A hardness tester is a measurement instrument that determines the strength and toughness of a material by applying an indentation force to its surface. Hardness tests are typically used in quality control applications to ensure that materials meet specific standards. The hardness of a material is determined by how much an indented sample resists deformation or fracture when subjected to a compression load, but the test can also be used to measure resistance to scratching or abrasion. The test is most often performed on metals but can be used on a variety of other materials including plastics, glass and ceramics.
A good hardness tester provides a reliable, repeatable measurement with a high level of accuracy. Typical features include a digital display, scale/selectable test force capabilities and automatic main test force loading and unloading. Some models offer a USB data storage capability for easy reporting and analysis. The best hardness testers are designed to be user-friendly, allowing for ease of use and error-free operation. This helps reduce operator fatigue and produces readings that engineers and manufacturers can trust.
Different types of hardness testing instruments are available, depending on the desired application and the type of material being tested. Some of the most common hardness tests include Brinell, Rockwell and Vickers. The Rockwell method is the most universal and uses a diamond cone to indent a workpiece’s surface and a steel ball to measure the depth of the impression. This test is most useful for verifying the correct heat treatment has been used on a part.
The Brinell method is a non-destructive test that measures the resistance of a material to indentation. A diamond pyramid is pressed into the test piece’s surface to leave an impression. This test can be difficult to perform on uneven surfaces and requires a high level of optical equipment, making it impractical for some materials. The Vickers and Knoop methods are both microhardness testing techniques that use a narrow diamond shaped indenter to produce an impression on the test piece. These tests are most useful on small parts, thin sections and case depth analysis.
Ultrasonic portable hardness testers utilize the acoustic measuring principle to enable a non-destructive and contactless test for a variety of metals, from soft to very hard. They are capable of testing a wide range of materials and surfaces including thin coatings and platings without damaging the surface. This type of portable hardness tester is often used for applications in aerospace, automotive and medical components as well as knife blade manufacturing.
A key feature of an ideal handheld hardness tester is a clear and concise digital display that allows for quick and simple interpretation. In addition to the digital display, an effective handheld hardness tester includes a user-friendly interface and a compact design to allow for easy handling. This helps to reduce operator fatigue, errors and time spent interpreting results. It also helps to increase productivity by reducing the time and effort it takes to complete each test.