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- Knoop_hardness_test abstract "The Knoop hardness test /kəˈnuːp/ is a microhardness test – a test for mechanical hardness used particularly for very brittle materials or thin sheets, where only a small indentation may be made for testing purposes. A pyramidal diamond point is pressed into the polished surface of the test material with a known (often 100g) load, for a specified dwell time, and the resulting indentation is measured using a microscope. The geometry of this indenter is an extended pyramid with the length to width ratio being 7:1 and respective face angles are 172 degrees for the long edge and 130 degrees for the short edge. The depth of the indentation can be approximated as 1/30 of the long dimension. The Knoop hardness HK or KHN is then given by the formula:where:L = length of indentation along its long axisCp = correction factor related to the shape of the indenter, ideally 0.070279P = loadHK values are typically in the range from 100 to 1000, when specified in the conventional units of gf·mm−2. The SI unit, pascals, are sometimes used instead: 1 kgf·mm−2 = 9.80665 MPa.The test was developed by Frederick Knoop and colleagues at the National Bureau of Standards (now NIST) of the USA in 1939, and is defined by the ASTM E384 standard.The advantages of the test are that only a very small sample of material is required, and that it is valid for a wide range of test forces. The main disadvantages are the difficulty of using a microscope to measure the indentation (with an accuracy of 0.5 micrometre), and the time needed to prepare the sample and apply the indenter.Variables such as load, temperature, and environment, may effect this procedure, which have been examined in detail.".
- Knoop_hardness_test thumbnail Knoop-and_Mohs-_scale.svg?width=300.
- Knoop_hardness_test wikiPageExternalLink Knoophard.html.
- Knoop_hardness_test wikiPageExternalLink convert_hardness.cfm?cat=Steel&HD=HK.
- Knoop_hardness_test wikiPageID "1887779".
- Knoop_hardness_test wikiPageRevisionID "572585826".
- Knoop_hardness_test hasPhotoCollection Knoop_hardness_test.
- Knoop_hardness_test subject Category:Hardness_tests.
- Knoop_hardness_test type Abstraction100002137.
- Knoop_hardness_test type Cognition100023271.
- Knoop_hardness_test type Experiment105798043.
- Knoop_hardness_test type HardnessTests.
- Knoop_hardness_test type HigherCognitiveProcess105770664.
- Knoop_hardness_test type Inquiry105797597.
- Knoop_hardness_test type ProblemSolving105796750.
- Knoop_hardness_test type Process105701363.
- Knoop_hardness_test type PsychologicalFeature100023100.
- Knoop_hardness_test type Thinking105770926.
- Knoop_hardness_test type Trial105799212.
- Knoop_hardness_test comment "The Knoop hardness test /kəˈnuːp/ is a microhardness test – a test for mechanical hardness used particularly for very brittle materials or thin sheets, where only a small indentation may be made for testing purposes. A pyramidal diamond point is pressed into the polished surface of the test material with a known (often 100g) load, for a specified dwell time, and the resulting indentation is measured using a microscope.".
- Knoop_hardness_test label "Dureté Knoop".
- Knoop_hardness_test label "Dureza Knoop".
- Knoop_hardness_test label "Escala de Knoop".
- Knoop_hardness_test label "Knoop hardness test".
- Knoop_hardness_test label "Scala di Knoop".
- Knoop_hardness_test label "ヌープ硬度".
- Knoop_hardness_test sameAs Escala_de_Knoop.
- Knoop_hardness_test sameAs Dureté_Knoop.
- Knoop_hardness_test sameAs Scala_di_Knoop.
- Knoop_hardness_test sameAs ヌープ硬度.
- Knoop_hardness_test sameAs Dureza_Knoop.
- Knoop_hardness_test sameAs m.063wg9.
- Knoop_hardness_test sameAs Q2451025.
- Knoop_hardness_test sameAs Q2451025.
- Knoop_hardness_test sameAs Knoop_hardness_test.
- Knoop_hardness_test wasDerivedFrom Knoop_hardness_test?oldid=572585826.
- Knoop_hardness_test depiction Knoop-and_Mohs-_scale.svg.
- Knoop_hardness_test isPrimaryTopicOf Knoop_hardness_test.
