Rockwell Hardness Testing

Rockwell hardness test is a fast test method with no optical readout. 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: Two to six seconds
  • Sample thickness ASTM: At least ten times the indentation depth for both indenters.
  • Sample thickness ISO: At least ten times the indentation depth when using a diamond indenter. At least 15 times the indentation depth when using a cemented carbide indenter
Applicable Standards

Applicable Standards

  • ASTM E18
  • ISO 6508
  • JIS Z 2245

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