Top 10 Hardness Tester Brand & Manufacturers

What is a Hardness Tester

A hardness tester is a specialized device employed to measure the hardness of materials. Hardness, in materials science, refers to a material's resistance to various types of permanent deformation, such as indentation, scratching, or abrasion. By quantifying this property, hardness testers help in understanding a material's mechanical characteristics, which is crucial for material selection, quality control, and product design across numerous industries.

History of Hardness Tester

• Early Beginnings: The concept of hardness testing dates back centuries. In the 18th century, simple methods like scratching one material against another were used to compare relative hardness. For instance, in mineralogy, the Mohs scale was developed in 1812 by Friedrich Mohs. It ranks minerals from 1 (softest, like talc) to 10 (hardest, diamond) based on their ability to scratch one another. This was one of the first systematic approaches to hardness measurement.
• Industrial Revolution and Metal Testing: With the rise of the Industrial Revolution in the 19th century, the need for more accurate hardness testing of metals became apparent. In 1899, Johan August Brinell introduced the Brinell hardness test. This method involved pressing a hardened steel ball into a metal surface under a specified load and measuring the diameter of the resulting indentation. It was a significant step forward in quantifying metal hardness.
• 20th - Century Innovations: In 1919, the Rockwell hardness test was developed. It offered a quicker and more convenient way to measure hardness, especially for different types of metals. The Rockwell tester used different indenter - load combinations, allowing for a wide range of hardness measurements. Around the same time, in 1921, the Vickers hardness test was introduced. It utilized a diamond pyramid indenter, providing more accurate results, especially for harder materials and thin sections.
• Modern Developments: In recent decades, with the advent of digital technology and advanced materials, hardness testers have become more accurate, portable, and versatile. Micro - hardness testers can measure the hardness of very small areas, while portable hardness testers, such as the Leeb hardness tester, allow for on - site measurements in various industrial settings.

Purpose of Hardness Tester

• Quality Control in Manufacturing: In manufacturing industries, hardness testers are used to ensure that raw materials and finished products meet the required hardness specifications. For example, in the automotive industry, the hardness of engine components like crankshafts and gears is crucial for their performance and durability. By regularly testing the hardness, manufacturers can detect any variations in the material quality and take corrective actions.
• Material Selection: When choosing materials for a particular application, hardness is an important factor. A hardness tester helps engineers and designers determine which material is most suitable. For instance, in construction, the hardness of steel used in building structures needs to be carefully considered to ensure the safety and stability of the building.
• Research and Development: In materials research, hardness testers are used to study the effects of different manufacturing processes, heat treatments, and alloy compositions on a material's hardness. This information is used to develop new materials with improved properties.
• Failure Analysis: In cases of product failure, hardness testing can provide valuable insights. By measuring the hardness of the failed component, engineers can determine if the material was properly processed or if it was subjected to excessive stress during use.

Principle of Hardness Tester

• Indentation - based Hardness Testing:
  • Brinell Hardness Test: A hardened steel or carbide ball of a known diameter ((D)) is forced into the material surface under a specified load ((F)). After removing the load, the diameter ((d)) of the resulting indentation is measured. The Brinell hardness number ((HB)) is calculated as (HB=frac{2F}{pi D(D - sqrt{D^{2}-d^{2}})}). The larger the indentation for a given load, the lower the Brinell hardness value.
  • Rockwell Hardness Test: There are different Rockwell scales, each with a specific indenter (a steel ball or a diamond cone) and load combination. First, a minor load ((F_0)) is applied, and the depth of penetration ((h_0)) is measured. Then, a major load ((F_1)) is added, and the new depth of penetration ((h_1)) is measured. The Rockwell hardness number ((HR)) is calculated based on the difference in penetration depths ((h_1 - h_0)) and is displayed on a dial or digital readout. Different scales, like HRA, HRB, and HRC, are used for different material hardness ranges.[!--empirenews.page--]
  • Vickers Hardness Test: A square - based diamond pyramid indenter with an apex angle of 136° is used. A known load ((F)) is applied to the material surface, and after removal of the load, the lengths of the diagonals ((d_1) and (d_2)) of the square indentation are measured. The Vickers hardness number ((HV)) is calculated as (HV = 1.8544frac{F}{d^{2}}), where (d=frac{d_1 + d_2}{2}). Vickers hardness is suitable for a wide range of materials and is often used for micro - hardness testing.
• Rebound - based Hardness Testing (Leeb Hardness Test): A small impact body is dropped onto the material surface from a fixed height. The impact body rebounds, and the Leeb hardness value ((HL)) is calculated as the ratio of the rebound velocity ((v_1)) to the impact velocity ((v_0)) of the impact body, i.e., (HL=frac{v_1}{v_0}times1000). The harder the material, the higher the rebound velocity and thus the higher the Leeb hardness value.
• Scratch - based Hardness Testing: A sharp indenter is drawn across the material surface under a controlled force. The resistance of the material to being scratched is measured. This method is often used for evaluating the hardness of coatings and thin films. The scratch hardness can be related to the force required to cause a certain level of damage to the surface.

Features of Hardness Tester

• High Accuracy: Modern hardness testers can provide highly accurate measurements, with some instruments capable of measuring hardness to within a fraction of a hardness unit. This accuracy is crucial for industries where tight material specifications are required.
• Wide Range of Measurement: They can measure a broad range of hardness values, from very soft materials like plastics and rubbers to extremely hard materials such as hardened steels and ceramics. Different types of hardness testers and scales are available to cover this wide range.
• Portability: Many hardness testers are now portable, allowing for on - site measurements in factories, construction sites, or in the field. Portable hardness testers are often battery - operated and lightweight, making them convenient for use in various locations.
• Digital Display and Data Logging: Most modern hardness testers feature digital displays, which provide clear and easy - to - read hardness values. Additionally, some models can log data, allowing for the recording and analysis of multiple hardness measurements over time. This is useful for quality control and research applications.
• Versatility: Hardness testers can be used on a variety of materials, including metals, plastics, ceramics, composites, and even biological materials in some cases. They can also be used to test different shapes and sizes of specimens, from small components to large structural parts.

Types of Hardness Tester

• Brinell Hardness Tester: Ideal for testing materials with coarse - grained structures, such as castings and forgings. It is also suitable for measuring the hardness of relatively soft metals. The large indentation made by the Brinell test provides an average hardness value over a relatively large area of the material.
• Rockwell Hardness Tester: One of the most widely used types, suitable for a broad range of metals. The different Rockwell scales make it adaptable to various hardness levels. For example, the HRC scale is commonly used for hardened steels, while the HRB scale is used for softer metals like aluminum alloys.
• Vickers Hardness Tester: Well - suited for testing hard materials, thin sheets, and for performing micro - hardness tests. The diamond pyramid indenter of the Vickers tester can produce small, precise indentations, making it ideal for measuring the hardness of small features or in cases where a more accurate measurement is required.
• Shore Hardness Tester: Primarily used for measuring the hardness of elastomers (rubbers) and plastics. There are different Shore scales, such as Shore A for softer rubbers and Shore D for harder plastics. The Shore hardness tester measures the resistance of the material to indentation by a spring - loaded indenter.
• Leeb Hardness Tester: A portable and non - destructive hardness tester. It is suitable for testing ferrous and non - ferrous metals, as well as some non - metallic materials. The Leeb tester is often used for on - site measurements where traditional indentation - based testers may be inconvenient.
• Micro - Hardness Tester: Designed to measure the hardness of very small areas, typically in the micron range. Micro - hardness testers are used in research and development, especially for studying the hardness of individual grains in a material, or for testing the hardness of small components like micro - electronic devices.
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• Scratch Hardness Tester: As the name implies, it is used to measure the scratch resistance of materials, particularly coatings, paints, and thin films. The tester can provide information about the material's ability to withstand abrasive forces.

Precautions for using Hardness Tester

• Specimen Preparation: The surface of the specimen to be tested must be flat, smooth, and free of any contaminants such as oil, dirt, or oxide layers. Rough or contaminated surfaces can lead to inaccurate hardness measurements. For some tests, the specimen may also need to be a certain thickness to ensure accurate results.
• Indenter Selection and Maintenance: The indenter is a critical part of the hardness tester. For indentation - based testers, the indenter should be of the correct type, size, and in good condition. A worn or damaged indenter can cause inaccurate indentations and incorrect hardness readings. Regular inspection and replacement of the indenter, as per the manufacturer's instructions, are essential.
• Load Application and Control: The load applied during the hardness test must be accurate and consistent. Inaccurate load application can lead to incorrect hardness values. Some hardness testers have built - in load - control mechanisms, but it is important to ensure that these are properly calibrated and functioning correctly.
• Testing Environment: The testing environment can affect the results. Extreme temperatures, humidity, and vibrations can influence the performance of the hardness tester and the properties of the specimen. Whenever possible, the test should be conducted in a controlled environment to ensure accurate and reliable results.
• Interpretation of Results: Different hardness scales are not directly comparable. It is important to understand the specific hardness scale being used and to interpret the results correctly. Additionally, the hardness of a material can vary depending on factors such as its microstructure, heat treatment, and the direction of testing. Multiple measurements at different locations on the specimen may be necessary to obtain a representative hardness value.

Things to consider when purchasing Hardness Tester

• Application Requirements: Determine the specific materials you will be testing and the hardness range of those materials. For example, if you mainly work with soft plastics, a Shore hardness tester would be more appropriate. If you deal with a wide range of metals, a Rockwell or Vickers hardness tester with multiple scales might be a better choice.
• Accuracy and Precision: Consider the level of accuracy and precision required for your applications. If you need to measure hardness to a very high degree of accuracy, look for testers with high - precision sensors and calibration capabilities. However, keep in mind that higher accuracy often comes at a higher cost.
• Portability: If you need to perform on - site measurements, portability is a crucial factor. Look for portable hardness testers that are lightweight, battery - powered, and easy to carry. Some portable testers also come with protective cases for added durability.
• Data Logging and Connectivity: If you need to record and analyze multiple hardness measurements, consider testers with data - logging capabilities. Some testers can also be connected to a computer or other devices for further data analysis. This feature can be useful for quality control and research applications.
• Brand and Reputation: Choose a hardness tester from a reputable brand with a history of producing high - quality instruments. A well - known brand is more likely to provide reliable products, good after - sales service, and technical support. Read reviews and consult with other users to get an idea of the brand's reputation.
• Cost - effectiveness: Set a budget for your hardness tester purchase. Compare the features and prices of different models to find the one that offers the best value for money. Consider not only the initial purchase price but also the cost of consumables (such as indenters), maintenance, and calibration over time.

Terms of Hardness Tester

• Hardness Scale: A system used to quantify the hardness of materials. Examples include the Brinell (HB), Rockwell (HR), Vickers (HV), Shore (HS), and Leeb (HL) scales. Each scale has its own method of measurement and is suitable for different types of materials and hardness ranges.
• Indentation: The depression or mark left on the material surface after applying a load with an indenter. The size, shape, and depth of the indentation are used to calculate the hardness value in indentation - based hardness tests.
• Load: The force applied to the indenter during a hardness test. The load value is an important parameter in calculating the hardness number, and different hardness tests use different load values depending on the scale and the material being tested.[!--empirenews.page--]
• Indenter: The tool used to create the indentation on the material surface. Indenters can be made of different materials, such as hardened steel balls, diamond pyramids, or cones, and their shape and size can vary depending on the hardness test being performed.
• Rebound: In rebound - based hardness tests (like the Leeb hardness test), the rebound is the bounce - back of the impact body after hitting the material surface. The height or velocity of the rebound is used to calculate the hardness value.
• Micro - hardness: The hardness of a very small area of a material, typically measured in the micron - scale. Micro - hardness testing is often used to study the properties of individual grains, phases, or small components within a material.
• Scratch Resistance: The ability of a material to resist being scratched by another material or a sharp object. Scratch - based hardness tests are used to measure this property, which is important for applications where surface integrity is crucial, such as in coatings and finishes.