I. What is the Static Hardness Test?
Sometimes the need to choose the right hardness test for materials can lead you to categorize the available hardness test methods based on their load application technique. A hardness test that applies the load using an indenter on the material’s surface to cause an indentation is often known as a static hardness test.
The indenter employed in these tests is often ball-shaped or pyramid-shaped diamond indenters. Additionally, these test methods are often the most popular hardness tests, including Vickers, Knoop, Rockwell, and Brinell hardness tests. The hardness of the material using these tests is dictated by the impact of the load on the material surface and the area of depression on the material on the removal of the load.
II. Applications of Static Hardness Test
Static hardness tests are often applied to stationary materials and test samples and adequately clamped on a support platform to restrict movements. These sample movements can significantly affect the accuracy of the results of these static tests. Also, the material samples have to be cut from the main material for the test and, as such, are often available in laboratories and testing facilities. This lack of portability makes them more suitable for the small-sized material hardness test.
Related Article: Principle and Applications of the Vickers Method
Related Article: Principle and Applications of the Brinell Method
III. What is the Dynamic Hardness Test?
Dynamic hardness test is the second category of hardness test based on the load application technique. It often measures a material’s hardness based on the rebound velocity of the load after its impact on the test material. Interestingly, the first dynamic hardness test came into the limelight in the early twentieth century using the Scleroscope to test material hardness. One example of this hardness test is the Leeb hardness test which uses a device equipped with a string-powered carbide ball hammer. The hammer is propelled by the spring and impacts the material surface. However, getting the hardness value requires the measurement of the rebound velocity after its impact.
IV. Applications of Dynamic Hardness Test
Due to its portability and unique load application, the dynamic hardness test is applied in various industries with specific use cases. Also, they are often preferred in sectors that require specific material parameters, including yield strength, elasticity modulus, and strain hardening coefficient. Their versatility also makes dynamic hardness testing a suitable method for testing various materials, including elastomers and varying hardness crystals.
V. What is the Difference between Static Testing and Dynamic Testing
The primary difference between static and dynamic testing is in their load application, where stationary loads apply in static testing, and a moving load applies in dynamic testing. Also, static loads often impact the material under gravity, which means they are only suitable for horizontal surfaces, unlike dynamic testing, which is able to measure the hardness of both horizontal and vertical surfaces. Additionally, there is often no consistency with the requirements for the indenters in static testing, which makes it difficult to compare data. The integration of electronics within dynamic testing devices and uniformity of the impacting devices makes it easy to share and compare test results and data.
In conclusion, static and dynamic hardness testing are the two categories of hardness testing based on the load application have their specific application. Also, these tests have differences that make them suitable for only these applications. But more importantly, you want to be sure that you are aware of these differences to take full advantage of these hardness testing methods when selecting the appropriate testing method when measuring your material hardness. Ultimately, you want to choose a proper testing method that ensures high accuracy.