How Vickers Hardness Test Works ?

The Vickers method is based on an optical measurement system. 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 diagonal of the resulting indention is measured under a microscope and the Vickers Hardness value read from a conversion table 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.

Vickers Pyramid Hardness Indentation

F= Load in kgf
d = Arithmetic mean of the two diagonals, d1 and d2in mm

HV = Vickers hardness

Vickers Pyramid Hardness Formula

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. The Vickers method is capable of testing the softest and hardest of materials, under varying loads and we can easily testing very thin materials like foils or measuring the surface of a part, small parts or small areas, measuring individual micro structures, or measuring the depth of case hardening by sectioning a part and making a series of indentations to describe a profile of the change in hardness.

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