The advantages of the Vickers hardness test are that extremely accurate readings can be taken, and just one type of indenter is used for all types of metals and surface treatments. Although thoroughly adaptable and very precise for testing the softest and hardest of materials, under varying loads, the Vickers machine is a floor standing unit that is more expensive than the Brinell or Rockwell machines.

Principle of Vickers Test

The Vickers hardness test method consists of indenting the test material with a diamond indenter, in the form of a right pyramid with a square base and an angle of 136 degrees between opposite faces subjected to a load of 1 to 100 kgf. The full load is normally applied for 10 to 15 seconds.

The two diagonals of the indentation left in the surface of the material after removal of the load are measured using a microscope and their average calculated. The area of the sloping surface of the indentation is calculated. The Vickers hardness is the quotient obtained by dividing the kgf load by the square mm area of indentation.

When the mean diagonal of the indentation has been determined the Vickers hardness may be calculatedfrom the formula, but is more convenient to use conversion tables.

When selecting a hardness tester for your application, it is important for you to consider the following:

1, What kind of hardness scale to be used?
2, What is the material to be tested, and is this material suitable to the type of test method you are considering?
3, How large is the part, component or specimen to be tested?
4, Is the test point difficult to reach?
5, What is the quantity of testing that will be done?
6, How accurate does your test result need to be?
7, What is your budget?
8, What is the required return on investment and do you have ways to measure reductions in costs- yields, throughput, operator efficiency?
9, What testing problems have you experienced in your current method?
10, How knowledgeable are the users of the tester?