Rockwell scale
Sign in to saveAlso known as HRC, Rockwell hardness, Rockwell hardness C, Rockwell C hardness, Rockwell hardness scale
Rockwell hardness scale based on indentation hardness of a material with a 120° diamond spheroconical under 150 kgf
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Encyclopedic overview
A Rockwell hardness tester
The Rockwell hardness test is a hardness test based on indentation hardness of a material. The Rockwell test measures the depth of penetration of an indenter under a large load (major load) compared to the penetration made by a preload (minor load). There are different scales, denoted by a single letter, that use different loads or indenters. The result is a dimensionless number noted as HRA, HRB, HRC, etc., where the last letter is the respective Rockwell scale. Larger numbers correspond to harder materials.
Excerpted from Wikipedia’s “Rockwell scale” article, available under the CC BY-SA 4.0 licence.