The Rockwell Hardness Test isn’t about brute force, it’s about precision! It uses a special indenter with a diamond tip to measure the distance it indents into a material under different loads, where the deeper the indentation, the softer the material.
Hardness describes how well the material resists the load and the amount of permanent indentation caused. The Rockwell hardness test measures this resistance by capturing the permanent depth left behind by the indenter.
Block Type
RockwellSuperficial Rockwell
The Rockwell Hardness test offers a variety of methods to measure a material harness. There are over 12 different methods, each using specific loads and indenters to analyse diverse materials.
For most metals, the Rockwell hardness test is a reliable method, and it excels at testing how a metal resists the indentation under a controlled pressure. However, the Rockwell hardness test is not suitable for every situation. They include:
The Rockwell Hardness Test provides a range of methods to assess material strength. While it’s a great option for metals, understanding its limitations and choosing the right scale are essential for obtaining the most accurate results.
The Rockwell hardness test offers various scales, which are all designed with specific loads and indenter sizes tailored to different types of materials. These scales precisely measure hardness across a wide range of materials and thicknesses.
The key to obtaining the most accurate and reliable results is to select the Rockwell scale that best matches the characteristics of your material, including its hardness and thickness. To maintain accuracy and ensure consistency across different labs, the Rockwell test adheres to specific standards like ISO6508 and ASTM E18 for metals.
Testing the firmness of a material by carefully measuring how far an indenter sinks in under controlled pressure is the essence of the Rockwell Hardness Test. The steps are:
A: Preload
The Rockwell hardness test block is first submitted to an initial load using a predetermined weight, which is usually 3 kg for Superficial Rockwell methods and 10 kg for Rockwell methods. This preload ensures a consistent starting point for the test
B: Main Load
Once the preload is applied, an additional, larger force (known as the Main load) is applied to the indenter, pushing it further into the hardness test block. This force is usually kept for a predetermined amount of time (usually 7 seconds) to allow for material response, but it can vary based on the chosen Rockwell method being utilised.
C: Load removal
After the main load, the indenter returns to the initial preload setting, then the indentation depth can be measured.
D: Hardness Determination
The Rockwell Hardness number is obtained by converting the difference between the initial preload and the ultimate indentation depth. Remembering that Materials can sometimes slightly “bounce back” after the main load is removed.
The Rockwell Hardness Test offers a powerful and versatile approach to material analysis and testing. The different methods make it suitable for a wide range of materials, and its ease of use allows a quick and reliable testing.
Our Rockwell reference blocks are calibrated by our in-house UKAS/ISO accredited calibration laboratory and supplied with a UKAS Calibration or Manufacturers Certificate. Also supplied with corrosion prevention packaging and storage case. Listed values are nominal, actual block will be within the specified range of the nominal value.
If you require assistance at any point, our service hotline is available to support you.