Struers - Ensuring Certainty / Knowledge / Hardness Testing / Rockwell Hardness testing (HR)
The Rockwell hardness test is a fast method, making it ideal for quick hardness testing. We give a definition of the Rockwell hardness test, as well as practical information of how to apply it in practice.
The Rockwell hardness test at a glance:
- Generally used for larger samples
- No optical readout
- Can be used for advanced tests
- Standards: ASTM E18, ISO 6508 and JIS Z 2245
See our complete range of Rockwell hardness testing machines.
See our Hardness Testing Conversion Poster
- Introduction
- About
- Application
- Equipment
- Find out more
The Rockwell hardness test is often used as a ‘quick test’ on the production floor or in the laboratory, mainly for metallic materials. However, it can also be used for more advanced tests, such as the Jominy test (End Quench Test). Due to the relatively high loads used, application of the Rockwell hardness test is generally limited to larger sample geometries.
The Rockwell test calculation
The Rockwell hardness test calculation (HR) is made by measuring the depth of an indentation made with a diamond or tungsten carbide ball.
Indenters
The Rockwell hardness test utilizes 1 of 5 different indenters:
- Diamond cone
- Tungsten ball in sizes 1/16", 1/8", 1/4", or 1/2"
Main loads
The Rockwell hardness test utilizes 1 of 6 different main loads:
- 15 kgf, 30 kgf, 45 kgf, 60 kgf, 100 kgf, or 150 kgf
In total, this gives 30 different Rockwell scales. Each one is characterized by a different combination of indenter type and main load, and is suitable for a particular material or application (for example, HRA, HRB, HRC, HR30N).
Definition of the Rockwell hardness test method
The Rockwell hardness test methods are described by a number of scales, characterized by a standard, an indenter type, and a load.
Examples of Rockwell hardness test methods:
- HRE 1/8” diameter tungsten carbide ball indenter, 100 kgf major load
- HR30N (Superficial Rockwell 30N-scale): Diamond cone indenter, 30 kgf major load
Overview of typical applications for Rockwell hardness scales
APPLICATION OF THE ROCKWELL HARDNESS TEST
Surface preparation
Before application of the Rockwell hardness test, you must prepare the surface of the material to be tested. The required surface condition for the Rockwell hardness test depends on the load used.
The Rockwell hardness test is used for macro hardness tests, which are generally defined as tests that use indentation loads below or equal to 1 kgf. Therefore, a ground surface is usually sufficient, and sometimes no preparation is required.
Loads
- Indentation time: 2-6 seconds
- Sample thickness ASTM: At least 10 times the indentation depth for both indenters
- Sample thickness ISO: Diamond indenter: At least 10 times the indentation depth. Tungsten carbide indenter: At least 15 times the indentation depth
Jominy testing
A standardized test procedure used to determine the hardenability of steel, the Jominy test (End Quench Test) can be performed using either the Vickers or Rockwell hardness test method. When selecting which to use, you should consider relevant standards, as well as the usual criteria when choosing between different types of hardness test.
Find out more about the Jominy test method on our Vickers hardness test page
ROCKWELL HARDNESS TESTING MACHINES (HARDNESS TESTERS)
Hardness testing is key in most quality control procedures. That’s why we provide a complete range of Rockwell hardness testing machines and accessories, from equipment for lab application of hardness testing up to heavy-duty hardness testers for large-scale production sites.
All our Rockwell hardness testers are designed to deliver the long-term performance for which Struers is renowned.
Duramin-150: Entry-Level Rockwell Hardness Tester
Load range: 3 –150 kgf
Duramin-100: Fully Automatic Micro/Macro/Universal Hardness Tester
Load ranges: 10 gf–62.5 kgf, 10 gf–150 kgf, 10 gf–250 kgf
Duramin-160: High-End Rockwell Hardness Tester
Load range: 1 –250 kgf
Duramin-600: Semi-Automatic Universal Hardness Tester
Load ranges: 1 – 250 kgf, 3 – 750 kgf, 5 – 3000 kgf
Duramin-650: Semi-Automatic and Fully Automatic Universal Hardness Tester
Load ranges: 1 – 250 kgf, 3 – 750 kgf, 5 – 3000 kgf
Check out our complete range of Duramin hardness testers.
DELVE DEEPER INTO HARDNESS TESTING
If you would like to know more about the hardness testing methods for metallic and other materials, including a full definition of hardness testing, the different applications of hardness tests and how to prepare for hardness tests, download our resources.
Find all you need to know about hardness testing
Download our Hardness Testing Application Note
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