Hariharan V S
Indian Institute of Technology (IIT), Chennai
Hariharan V S has created this Calculator and 25+ more calculators!

## < 1 Other formulas that you can solve using the same Inputs

Vickers hardness

### Knoop hardness Formula

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## Knoop Hardness test

The Knoop hardness (HK) results from the quotient of the test force and the projection surface (surface area) of the indent, calculated using the longer diagonal of the rhombic pyramidal indentation. Knoop method is particularly suitable for thin and narrow specimens and for testing brittle materials.

## How to Calculate Knoop hardness?

Knoop hardness calculator uses Knoop hardness=14.2*Indentation Load/(Diagonal length^2) to calculate the Knoop hardness, Knoop hardness test involves pressing the pyramid-shaped rhombic indenter (longitudinal edge angle 172.5°, transverse edge angle 130°) into a specimen with a defined test load (between 1 gf and 2 kgf). Knoop hardness and is denoted by HK symbol.

How to calculate Knoop hardness using this online calculator? To use this online calculator for Knoop hardness, enter Indentation Load (P) and Diagonal length (d) and hit the calculate button. Here is how the Knoop hardness calculation can be explained with given input values -> 1.42 = 14.2*0.980664999999931/(0.001^2).

### FAQ

What is Knoop hardness?
Knoop hardness test involves pressing the pyramid-shaped rhombic indenter (longitudinal edge angle 172.5°, transverse edge angle 130°) into a specimen with a defined test load (between 1 gf and 2 kgf) and is represented as HK=14.2*P/(d^2) or Knoop hardness=14.2*Indentation Load/(Diagonal length^2). Indentation load in microhardness test. Loads will be in the range of 1-1000 grams and Diagonal length in microhardness test. The diagonal length is in millimetre.
How to calculate Knoop hardness?
Knoop hardness test involves pressing the pyramid-shaped rhombic indenter (longitudinal edge angle 172.5°, transverse edge angle 130°) into a specimen with a defined test load (between 1 gf and 2 kgf) is calculated using Knoop hardness=14.2*Indentation Load/(Diagonal length^2). To calculate Knoop hardness, you need Indentation Load (P) and Diagonal length (d). With our tool, you need to enter the respective value for Indentation Load and Diagonal length and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well.
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