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# Topic: Knoop hardness test

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 NationMaster - Encyclopedia: Hardness Hardness is a measure of dissolved mineral salts, mainly calcium and magnesium carbonates, in water. Hardness has a direct affect on the cellular functions of fish, plants and microorganisms and although fish from hard water areas do not seem to suffer from softer than natural conditions the reverse does not apply. Hardness is expressed in degrees but the units differ form country to country and test kit measurements vary depending on whether total hardness or carbonate hardness is being determined. www.nationmaster.com /encyclopedia/Hardness   (392 words)

 Vickers hardness test The Vickers hardness test was developed in the early 1920s as an alternative method to measure the hardness of materials. The hardness number can be converted into units of Pa, but should not be confused with a pressure, which also has units of Pa. The hardness number is determined by the load over the surface area of the indentation and not the area normal to the force, and is therefore not a pressure. The Vickers hardness test uses a diamond, with the shape of square-based pyramid with an angle of 136Â° between opposite faces as an indenter (22Â° between the indenter face and surface). www.algebra.com /algebra/about/history/Vickers-hardness-test.wikipedia   (493 words)

 eFunda: Convert Hardness: Knoop The Knoop Hardness Test, using an elongated pyramidal indenter, is a micro-indentation method suitable for thin plastic sheets, thin metal sheets, brittle materials, or materials where the applied load must never exceed 3.6 kgf. In the Knoop Hardness Test, a load (typically in the range of 25 ~ 3600 gf) is applied to the surface of the test specimen via a pyramidal diamond indenting tool. The Knoop hardness number is the ratio of the applied load to the area of the indentation, in accordance with the formula: www.efunda.com /units/hardness/convert_hardness.cfm?HD=HK&Cat=Steel   (330 words)

 Take a BrainSip The Knoop hardness test 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 force, for a specified dwell time, and the resulting indentation is measured using a microscope. The test was developed by F. Knoop and colleagues at the National Bureau of Standards (now NIST) of the USA in 1939, and is defined by the ASTM D-1474 standard. knoop-hardness-test.brainsip.com   (229 words)

 Hardness The hardness is calculated by dividing the load by the area of the curved surface of the indention, (the area of a hemispherical surface is arrived at by multiplying the square of the diameter by 3.14159 and then dividing by 2). A diamond-tipped hammer in a graduated glass tube is allowed to fall from a known height on the specimen to be tested, and the hardness number depends on the height to which the hammer rebounds; the harder the material, the higher the rebound [14]. The Mohs hardness [19] of a mineral is determined by observing whether its surface is scratched by a substance of known or defined hardness. www.calce.umd.edu /general/Facilities/Hardness_ad_.htm   (5414 words)

 Hardness Definitions The Mohs hardness of a mineral is determined by observing whether its surface is scratched by a substance of known or defined hardness. For this reason the Mohs test, while greatly facilitating the identification of minerals in the field, is not suitable for accurately gauging the hardness of industrial materials such as steel or ceramics. The diamond indenter employed in the Knoop test is in the shape of an elongated four-sided pyramid, with the angle between two of the opposite faces being approximately 170° and the angle between the other two being 130°. www.waldaninternational.com /hardnessDef.shtml   (890 words)

 Knoop Hardness Test Knoop tests are mainly done at test forces from 10g to 1000g, so a high powered microscope is necessary to measure the indent size. Knoop testing is done with a rhombic-based pyramidal diamond indenter that forms an elongated diamond shaped indent. The Knoop hardness number is a function of the test force divided by the projected area of the indent. www.instron.com /wa/applications/test_types/hardness/knoop.aspx   (468 words)

 Hardness Testing 260 - Inspection Training A hardness test that measures the diameter of a circle formed by the penetration of a 10 mm steel ball under a fixed load pressure. Hardness is generally measured by the depth or area of penetration under a fixed load using a diamond indenter. A hardness test that measures the degree of penetration into a metal caused by a diamond or ball indenter that is applied under a fixed load. www.toolingu.com /class_class_desc.aspx?class_ID=350260   (1070 words)

 [No title]   (Site not responding. Last check: ) Определение твердости по склероскопу (по Шору) - Scleroscope hardness test Определение твердости поверхности по Роквеллу - Rockwell superficial hardness test Определения твердости по Кнупу - Knoop hardness test www.metalportal.com.ua /words.php?whatis=&letter=all&page=156   (102 words)

 Vickers hardness test - Encyclopedia, History, Geography and Biography The Vickers hardness test was developed in the early 1920s as an alternative method to measure the hardness of materials. The hardness number can be converted into units of Pa, but should not be confused with a pressure, which also has units of Pa. The hardness number is determined by the load over the projected area of the indentation and not the area normal to the force, and is therefore not a pressure. The Vickers hardness test uses a diamond, with the shape of square-based pyramid with an angle of 136° between opposite faces as an indenter. www.arikah.com /encyclopedia/Vickers_hardness_test   (576 words)

 Mohs hardness scale@Everything2.com The Mohs hardness scale is a measure of a mineral's resistance to scratching or being sawed apart, not of the tenacity, which is whether the mineral can be shattered or split in two by impact. The Mohs hardness scale was devised by Friedrich Mohs in 1812. The hardness of a material is determined by its surface properties, and those are often not as well-defined as its bulk properties, because of external influences. www.everything2.com /index.pl?node=Mohs%20hardness%20scale   (622 words)

 United States Products Co. - Lapping/Polishing Compounds Most hardness tests for metals yield a numerical value and are based on their resistance to permanent indentation under the conditions imposed by the particular test. Hardness tests are made under arbitrary conditions and there are no basic correlations for converting numbers from one scale to another. In the Brinnell hardness test, a known load is applied, for a given length of time, to the surface of a specimen through a hardened steel ball of known diameter. www.us-products.com /sitehtml/lappinggrind.html   (702 words)

 Application by Test Type - Hardness Hardness is, however, used extensively to characterize materials and to determine if they are suitable for their intended use. All of the hardness tests described in this section involve the use of a specifically shaped indenter, significantly harder than the test sample, that is pressed into the surface of the sample using a specific force. The most common uses for hardness tests is to verify the heat treatment of a part and to determine if a material has the properties necessary for its intended use. www.instron.se /wa/applications/test_types/hardness   (375 words)

 Hardness Testing, Portable Micro-Hardness, Brinell, Vickers, Rockwell, India The test consists of applying a prescribed load, usually between 500kg and 3000kg for a specified time (10-30 seconds) using a 5 or 10mm diameter tungsten carbide ball on the flat surface of a metal sample. This test differs from the Brinell test in the shape of the indenter and in the manner that the number is determined. The hardness number is based upon the measurements made of the indent formed in the surface of the test specimen. www.tcreng.com /services/hardness-brinell-knoop-vickers-rockwell-micro-portable.shtml   (328 words)

 Hardness In materials science, hardness is the characteristic of a solid material expressing its resistence to penetration, and by extension its power of penetration in softer materials. An object made of a hard material will scratch an object made of a softer material. Hardness is usually measured on various scales, such as the Rockwell scale or the Mohs scale. www.ebroadcast.com.au /lookup/encyclopedia/ha/Hardness.html   (87 words)

 :: K :: Glossary of Cutting and Grinding Terms - Cutting Tool Engineering Magazine   (Site not responding. Last check: ) Knoop hardness number, HK Number related to the applied load and to the projected area of the permanent impression made by a rhombic-based pyramidal diamond indenter having included edge angles of 172º 30' and 130º 0'. The Knoop hardness number is the ratio of the applied load (usually, 0.5 kgf and greater) to the projected area of indentation measured in mm2. Test for determining the hardness of a material in which calibrated machines force a rhombic-base pyramidal diamond indenter having specified edge angles into the surface of the material. www.ctemag.com /glossary/k.php   (375 words)

 Hardness Test Blocks & Accessories - Extec ® Corp. EXTEC Micro Hardness Test Blocks- Vickers (HV), Knoop (HK) and Dual (HV/HK) meet ASTM E384 standards and conform to A2LA and NVLAP specifications. EXTEC Rockwell Test Blocks meet the ASTM E18 standard and conform to A2LA and NVLAP specifications. Rockwell HRC Test Blocks are traceable to NIST. www.extec.com /hardnesstestblocks.htm   (170 words)

 Microhardness Testing The procedure for testing is very similar to that of the standard Vickers hardness test, except that it is done on a microscopic scale with higher precision instruments. The Knoop hardness number KHN is the ratio of the load applied to the indenter, P (kgf) to the unrecovered projected area A (mm The Knoop indenter is a diamond ground to pyramidal form that produces a diamond shaped indentation having approximate ratio between long and short diagonals of 7:1. www.gordonengland.co.uk /xhardness/xmicrohardness.htm   (618 words)

 Hardness Hardness can be measured on the Mohs scale or various other scales. Scratch hardness is usually measured on the Mohs scale of mineral hardness. One scale that measures rebound hardness is the Bennett Hardness Scale. www.dejavu.org /cgi-bin/get.cgi?ver=93&url=http%3A%2F%2Farticles.gourt.com%2F%3Farticle%3Dhardness%26type%3Den   (474 words)

 Hardness Testers and Hardness Testing Machines From Zwick For A Range of Materials and Environments   (Site not responding. Last check: ) For the testing of the indentation hardness on plastics, Rockwell hardness on metals, plastics and carbon materials as well as the hardness of building plaster and asphalt. The hardness testing device for optical measurements is integrated in a zwicki testing machine. The Master test program developed for the hardness measurement head allows to carry out hardness tests according to Martens, Rockwell and ball indentation hardness as well as Vickers and Brinell hardness according to the method HVT and HBT (indentation depth measurement). www.azom.com /Details.asp?ArticleID=3763   (1147 words)

 Cooking For Engineers - Equipment & Gear: Knife and Sharpening Steel Hardness As HRC testing does leave a noticeable indent in the surface of the tested part, the Rockwell 15N (HR15N) scale was chosen to perform the test with the results converted to HRC. Hardness testing of different metals can be compared as long as those metals are relatively close in physical and mechanical properties. The hardness of the sharpening steels relative to the knives indicates that there probably is some sharpening going on of the less hard knives regardless of which steel that I use. www.cookingforengineers.com /article/187/Knife-and-Sharpening-Steel-Hardness   (1093 words)

 Knoop Hardness Testing Knoop (HK) hardness was developed by at the National Bureau of Standards (now NIST) in 1939. Knoop tests are mainly done at test forces from 10g to 1000g, so a high powered microscope is necessary to measure the indent size. Knoop test methods are defined in ASTM E384. www.wilsoninstruments.com /applications/knoop.aspx   (447 words)

 Testing & Certification - Hardness Testing Leeb testing measures hardness by using a calibrated instrument that impacts a diamond tipped body (generated by a spring force) onto the surface of the material to be tested. The ratio of the rebound velocity to the impact velocity is a measure of the hardness. Rockwell hardness testing to the B, C, 15Tand 15N scales is conducted on three Wilson Rockwell hardness testers. www.tcindustries.com /testing/hardness.html   (305 words)

 Colorado State University - Pueblo < MET 203 - Sheet Metal Bending   (Site not responding. Last check: ) The procedure for testing is very similar to that of the standard Vickers hardness test, except that it is done on a microscopic scale with higher precision instruments. The Knoop hardness number KHN is the ratio of the load applied to the indenter, F (kg) to the unrecovered projected area A (mm The Knoop indenter is a diamond ground to pyramidal form that produces a diamond shaped indentation having approximate ratio between long and short diagonals of 7:1. ceeps.colostate-pueblo.edu /MET/MET203/Fall2005/hardness/Micro.htm   (368 words)

 ÖdevSitesi.Com - 101389-hardness test [12 Sayfa] Preferences 2.OBJECTIVE The objective of this lab is to introduce the students to the topic of the indentation hardness of metals using the common hardness tests and scales (e.g. The way the three of these hardness tests measure a metals hardness is to determine the metals resistance to the penetration of a non-deformable ball or cone. Brinell hardness testing involves forcing a hardened steel ball (or a tungsten carbide ball for extremely hard materials) into the surface of the specimen. www.odevsitesi.com /odevler/2005_6/101389-hardness-test.htm   (522 words)

 Knoop Hardness Test Knoop tests are mainly done at test forces from 10g to 1000g, so a high powered microscope is necessary to measure the indent size. Knoop test methods are defined in ASTM E384. Where 450 is the calculated hardness and 0.5 is the test force in kg. www.instron.it /wa/applications/test_types/hardness/knoop.aspx   (466 words)

 Vickers Hardness Test The Vickers hardness test was developed in the early 1920s and uses a pyramid-shaped indenter made of diamond. The Vickers Hardness (HV) is then determined from the formula HV = (1.854 F / D^2) where F= applied load, kg; and D= the diagonal of the impression made by the indenter, mm, as indicated in the figure. When quoting a Brinell hardness number (HB), the conditions of the test used to obtain the number must be specified. www.aardogs.com /pages10/94/vickers-hardness-test.html   (882 words)

 IngentaConnect Thermal Conductivity and Elastic Modulus Evolution of Thermal Bar... Hardness and elastic modulus gradients across a 1.5 mm thick TBC system were also determined as a function of laser testing time using the laser sintering/creep and microindentation techniques. The coating Knoop hardness values increased from the initial hardness value of 4 GPa to 5 GPa near the ceramic/bond coat interface and to 7.5 GPa at the ceramic coating surface after 120 h of testing. The increase in thermal conductivity and the evolution of significant hardness and modulus gradients in the TBC systems are attributed to sintering-induced microporosity gradients under the laser-imposed high thermal gradient conditions. www.ingentaconnect.com /content/asm/jtst/2000/00000009/00000002/art00002   (334 words)

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