KudoZ question not available
Russian translation: Твердость по Кноопу
| 23:32 Dec 5, 2004 |
| English to Russian translations [PRO] Tech/Engineering - Materials (Plastics, Ceramics, etc.) | |||||||
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|  Selected response from: Sergey Strakhov Local time: 06:12 | ||||||
Grading comment
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| Summary of answers provided | ||||
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| 4 +3 | Кнооп |
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| 4 +3 | Твердость по Кноопу |
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| Discussion entries: 8 | |
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Answers
8 mins confidence: 
peer agreement (net): +3
peer agreement (net): +3| knoop Кнооп Explanation: Knoop = Кнооп "Физический мир";"112 элементов";"Самый твердый элемент";"Алмаз";"Аллотроп углерода (С) алмаз имеет твердость, по методу Кноопа, 8400. Число Кноопа одного из самых мягких минералов, гипса, равно 40." (http://drink.dax.ru/gines/gines_10.shtml) Knoop (HK) hardness was developed by at the National Bureau of Standards (now NIST) in 1939. The indenter used is a rhombic-based pyramidal diamond that produces an elongated diamond shaped indent. Knoop tests are mainly done at test forces from 10g to 1000g, so a high powered microscope is necessary to measure the indent size. Because of this, Knoop tests have mainly been known as microhardness tests. The newer standards more accurately use the term microindentation tests. The magnifications required to measure Knoop indents dictate a highly polished test surface. To achieve this surface, the samples are normally mounted and metallurgically polished, therefore Knoop is almost always a destructive test. (http://www.instron.com/wa/applications/test_types/hardness/k... -------------------------------------------------- Note added at 27 mins (2004-12-05 23:59:42 GMT) -------------------------------------------------- There are some sources where they talk about \"четырехгранной пирамиды Кнуппа\" or \"комплектация для Кнуупа\". I believe Кнууп is OK. It doesn\'t matter if he was from Germany or anywhere else, he worked in the USA. So КНУУП. Knoop hardness Frederick Knoop developed his elongated pyramidal indenter as an alternative to the square-base pyramidal Vickers indenter, in large part to overcome the cracking observed in brittle materials. Indeed, experience with a wide range of ceramics has proven that the Knoop indentations are far less likely to crack. Besides ASTM standard E 384, Microhardness of Materials, three material-specific Knoop hardness standards have been developed: C 730 for Glass and Glass Ceramics, which recommends a load of 0.98 N (100 gf) C 849 for Whitewares, with 9.8 N (1 kgf) C 1326 for Advanced Ceramics, with 9.8 N (1 kgf) The European Community prestandard, CEN ENV 843-3, has both Knoop and Vickers hardness methods as well as Rockwell A and N scales. In addition, a new ISO Ceramic Hardness standard is in preparation in Technical Committee TC 206, Fine Ceramics, and will include both Knoop and Vickers hardness. Knoop indentations are about 2.8 times longer and are shallower than Vickers indentations made at the same load. In principle, the longer indentations should make an easier-to-read indentation, but in practice the length advantage is offset by the greater difficulty in determining where the tapered tip ends. Knoop hardness number A number obtained by dividing the load in kg applied to a pyramid-shaped diamond of specific size divided by the projected area of the impression: KHN = L/A, where A= the projected area of the impression in mm2 and L= the load in kg; used for measurements of hardness of any materials, especially very hard and brittle substances such as tooth dentin and enamel. |
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