Rockwell Hardness Testing

Rockwell hardness test is a fast test method with no optical read-out. Rockwell hardness is calculated by measuring the depth of a diamond or tungsten carbide ball indentation. Due to the relatively high loads used it is generally limited to larger sample geometries.

Conversion Table

The Rockwell methods are described by a number of scales characterized by a standard, an indenter type and a load.


  • HRE 1/8 inch diameter tungsten carbide ball indenter, 100 kgf major load
  • HR30N (Superficial Rockwell 30N-scale): Diamond cone indenter, 30 kgf major load

Rockwell Indenter type table

Overview of typical applications for Rockwell Scales

Rockwell typical applications


Rockwell is often used as a "quick test" on the production floor or in the laboratory, but is also used for more advanced tests, such as the Jominy (end quench) test (HRC).

Surface preparation

Macro hardness test

  • no surface preparation
  • ground


Rockwell loads table

  • Indentation time: 2-6 seconds
  • Sample thickness ASTM:At least 10 times the indentation depth for both indenters
  • Sample thickness ISO:At least 10 times the indentation depth when using diamond indenter. At least 15 times the indentation depth when using cemented carbide indenter
Applicable standards

Applicable Standards

  • ASTM E18
  • ISO 6508
  • JIS Z 2245

Knowledge leadership

Find new knowledge and inspiration by taking part in Struers training courses and e-Seminars. Gain valuable insights into the latest applications and preparation methods via knowledge sharing. Refresh your knowledge or learn new techniques together with our application experts. The choice is yours!