In hardness testing, what does HV represent?

• A. Brinell hardness value.
• B. Vickers hardness number.
• C. Rockwell hardness value.
• D. Shore hardness value.

Answer: (B)

Hardness tests use different scales to quantify how resistant a material is to indentation. HV is the Vickers hardness value. In this test, a diamond pyramid is pressed into the material under a precise load, leaving a square impression. You measure the two diagonals of that square and use their average to determine the contact area of the indentation. Hardness is calculated as the applied force divided by that area, with the standard formula HV = 1.854 F / d^2, where F is the load (in kilogram-force) and d is the average diagonal (in millimeters). This gives a single numerical value that can be compared across materials. Other hardness tests use different indenters and formulas—for example, Brinell uses a ball, Rockwell uses depth with different scales, and Shore is used for polymers—so their numbers aren’t directly interchangeable with Vickers.