Micro Hardness tester is an instrument for measuring a material’s hardness level from thin, microscopic to complex shapes. The purpose of hardness measurements is to determine a material’s resistance to deformation due to pressure.
The principle of hardness testing is to apply pressure to the surface of the object being tested, and then check the depth of deformation. Measurement by hardness testing is not only efficient, but has good accuracy.
The measurement results are consistent, and equipped with other important supporting features, making the hardness test widely trusted by professionals and technical experts. This hardness test has a variety of method options that you can choose according to your needs.
Difference Between a Micro Hardness Tester and a Macro Hardness
The main difference that you can tell from this hardness test is the test load. Micro hardness tests are usually used to test small loads. From test load, this micro test is designed for small, thin samples which are used to study microstructure transformations in a material.
Then macro hardness test which is aimed at general measurements. In terms of magnification, it can be seen that the micro hardness test requires high magnification to accurately measure the dimensions of small indentations. Unlike the macro hardness test, the hardness test does not require high magnification.
Types of Microhardness Testing Method
Discussing material hardness testing, there are at least 7 choices of methods that are often used, such as Rockweell, Vickers, Brinnel, Knoop, Shore, Webster, and Leeb. Below you will get an exposure to the different types of hardness testers and their scales, how they work.
1. Rockwell Method
The Rockwell test method has quite a lot of scale options so it can be used for many materials. The application of the Rockwell method is usually to evaluate the surface of thin films, test small components of medical devices, electronics and material research for development.
The principle of Micro Hardness Testing with the Rockwell method involves an indentation process, where there are 2 loads, namely the initial load (small load) which is used as a reference point and the main load, the size of which depends on the scale and test load.
The second principle of this test method is the process of measuring the penetration depth. In this measurement there are 2 stages, first measuring the depth of the indentation and calculating the elastic recovery to ensure the hardness value of the material.
The next principle that you must understand is regarding hardness calculation. With this test method you must understand the HR (Hardness Number) to calculate it.
The general formula for Rockwell Hardness is as follows.
HR = N – (d/s) ( where N is a constant that is based on the scale, d is the measured depth of indentation, and s is a scaling factor)
2. Vickers Method
This hardness measurement technique on a microscopic scale uses a pyramid-shaped indent with an angle of 136 degrees. The Vickers method can be used in many industrial sectors, research fields and as a teaching tool in the education sector. This is because the Vickers method is precise and accurate.
The principle of measuring the Vickers method can be known from the application of force (load) to the test material through a diamond indenter. When measuring horizontal and vertical distances, they must be within a 5% radius of each other.
The size of the indentation when measuring is obtained from the distance between the horizontal point and the vertical point.
Vickers hardness is calculated using the formula (HV), which is produced by dividing the test force applied (F in newtons N) by the surface area of the remaining. Calculation of the surface area of the pyramidal residual indentation, from the average of the two diagonals d1 and d2 (in mm).
3. Micro Brinell Hardness Test
Brinell hardness test is a method for measuring the hardness of a material based on the size of the indentation left by a steel ball or tungsten carbide when pressed with a certain load onto the surface of the material.
This microhardness test method is often chosen because it is simple and easy to use, making it suitable for laboratory and outdoor conditions. Not only that, this test is also suitable for soft materials.
The Brinell hardness value (HB) is calculated by dividing the applied load by the resulting indentation surface area.
Various Considerations for Select Microhardness Testing Method
Following are several factors that can be taken into consideration when choosing a microhardness test method
1. Material Type and Sample Thickness
The important point you need to know at the start is regarding the type of material. This relates to determining a suitable method, whether the material is hard or soft, and whether the type of material is heterogeneous or not. As well as the level of sample thickness
2. Indent Size
The next thing you need to pay attention to is the size of the indent. Indentation measurements are useful for knowing the need for precise measurements, so as to get more precise results.
3. Cost and Tools
Considering costs is certainly important, choosing a simpler method is more recommended for routine testing. Not only that, you also need to ensure the availability of the selected tools.
These are some information on various micro hardness tester techniques and crucial factors to take into account when selecting the best approach for your company or study. If you want to explore products like hardness testers and micro hardness testers, we recommend visiting WorldofTest.com, a global supplier of advanced testing instruments.
