I. What is Vickers Hardness?
Vickers hardness test is a method of measuring the hardness of materials by using a Vickers indenter and a test sample material. The Vickers hardness test, which is relatively easier than other methods, can be used for microhardness and microhardness testing. This method uses a conical-shaped diamond indenter and a specified load to measure the hardness of a material. This method can be used to compare the hardness values between different materials such as ferrous and non-ferrous metals, metal alloys, ceramics and composite materials.
II. Advantages and Disadvantages of Vickers Hardness
- The Vickers hardness test covers all hardness ranges; hence you can use this method to test various materials, from soft to hard ones.
- Only one type of indenter is used to perform all Vickers tests; a conical-shaped diamond indenter.
- Since the indents caused by Vickers test method are small, the test sample can be used for other applications after testing.
- The surface of the test sample should be well prepared and polished or ground for accurate measurements.
- As this method uses an optical measurement method, the tester should have a microscope making it more expensive.
- This method is time consuming as a test cycle takes 30 to 60 seconds, excluding the time taken to prepare the test sample.
Related Article: What are the Advantages and Disadvantages of the Vickers Method?
III. What is Brinell Hardness?
Brinell hardness test is a method similar to the Vickers hardness test, and Johan August Brinell developed it. This method was the standard hardness test used for machine manufacturing and engineering materials. The Brinell hardness test, which is relatively slower than other methods, can be used for microhardness and microhardness testing. This method can be used to test materials that have coarse or inhomogeneous surfaces that other methods cannot be used. Brinell hardness test uses a steel or tungsten indenter of a specified size and a specified load to make an indent on the test sample.
IV. Advantages and Disadvantages of Brinell Hardness
- The Brinell method does not require the test sample to be prepared for inspection. This method can be used to test materials with irregular surfaces.
- This method is suitable for testing materials made from cast metallurgy, such as cast steel.
- This method can use heavy loads to inspect the test sample, therefore suitable for testing hard materials.
- The Brinell hardness test causes a very large indent on the test sample; therefore, it’s not suitable for testing small materials.
- When testing very hard materials, the ball indenter can deform, making the measurements inaccurate.
- This method causes a deep penetration on the test sample hence not suitable for testing thin materials.
- This method can only be used to test samples with a flat surface.
- The method is time consuming and takes longer compared to other methods.
Related Article: What are the Advantages and Disadvantages of the Brinell Method?
V. What is the Main Advantage of Vickers Hardness Test over Brinell Hardness Test?
The Vickers hardness test uses a diamond indenter which does not deform easily even under high loads, while the Brinell hardness test uses a steel ball or tungsten carbide ball as an indenter. The indenter used in the Brinell hardness test can deform under heavy loads making the measurements taken inaccurate. Although both methods use an optical method of taking measurements, this makes the Vickers hardness test more accurate and dependable compared to the Brinell test.
VI. Why is Vickers Hardness Preferred?
The Vickers hardness test method is preferred because of its accuracy and can be used to measure a wide range of materials. This method also uses only one type of indenter. The method is easier for the operator because you don’t have to keep changing the indenter each time you want to test a new test piece.
VII. Comparison of Vickers and Brinell
Test piece must be thoroughly prepared
No surface finish is required
Vickers test must have an optical instrument to measure the size of the indent
The indent should be measured under bright light illumination for accurate measurement
Test cycle takes between 30 and 60 seconds making this process slow
This process is rather slow with the test cycle taking between 30 to 60 seconds
The test process can be non-destructive
The method cannot be applied to very thin hard materials
Due to the optical instruments need, this method is more expensive than the Brinell test
When testing pieces for macro range with high loads, there is a risk of deformation on the test piece
The test piece must have a ground and polished or good quality surface
Test piece should have a quality surface because the indent is measured optically
This method uses one type of indenter only
This method uses different sizes of the indenter depending on the test piece material and the size of indentation required
This method can be used to inspect any type of material
Brinell method can only be used to inspect non-homogeneous materials such as castings
The Vickers method has higher accuracy than the Brinell method and can be used to measure softer materials, making it suitable for most applications.
The Vickers hardness test uses a diamond indenter, which does not deform easily even under high loads, while the Brinell hardness test uses a steel ball as an indenter. The indenter used in the Brinell hardness test can deform under heavy loads and make measurements taken inaccurate.
Related Article: Hardness Test Comparison: Vickers vs Rockwell
Related Article: Hardness Test Comparison: Rockwell vs Brinell