Do you know three common hardness testers?
Are you in the market for a hardness testing machine?
Knowing the types, similarities, and differences in the kinds of hardness machines available will give you a better platform to make an informed and better decision.
Here are the three types of the most sought-after hardness testing machines you will find around today.
Rockwell hardness tester
Rockwell hardness tester is the most popular hardness testing machine that is available in the industry. This widespread use is linked to its accuracy and ability to carry out a hardness test quickly and easily using the Rockwell hardness tester.
It employs an indentation technique in measuring the hardness of sample material using an applied load force to cause the indentation.
Application of Rockwell hardness testing machine includes in the testing of metals,
Vickers hardness tester
Vickers testers are the preferred technique for testing for microhardness testing, which makes it most suitable for small materials like thin foils, light metals, and ceramics.
The indentation method uses a pyramid diamond indenter with a square base and a range of applied load force between 10 grams to 1000 grams. However, you can use Vickers testers for macro hardness tests with an applicable load as high as 30,000 grams or even higher.
Furthermore, the material sample’s surface must be polished and smooth so that it does not result in an inaccurate result.
The Brinell hardness tester.
Brinell hardness tester uses a form of optical technique and instrumentation to carry out its hardness testing. The machine comes fitted with a special microscope for assessing the indentation made by a predetermined load.
This programmed load is often applied to the sample material. The indentation made is measured twice, with both measurements acting at right angles to each other.
The Brinell tester is equally suitable for steel as well as non-ferrous metals and cast iron.
What is the difference between them?
Several differences exist for the different types of hardness tests. These differences are why one hardness testing machine is better suitable for a particular material than other hardness testing techniques.
The load range for each testing machine is different. You have the Vickers having the lowest applied load to the Brinell having the highest applied load. However, the Rockwell hardness tester can vary from very small load to medium to large testing loads.
One other difference is the material thickness measured by each hardness tester. The Vickers tester measures thin and small samples. The Rockwell hardness tester can measure medium to large objects, and the Brinell hardness measures large materials.
The material surface determines the most suitable tester for any sample material. The Vickers tester is ideal for a smooth surface. On the other hand, the Brinell tester is used for coarse and abrasive surfaces. The Rockwell hardness tester is used for smooth to moderately rough surfaces.
The scale used by the hardness testers is also different, and there is a need for conversion after the indentation measurements. Rockwell hardness tester has the easiest and fastest readability. In contrast, the Vickers and the Brinell testers are slow to read and require an indexed hardness table for conversion.
The Brinell and Vickers hardness testers employ optical systems for measuring indention on the objects. In contrast, the Rockwell hardness tester does not require any microscope to check indentation, making it faster.
Finally, careful consideration of the functions available for each hardness testing machine is needed to ascertain the most suitable machine for your individual need.
As enumerated above, increased functionality like the accuracy of measurement and the testers’ automation level will reflect on their overall cost. Hence your budget will also be an important factor in choosing the most suitable tester for you.
While there are advanced technologies in the recent hardness testing machines available in the market, your choice will be affected by your material’s size and location. Where on-site hardness testing is required, or where the material is too large to carry around, the hardness testing machine’s portability becomes critical. Overall, you will want a versatile hardness testing machine to test both small and large materials even if the surfaces are rough or smooth. Also, a hardness testing machine that can test different materials, including ferrous and non-ferrous metals, and hard plastics, ceramics, and cast iron, should be most beneficial.