Universal Hardness Tester Brinell, Vickers, and Rockwell

Do you want to understand what hardness is, why it should be determined, and how does a hardness tester work? This blog is all about that.

Hardness Tester – Origins

Hardness (as opposed to softness) in materials science is a measure of a material’s ability to resist plastic deformation under external localized impact: indentation, scratching, or abrasion. In other words, a hard material has a greater ability to retain its shape under such external forces.

It is a well-known fact that diamond is the hardest material of natural origin. It is also clear that different materials have different hardnesses. Metals can be as hard as titanium and steel or as soft as copper, gold or lead. Wood is softer than glass, and rubber is softer than wood. But when it comes to comparing the hardness of different grades of steel, the wear resistance of different types of plastic, or the scratch resistance of different enamels, you do need to have clear values that can be compared to each other to choose the best material for creating consumer products. This is where the need for hardness measurement methods comes in.

Mohs Hardness Scale

The first attempt to define hardness through numerical values was made in the early XIX century. As a geologist and mineralogist, German scientist Friedrich Mohs ranked 10 selected minerals according to their ability to scratch each other. Thus, talk, as the softest of them, received a value of 1, and the hardest one, diamond, respectively, 10.

The differences in hardness between the individual grades of the scale are not the same. For example, the difference between grades 9 and 10 is significantly greater than between grades 1 and 9. Around 1900, further testing procedures were developed for technical purposes. In these procedures, hardness is not determined by scratching, but rather by pressing the material to be tested with very hard objects of a certain size and shape. which was the beginning of the widespread use of special hardness testers.

Although the Mohs test makes it easy to identify minerals in the field, it is not suitable for accurately measuring the hardness of industrial materials such as ceramics or steel. Other hardness scales, such as the Knoop’s scale, provide a more accurate measure.

The Essence of Hardness – Understanding the Definition

Various sources, from articles on the Internet to scientific publications, say that hardness is a characteristic of a material, but it is not its fundamental property. What does this mean?

The fundamental physical properties of materials are usually related to their chemical composition, molecular and crystal structure. For example, density, electrical conductivity, Young’s modulus (measuring the stiffness of a material), and Poisson’s ratio (characterizing its deformation response) are just a few examples of fundamental material properties. The values of such quantities do not depend on the method of their measurement. That is why they are fundamental. Hardness is not.

What’s wrong with hardness?

1. Hardness is not a fundamental property because it can depend not only on the composition of the material, but also on the treatment of its surface. Treatments such as grinding, polishing, heat treatment, or coating with special materials can make the surface more tough or scratch-resistant, reducing the tendency to wear. Such treatments can also change the appearance of the material, but do not affect its fundamental properties.

2. Another reason why hardness is not a fundamental property of a material is that it is impossible to establish a universal standard, reference method of measurement or a single type of hardness tester. Hardness is measured by a variety of methods that use their own specific scales. This will be discussed below.

3. Hardness is a manifestation of a set of mechanical properties. Hardness alone cannot fully describe the mechanical response of a material. Materials can have the same hardness but different strength, flexibility, toughness, etc. Also, mechanical properties are more complex and include tensile strength, impact strength, toughness under load, etc. In addition, hardness can depend on the scale of the test. For example, macroscopic hardness may differ from microscopic hardness.

With this in mind, it is important to understand that hardness is a measurable characteristic, not a property that is entirely determined by the intrinsic nature of the material. Molecular structure, chemical composition, and crystal lattice are all fundamental aspects that influence hardness, but they are not the only ones. The main thing is that the hardness value can vary depending on the measurement method, so it is not a property, but only a certain technical characteristic.

Not surprisingly, there are three types of hardness: scratch hardness, rebound hardness, and indentation hardness.

Scratch Hardness Test

This is a test of how resistant a sample is to fracture or permanent plastic deformation due to friction against a sharper object that scratches the sample. The examination is performed using special tools, hardness testers. The Martens method uses a diamond cone with a 90° apex angle. The test force is varied to achieve a scratch width of 10 µm, which is measured under a microscope. This way, a specific scratch resistance value can be assigned to the sample and the resulting scratch hardness value can be placed on a comparative Mohs scale. When testing coatings for scratch resistance, the force required to cut through the film down to the substrate is determined.

One such hardness tester, a device called a “sclerometer”, which takes a microscopic measurement of the width of a scratch produced by a diamond under a fixed load and under fixed conditions.

Rebound Hardness Test

Rebound hardness, also known as dynamic hardness, is a test that refers to the elasticity of a material, i.e. its ability to absorb impact energy. In dynamic hardness testing procedures, an indenter is struck against the surface of a specimen. The material of the specimen can deform elastically or inelastically. The deformation caused by the kinetic energy of the indenter can be measured.

In the drop hardness tester (a), an object of a certain mass is dropped freely on the specimen with an indenter (ball), creating an indentation. In the impact hardness tester (b), the ball is placed on the surface of the specimen and an object of known mass is struck by a hammer or spring force and penetrates the indenter. The indentation is measured and a hardness value is assigned by comparison with a standard sample of known hardness.

In the classical dynamic hardness measurement technique, the height or rebound angle of a diamond-tipped hammer dropped from a fixed height on the material is determined. This type of hardness is related to elasticity.

In materials with a low deformation potential, such as rubber, the indenter that comes into contact with the surface of the sample springs back. The rebound angle is used to determine the rebound energy and to infer the hardness value.

Modern procedures actually work on slightly different principles, determining the Shore hardness value.

The most advanced hardness testers measuring in measuring Shore scale are supplied by NextGen:

• Digi Test II;
• NX-01 Shore Durometer.

Indentation Hardness Test

In this approach, hardness is measured through the deformation of a material due to static loading by a sharp object. In such hardness testers the results are based on measuring the amount of deformation caused by an indenter of a certain size under a certain load. These conditions determine the measurement result according to generally accepted standard scales, which include, but are not limited to, the Shore, Brinell, Vickers, and Rockwell scales.

The working principals of an indention hardness tester. So an indenter attached to the lower end of the press is forced into the surface of the sample with a certain amount of force and then pulled back. The indentation created can then be measured. The shape and size of the indenter are crucial for indentation resistance. With ball indenters, the sample material is pushed sideways and downward due to the plastic and elastic deformation of the material. Angled or needle indenters can cause cracking and flaking (e.g. for ceramics) in addition to deformation. The penetration rate also affects the behavior of the material under test.

For these reasons, guidelines for hardness test procedures, including hardness tester design, indenter, penetration rate, and optical evaluation system, are of particular importance. The most widespread are the hardness testers currently used, working according to the methods Brinell, Vickers, and Rockwell. They will be discussed further.

Brinell Test

The first indentation method of static hardness testing was introduced at the 1900 Paris World’s Fair by Swedish researcher J.A. Brinell. A Brinell hardness tester uses hardened steel or tungsten carbide balls with a diameter of 1, 2, 2.5, 5 or 10 mm as an indenter. This method uses a ball to press into the smooth surface of the sample with a certain amount of force. To obtain reproducible results, it is important that the sample is supported by a rigid support and that the indenter touches the sample without shaking or jolting. The test force is then increased to the specified maximum level at a specified rate and held for 10-15 seconds. The duration of the load in the Brinell test can vary depending on the material and is up to 180 seconds in the case of non-ferrous metals. If the duration is outside the specified range, the result may not be reproducible. The hardness is determined by the size of the indentation obtained.

Vickers Hardness Test

The Vickers test was developed in the 20s of the XX century by Robert L. Smith and George E. Sandland, who worked for Vickers Ltd. The method uses an indenter tip that is a regular tetrahedral diamond pyramid. This alternative to the Brinell test for measuring the hardness of materials facilitates the measurement because the necessary calculations are independent of the indenter size and it can be used for all materials regardless of hardness. The basic principle of Vickers hardness tester, as with all common hardness measures, is to observe the ability of a material to resist plastic deformation from a standard source. The Vickers test has one of the widest scales among hardness tests. The unit of hardness determined by the test is known as the Diamond Pyramid Hardness (DPH) or Vickers Pyramid Number (HV). The hardness number can be converted to pascal units, but there is confusion here with pressure units, which are also measured in pascals. The hardness number is determined by the load on the surface area of the indentation, not the area perpendicular to the force vector, and therefore it is not really pressure.

Rockwell Test

This test procedure was also introduced in the 1920s. The Rockwell test differs from the two previous approaches described in that it simply measures the depth of penetration of the indenter under a light load (preload) with the depth of penetration under the main load (heavy load). This simplification allows the Rockwell hardness (HR) value to be read from the tester immediately after the main force is removed. In contrast to the Brinell procedure, the Rockwell hardness tester uses simpler measuring machines that do not need to include optical measuring modules. For these reasons, the Rockwell test was quickly adopted and is now widely used primarily for simple and rapid quality control in production.

Hardness Comparison and Conversion

Measuring the hardness of materials on different scales is challenging. Due to the use of different methods, procedures, and parameters, it is difficult or impossible to compare the results. Different hardness testers use different measuring scales, such as Vickers, Rockwell, Brinell, Knoop, and others, they have different ways of loading and measuring the effects of this loading, and each scale has its own measurement range.

Converting results from one scale to another can be a tricky task, as hardness measurement is not a simple conversion of one unit to another. Due to the unique properties of each scale, an accurate conversion can only be guaranteed for a limited set of data obtained under specific conditions.

In addition, the use of hardness scale types may vary from region to region of the world, depending on the country. For example, in the United States, the Rockwell scale is widely used, in Europe both the Rockwell and Vickers scales are frequent, and in Japan some cases are measured using the Brinell scale. Each country has national standards and guidelines for measuring the hardness of materials. This creates certain problems for manufacturers of consumer goods because they have to buy a bunch of different hardness testers, do additional quality control to meet the reglementations put forward by the importing countries.

Organizations such as ASTM International (American Society for Testing and Materials) and CEN (European Committee for Standardization) also develop and publish standards related to hardness measurement that can be used in accordance with regional requirements.

Hardness Tester ISO

At the global level, there are international organizations such as the International Organization for Standardization (ISO) that set standards and guidelines for hardness measurement. They define hardness measurement methods, test conditions, and inspection procedures. For example, ISO 6507 specifies the method of measuring microhardness using the Vickers scale, and ISO 6508 specifies the method of measuring hardness using the Rockwell hardness testers.

Standardization in this area helps to ensure that hardness measurement results are commensurate and comparable between different laboratories and countries. It also helps to establish international guidelines for hardness measurement and to ensure the quality and reliability of measuring equipment.

These differences in methods and standards pose challenges, especially for companies operating internationally. Some comparisons can be made using conversion tables or calculators, but this may not always be the ideal solution for the reasons mentioned above.

“If only there was a machine that could measure hardness according to all common standards… It would be a perfect universal hardness tester!” – manufacturers dreamed. And our company NextGen introduced its solution to the market – UniGen!

UniGen Hardness Tester by NextGen

UniGen is a universal hardness tester that provides all-in-one hardness measurement. The device is specifically designed to offer industry-leading ease of use, reliability, and accurate results for Vickers, Rockwell, and Brinell hardness measurements. This instrument is everything you need to get your hardness testing work done across multiple standards. Like all other NextGen equipment, the UniGen is industry certified, easy to use, operated via a touchscreen display, has an intuitive interface, and comes with a full set of consumables to get you started.

If you’re tired of searching for ways to measure hardness according to this  and that standard, UniGen will provide you with a turnkey solution to universalize your testing facilities and free up a lot of time for the really important things.

More on this topic

Keep Reading in Rockwell Hardness Testers

See the Rockwell Hardness Testers range

Rockwell Hardness Testers28 Sep 2026The Rockwell Scale Explained: How to Choose Between HRC, HRB and Superficial ScalesA Rockwell hardness number tells you very little until you know the letters that come with it. A reading of 60 on one scale and a reading of 60 on another describe different materials, tested with a different indenter under a different force, and neither can be compared with the other until someone knows which scale produced it. A drawing that asks for 60 HRC is specifying a whole test: a diamond indenter, a total force of 150 kgf and a depth measurement made in a defined way. ASTM defines thirty Rockwell scales. Picking the right one is a decision that can go wrong without any warning, because the wrong scale does not produce an error message. It produces a number, and that number looks just as plausible as a valid one. This article explains what...Read the articleVickers and Knoop Hardness Testers10 Sep 2026How to Measure Case Depth: Effective Depth, Total Depth and the Hardness Limit That Decides ItA drawing asks for case depth in a single number, and that number carries a tolerance, an acceptance decision and sometimes a rejected heat lot. What the drawing rarely says is which of two different depths it means, or which hardness value marks the boundary. Two laboratories can follow the same procedure on the same part, measure carefully, and report depths that differ by a noticeable margin, because they drew the line in different places. The measurement itself is not the hard part. Agreeing on what is being measured is. This article is about the traverse: how case depth is defined, what fixes the boundary, and what the work demands from the equipment that produces it. If you are still deciding whether microhardness is the right method at all,...Read the articleVickers and Knoop Hardness Testers18 Oct 2025Macrohardness vs. Microhardness Testing: What They Are and How They WorkIf you've worked with hardness testing, you've likely come across the terms "microhardness" and "macrohardness." They show up in datasheets, testing specs, and lab reports. Still, it's not always clear what separates the two — or when one is better than the other. Both belong to a broader category known as indentation hardness testing, a method used to assess how materials respond to pressure from a sharp or rounded object. Microhardness and macrohardness approaches were developed to deal with very different scales and sample types, from polished coatings to structural steel. At first glance, the difference seems simple. But there's more to it than load size or indent depth. This article breaks down what micro- and macrohardness testing actually...Read the articleMetal Testing4 Nov 2026Torsion Testing of Metals to ASTM E143 and ISO 7800: Shear Modulus, Wire Torsion and Machine SetupA tensile test pulls a specimen. A torsion test twists it, which is the loading a drive shaft, a helical spring, a fastener or a wire in a rope actually sees. Under one name, torsion testing of metals covers two different jobs. One is an elastic measurement: the shear modulus G of a bar or tube, from a few degrees of twist under ASTM E143. The other runs to destruction: wire twisted one way under ISO 7800 until it breaks, the result counted in whole turns. Both run on a torsion testing machine with one grip that turns and one that holds, yet a setup that gives a good turn count can still give a poor modulus. This guide covers the mechanics, both standards, the fracture and the setup details that decide the number. Short answerWhat does a torsion...Read the articleMetal Testing25 Oct 2026How to Perform a Tensile Test on Metals: Step by Step to ASTM E8/E8M and ISO 6892-1A tensile test looks simple from across the laboratory. A specimen goes into the grips, the crosshead moves, the specimen stretches and breaks, and the software prints a few numbers. Most of what decides whether those numbers are right happens before the first newton of force: how the specimen was machined and measured, where the gauge marks sit, how the specimen hangs in the grips, which extensometer is on it and how fast the machine is told to pull. This guide walks through a room-temperature tensile test on metal in the order a laboratory performs it, following the two standards most reports are written against, ASTM E8/E8M and ISO 6892-1. Where the two differ, it says so, because a result is only comparable with another result obtained under the...Read the articleMetal Testing18 Sep 2026Gauge Length Marking and What It Does to Your Elongation ResultRecorded during the pull. Elongation is the one tensile property that is not measured during the test. Force and extension are captured while the machine is pulling, but elongation after fracture is worked out afterwards, on a bench, from two pieces of broken metal and a pair of marks that somebody applied before the test started. Everything that was careless about those marks arrives, unchanged, in the final report. That makes gauge marking a measurement step rather than a preparation chore. It is also the step most likely to be done differently by two operators in the same laboratory, on the same shift, using the same standard. Short answerHow does gauge marking affect the elongation result?Elongation after fracture is worked out from marks...Read the articleMetal Testing5 Aug 2026Vicat Testing and What Cement Setting Time Really Tells YouVicat setting time is a standardized cement paste measurement used for specification compliance and quality control. It identifies when a paste prepared under defined conditions reaches the initial and final set criteria of the selected method. It does not directly predict concrete haul time, cold joint formation, finishing time or field workability, because those depend on the complete mixture: water content, admixtures, aggregates and temperature. This guide covers what Vicat setting time measures, how the apparatus produces the number, which test conditions make results drift, and what separates a manual instrument from an automatic one. Setting Time Is Not Early Strength Initial and final set describe the stiffening of a standardized cement...Read the articleMetal Testing2 Aug 2026Universal Testing Machine Software and What It Has to DoTwo laboratories can test comparable material on similar frames and still report different yield results if they use different control modes, strain inputs or calculation rules. Those differences can originate in the software layer rather than in the frame itself. That is why universal testing machine software deserves the same scrutiny as the force and strain measurement systems. This guide follows the software workflow from method definition and machine control through calculations, reporting and traceability. Short answerWhat does universal testing machine software have to do?It has to run the test the standard describes and leave a result that can be traced. That means controlling displacement, force or strain at the rates the method sets,...Read the articleMetal Testing20 Jul 2026Flexural (Bend) Testing Explained: 3-Point vs 4-Point, Standards, and SetupFlexural (bend) testing explained: what it measures, three-point vs four-point setups, the standards for plastics, metals, composites and concrete, and how to choose the right fixtures and...Read the article

Related equipment

Machines Behind This Article

Universal Tester For Vickers / Knoop, Rockwell and BrinellUniGen – Universal Hardness Tester (Rockwell, Vickers, Brinell)UniGen is an all-in-one universal hardness testing system for Rockwell, Vickers, Knoop, and Brinell measurements. Built for accurate, repeatable hardness testing,...View productBrinell Hardness TestersBrinGen 3000 Series – Digital and Automatic Brinell Hardness TesterBrinGen 3000 Series is a digital Brinell hardness tester for evaluating indentation resistance in metals such as cast iron, unquenched steel, non-ferrous metals,...View productRockwell Hardness TestersNG-RockGen Analogue Series – Rockwell Hardness TesterNG-RockGen Analogue Series is a Rockwell hardness tester for routine hardness measurement of metals, available in manual and electronic models. It supports HRA,...View productRockwell Hardness TestersNG-RockGen DGEN Series – Digital Rockwell Hardness TesterNG-RockGen DGEN Series is a digital Rockwell hardness tester for measuring metal hardness by indentation depth under standard Rockwell loading. Available in...View productRockwell Hardness TestersGenRock NG-150 Series – Rockwell Hardness TesterGenRock NG-150 Series is an advanced Rockwell hardness tester for regular and superficial hardness testing of metals and alloys. Available in manual and automatic...View productVickers and Knoop Hardness TestersMicro Vickers and Knoop Hardness TesterThe NG-1000 Micro Vickers and Knoop Hardness Tester is designed for accurate microhardness testing with digital, standard, and CCD optical-analysis configurations....View productVickers and Knoop Hardness TestersMacro Vickers Hardness TesterNG-5000 Series Macro Vickers Hardness Tester is built for accurate macrohardness measurement with standard digital, digital, and CCD optical-analysis...View productPortable Hardness TestersTelebrineller – Portable Brinell Hardness Testing SystemNextGen Telebrineller is a portable Brinell hardness testing system for field use, welding crews, and QA teams that need fast BHN checks outside a stationary lab....View productBrinell Hardness TestersBrinGen Scope – CCD Brinell Measuring ScopeBrinGen Scope is an advanced CCD Brinell measuring scope for manual or digital Brinell hardness testing systems. Designed to work with a computer or laptop, it...View productRockwell Hardness TestersHardness Test Blocks, Indenters and AccessoriesHardness test blocks, indenters, and accessories support daily verification and reliable operation of metal hardness testing systems. The range includes certified...View product