inspected for geometry and tip quality

Looking for precision hardness test indenters?

Whether you’re testing high-strength alloys or delicate coatings, GNEHM offers a full range of standard and custom indenters to suit your needs. Request a quote or contact our team for specifications, pricing and expert support. 

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