Using a specified indenter and a defined load, a Rockwell hardness tester measures the depth of the indentation created on a material to determine its hardness. One of the most popular types of hardness testers in use today is this one. By applying a known force to the surface of a material, a hardened steel ball or diamond cone indenter is used to determine the material’s Rockwell hardness. The Rockwell hardness value is then determined by measuring the depth of the indentation. The harder the material is, the greater the Rockwell hardness number. Numerous industries, including aerospace, automotive, manufacturing, and construction, use Rockwell hardness testing. A wide variety of materials, including metals, alloys, plastics, and polymers, are tested for hardness using this method.

What Are the Rockwell Hardness Tester Parts?

To conduct precise hardness testing, it is imperative to comprehend how each part of the tester interacts with the others. Knowing the parts of the tester will help you locate the cause of a malfunction and take remedial action if it occurs. You can do routine maintenance procedures to make sure the tester stays accurate and dependable by being aware of the different parts and their duties. The three main parts of a Rockwell hardness tester are:

  • Indenter

A hardened steel ball or diamond cone is used as the indenter, which is pressed into the sample’s surface to create an indentation. The substance being examined and the level of accuracy required to determine the kind of indenter that is utilized.

  • Test force applicator

The indenter receives a known load from the test force applicator. Depending on the substance being tested and the necessary precision, the test force can be changed.

  • Measurement device

The measuring tool determines how deep the impression is. The Rockwell hardness value is then determined using the indentation’s depth.

560RSS Digital Double Rockwell Hardness Tester 1

What Is the Rockwell Hardness Tester Working Procedure?

Rockwell hardness testing is a precise procedure, and getting the right results depends on using the right steps. The sample is subjected to a substantial load by the Rockwell hardness tester, therefore applying the wrong technique can harm the sample. Given the strength of the Rockwell hardness tester, using it properly can help avoid mishaps. How to use a Rockwell hardness tester? The Rockwell hardness test procedure is as follows:

  1. Preparing the sample

The sample surface needs to be clean, flat, and smooth. It could be essential to scrape or polish the surface if it is not perfectly smooth. Additionally, the sample must be substantial enough to sustain the indentation without being harmed.

  • Selecting the correct test force and indenter

There are numerous test forces and indenter types available for the Rockwell hardness tester. The type of material being tested and the level of accuracy required will determine the appropriate test force and indenter.

  • Place the sample on the Rockwell hardness tester

The sample must be set up on the Rockwell hardness tester so that the indenter is parallel to the sample’s surface.

  • Apply the test force

The indenter should receive the test force for the appropriate number of seconds. You will find details on the test force duration in the Rockwell hardness test standard you are employing.

  • Measuring the indentation depth

The test force is released and the indentation depth is measured after the indentation has been held for the allotted amount of time. Using a dial gauge on a Rockwell hardness tester, the indentation depth is calculated.

  • Calculating the Rockwell hardness

The Rockwell hardness number is calculated using the following Rockwell hardness test formula:

Rockwell hardness number = 100 – d

where d is the indentation depth in millimeters.

560RSSZ Automatic Rockwell Hardness Tester 1

What Are the Factors That Affect the Accuracy of a Rockwell Hardness Test?

Because the Rockwell hardness test is so exact, even minor variations in the variables that affect it can cause considerable mistakes in the findings. When deciding if a material is safe and of high quality, the Rockwell hardness test is frequently employed as a key factor. The results of a Rockwell hardness test, for instance, may be used to determine whether a material is appropriate for a specific application. Inaccurate test results could result in the usage of inappropriate materials, which could have detrimental effects.

  • Surface preparation of the sample

To obtain an accurate reading, the sample’s surface needs to be flat and smooth. The indenter won’t leave an even indentation on a surface that is excessively rough.

  • Alignment of the indenter

It is necessary to orient the indenter parallel to the sample’s surface. The indentation will be slanted and the reading will be incorrect if the indenter is not properly aligned.

  • Test force duration

The right amount of time must be given to the test force application. The indentation won’t be deep enough and the reading won’t be correct if the test force is applied too quickly. The indentation will be too deep and the reading will be incorrect if the test force is applied for too long.

  • Measurement of the indentation depth

Accurate measurement of the indentation depth is necessary. The calculation of Rockwell hardness will be incorrect if the indentation depth is not determined precisely.

HR-150A Rockwell Hardness Tester 1


A versatile and precise tool for determining the hardness of a variety of materials is the Rockwell hardness tester. To get accurate findings, it’s crucial to comprehend the tester’s parts, how to use a hardness tester, and the variables that can compromise the test’s accuracy. It is challenging to use the tester appropriately and get reliable findings without understanding how it operates. Knowing how the tester operates will enable you to locate the issue’s root cause and take appropriate action to fix it.

You can execute routine maintenance procedures to make sure that the tester remains accurate and dependable by having a thorough understanding of how the tester functions and how the various parts interact with one another. It’s critical to take your individual needs into account when selecting a Rockwell hardness tester.

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