Indentation Hardness of a Material

Indentation Hardness Testing Services

Indentation hardness measures how resistant a material is when compressed. Hardness testing is a measure of indentation resistance and is characterized by being quick, easy, and non-destructive. A force is applied to an indenter such as a steel ball or diamond pyramid, and the size and depth of depressions on the material’s surface are measured with a microscope. There are different types of hardness testers available:

• Compare Hardness Testers

There are four scales to choose from when measuring the osmotic zone. The type of scale you use affects the type of equipment you use.

• Brinell Scale

Invented by Johan August Brinell in 1900, his Brinell scale was the first hardness scale used by engineers and metal fabricators. To perform the Brinell test, an indenter penetrates the material of interest. People prefer the Brinell scale when the Ultimate Tensile Strength (UTS) of steel also needs to be determined. Halve the hardness value on the Brinell scale to get UTS in pounds per square inch.

• Rockwell Scale

The Rockwell scale was invented by Hugh Rockwell and Stanley Rockwell in the early 20th century. This scale compares impressions from large loads to those from small loads. The Rockwell test preserves the material’s integrity better than the Brinell test. The Brinell test makes a big impression that can actually damage the material being tested.

• Vickers Scale

The Vickers scale was developed by Robert L. Smith and George E. Sandland in 1921 at Vickers Corporation. Vickers hardness measurements are often easier to determine than measurements on other scales. Unlike other tests, the Vicker’s indenter size does not affect the hardness calculations. 

• Shore Scale

Unlike other hardness scales that focus on metals, the Shore scale measures the hardness of elastomers, rubbers and polymers.

ASTM Standard for Indentation Hardness Testing

The most common ASTM standards for measuring indentation hardness are as follows:

• ASTM C730 – Standard Test Method for Knoop Indentation Hardness of Glass
• ASTM C1327 – Standard Test Method for Vickers Indentation Hardness of Advanced Ceramics
• ASTM D1474/D1474M – Standard Test Methods for Indentation Hardness of Organic Coatings
• ASTM A833 – Standard Test Method for Indentation Hardness of Metallic Materials by Comparison Hardness Testers 
• ASTM C849 – Standard Test Method for Knoop Indentation Hardness of Ceramic Whitewares
• ASTM C1326 – Standard Test Method for Knoop Indentation Hardness of Advanced Ceramics
• ASTM E103 – Standard Practice for Rapid Indentation Hardness Testing of Metallic Materials
• ASTM C661 – Standard Test Method for Indentation Hardness of Elastomeric-Type Sealants by Means of a Durometer

Common Uses of Indentation Hardness Testing

• Indentation testing is commonly used to measure the hardness of materials. 
• The primary purpose of hardness testing is to measure the resistance of materials to plastic deformation quantitatively.

Industrial Applications of Indentation Hardness Testing

• Hardness testing can be applied to evaluate material properties such as strength, ductility, and wear resistance.
• Helps to determine if a material or material treatment is suitable for its purpose.