Vickers hardness testing principle
Description
The Vickers hardness test uses a square-based pyramid diamond indenter with an angle of 136° between the opposite faces at the vertex, which is pressed into the surface of the test piece using a prescribed force, F. The time for the initial application of the force is 2 s to 8 s, and the test force is maintained for 10 s to 15 s. After the force has been removed, the diagonal lengths of the indentation are measured and the arithmetic mean, d, is calculated. The Vickers hardness number, HV, is given by:
HV = Constant × Test force / Surface area of indentation
Standard Vickers Scales
|
Micro-hardness |
Test force |
Low-force |
Test force |
Macro-hardness |
Test force |
|
HV 0.01 |
0.09807 |
HV 0.2 |
1.961 |
HV 5 |
49.03 |
|
HV 0.015 |
0.1471 |
HV 0.3 |
2.942 |
HV 10 |
98.07 |
|
HV 0.02 |
0.1961 |
HV 0.5 |
4.903 |
HV 20 |
196.1 |
|
HV 0.025 |
0.2452 |
HV 1 |
9.807 |
HV 30 |
294.2 |
|
HV 0.05 |
0.4903 |
HV 2 |
19.61 |
HV 50 |
490.3 |
|
HV 0.1 |
0.9807 |
HV 3 |
29.42 |
HV 100 |
980.7 |
Standards
|
BS EN ISO 6507-1:2018 (BS 427:Part 1:1961) |
Metallic materials. Vickers hardness test. Test method |
|
ASTM E92-17 |
Standard Test Method for Vickers Hardness of Metallic Materials |