Knoop hardness Calculator

✖Indentation load in microhardness test. Loads will be in the range of 1-1000 grams.ⓘ Indentation Load [P]			+10% -10%
✖Diagonal length in microhardness test. The diagonal length is in millimetre.ⓘ Diagonal length [d]			+10% -10%

✖Knoop hardness test comprises of 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 [HK]

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Formula

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Knoop hardness

Formula

`"HK" = 14.2*"P"/("d"^2)`

Example

`"0.491349kgf/mm²"=14.2*"0.1kgf"/(("1.7mm")^2)`

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Knoop hardness Solution

STEP 0: Pre-Calculation Summary

Formula Used

Knoop hardness = 14.2*Indentation Load/(Diagonal length^2)
HK = 14.2*P/(d^2)
This formula uses 3 Variables

Variables Used

Knoop hardness - (Measured in Pascal) - Knoop hardness test comprises of 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).
Indentation Load - (Measured in Newton) - Indentation load in microhardness test. Loads will be in the range of 1-1000 grams.
Diagonal length - (Measured in Meter) - Diagonal length in microhardness test. The diagonal length is in millimetre.

STEP 1: Convert Input(s) to Base Unit

Indentation Load: 0.1 Kilogram-Force --> 0.980664999999931 Newton (Check conversion here)
Diagonal length: 1.7 Millimeter --> 0.0017 Meter (Check conversion here)

STEP 2: Evaluate Formula

Substituting Input Values in Formula

HK = 14.2*P/(d^2) --> 14.2*0.980664999999931/(0.0017^2)

Evaluating ... ...

HK = 4818492.38754291

STEP 3: Convert Result to Output's Unit

4818492.38754291 Pascal -->0.491349480968858 Kilogram-Force per Square Millimeter (Check conversion here)

FINAL ANSWER

0.491349480968858 ≈ 0.491349 Kilogram-Force per Square Millimeter <-- Knoop hardness

(Calculation completed in 00.020 seconds)

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Created by Hariharan V S

Indian Institute of Technology (IIT), Chennai

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< 4 Hardness Calculators

Brinell hardness

Go Brinell Hardness = 2*Indentation Load/(pi*Diameter of the indenter*(Diameter of the indenter-sqrt(Diameter of the indenter^2-Diameter of the indentation^2)))

Vickers hardness

Go Vickers Hardness = 1.854*Indentation Load/(Diagonal length^2)

Knoop hardness

Go Knoop hardness = 14.2*Indentation Load/(Diagonal length^2)

Tensile strength from Brinell hardness

Go Tensile Strength = (3.45/9.8067)*Brinell Hardness

Knoop hardness Formula

Knoop hardness = 14.2*Indentation Load/(Diagonal length^2)
HK = 14.2*P/(d^2)

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 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) & Diagonal length (d) and hit the calculate button. Here is how the Knoop hardness calculation can be explained with given input values -> 5E-8 = 14.2*0.980664999999931/(0.0017^2).

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 & 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) & Diagonal length (d). With our tool, you need to enter the respective value for Indentation Load & 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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