Manufacturer and scientists normally go through the hardness test of any solid material to know the quality or identify the element.
The hardness gives an idea about the material’s characteristic behavior.
The material properties such as resistance, durability, strength, denting, etc. can be determined by doing the hardness test.
Otherwise, it is really hard to know whether the material will serve the purpose or not. Determine the testing method for the test is an important task. The type, size, and microstructure everything must be considered for that.
Choosing Hardness Test
For testing the hardness of metallic objects, there are a few methods, like the Rockwell hardness test, the Vickers hardness test, the Knoop hardness test, and the Brinell hardness test.
The Rockwell test is the most common and easiest method used in the industry. An indent is there which is inserted into the surface of the material by a major load and then the depth is measured. It is the quickest and most convenient one used for a larger sample.
The Vickers test also another one used for measuring the hardness of all types of solid materials. The diagonal lengths are measured to calculate the hardness of the sample. It is used for both the macro hardness testing and microhardness testing.
The Knoop test can be the alternative to the Vickers test. It is applicable to materials like ceramic which is brittle and hard as well. The hardness test is done in micro-level. The indenter that is used is a pyramidal diamond-shaped and asymmetric. It is suitable for small areas. It helps to test thin layer hardness like coating. The cracking problem can be solved by this.
The Brinell hardness test is for materials which have grain structure and are large in size.. Here a carbide ball is used to measure the hardness optically.
For minerals or rocks, the most common test is the Mohs hardness test. Here ten reference minerals with their hardness value are used to determine the hardness of that unknown element by scratching the outer surface. This is easier and simple.
For woods, the most common is the Janka test. Here, a small steel ball is inserted on the surface and the force is measured to know the hardness.
To get an accurate result, there are a few other factors which must be considered and controlled, like vibrations, temperature, light, humidity, temperature, etc. Also, follow the proper steps of how the test should be done. Choose a clean surface for the test.