ISO-14420-2005.pdf

Reference number ISO 14420:2005(E) © ISO 2005 INTERNATIONAL STANDARD ISO 14420 First edition 2005-07-01 Carbonaceous products for the production of aluminium Baked anodes and shaped carbon products Determination of the coefficient of linear thermal expansion Produits carbonés utilisés pour la production de l'aluminium Anodes cuites et produits carbonés formés Détermination du coefficient de dilatation thermique ISO 14420:2005(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. 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ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii © ISO 2005 All rights reserved ISO 14420:2005(E) © ISO 2005 All rights reserved iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 14420 was prepared by Technical Committee ISO/TC 226, Materials for the production of primary aluminium. -,-,- ISO 14420:2005(E) iv © ISO 2005 All rights reserved Introduction This International Standard is based on DIN 51909:1984 prepared by the committee NMP 281 “Prüfverfahren für Kohlenstoff und Graphit” in DIN Deutsches Institut für Normung e.V., Berlin. -,-,- INTERNATIONAL STANDARD ISO 14420:2005(E) © ISO 2005 All rights reserved 1 Carbonaceous products for the production of aluminium Baked anodes and shaped carbon products Determination of the coefficient of linear thermal expansion 1 Scope This International Standard specifies a method to determine the coefficient of linear thermal expansion of carbonaceous or graphite materials (solid materials) for the production of aluminium between 20 °C and 300 °C. It applies to baked anodes and shaped carbon products. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 6906, Vernier callipers reading to 0,02 mm ISO 3611, Micrometer callipers for external measurement DIN 1333, Presentation of numerical data 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 linear thermal expansion coefficient thermal expansion coefficient () correlated with the length change of a body with temperature NOTE The linear thermal expansion coefficient is calculated from the following formula. ( ) 1d d l a l = (1) where ( ) is the linear expansion coefficient; l is the length of the test specimen at temperature ; d d l is the length change with temperature. ISO 14420:2005(E) 2 © ISO 2005 All rights reserved 3.2 average linear thermal expansion coefficient average linear expansion coefficient (1,2) correlated with the length change of a body with temperature NOTE The average linear expansion coefficient is calculated from the following formula () 21 12 1211 11 ; lll ll = (2) 21 = (3) 21 lll = (4) where 1 is the lower limit of the temperature interval, in °C; 2 is the upper limit of the temperature interval, in °C; l1 is the length of the test specimen, in mm, at temperature 1; l2 is the length of the test specimen at temperature 2; is the mean linear thermal expansion coefficient, in units of 1/K, of the sample holder and the push-rod for the temperature range under consideration. 4 Principle The average linear thermal expansion coefficient is determined by means of a push-rod dilatometer. The test specimen is contained in a sample holder made from low-expansivity material (such as flint glass). It is heated in a furnace and the length change is transmitted to a mechanical, optical, or electronic measuring system outside the furnace by a push-rod. The average linear thermal expansion coefficient is calculated from the measured length change, the original length, and the temperature change of the test specimen, taking the expansion of the sample holder and the push-rod into account. Unless otherwise stated, the determination is performed between a lower limit for the temperature interval of 20 °C (i.e. room temperature) and an upper limit for the temperature interval of 300 °C max. 5 Apparatus 5.1 Dilatometer, with sample holder and push-rod, for example, made from flint glass, as well as a mechanical, optical or electronic length-measurement device (error limits ± 0,5 µm), for temperatures above 300 °C in a vacuum or in a protective gas atmosphere; 5.2 Furnace, capable of holding the temperature constant to within ± 0,5 % over the length of the test specimen; 5.3 Temperature-measuring device, for example, a thermocouple with indicating instrument, accurate to within ± 0,5 %, to determine the average test-specimen temperature; 5.4 Instrument for measuring lengths, with error limit of ± 0,2 %, for example vernier calliper according to ISO 6906 or micrometer calliper according to ISO 3611; 5.5 Calibration samples, made from materials with known thermal expansivity in the range of the material to be measured and made with similar geometry. The thermal expansivity of calibration samples shall have been predetermined by the producer of the measuring equipment or by a recognised calibration authority. -,-,- ISO 14420:2005(E) © ISO 2005 All rights reserved 3 6 Specimens Prepare a test specimen of cylindrical or prismatic geometry. The cylinder diameter or the prism transverse edge length shall be at least twice the diameter of the largest structural constituent (for example maximum grain size) of the material to be examined, and in no case smaller than 4 mm (typically 30 to 50 mm). The length of the test specimens shall be at least 25 mm, but preferably should be 50 mm to 120 mm. The test specimens shall be machined on all surfaces by turning or grinding, so that the surfaces in contact with the push-rod do not deviate from plane parallelism by more than 0,2 mm. A hole of minimum 1 mm depth may be drilled in the middle of a long side of the test specimen to hold the joint of the thermocouple. Remove existing stresses in a test specimen by annealing at 1 000 °C in a non-oxidizing atmosphere. 7 Procedure 7.1 Calibration Calibrate the dilatometer according to 7.2 using calibrated samples. 7.2 Measurement Measure the sample length l1 of the test specimen at temperature 1. Insert the test specimen into the dilatometer, taking care that the specimen ends are firmly in contact with the push-rod. Insert the joint of the thermocouple into the hole in the side of the test specimen where required. Measure the original length l1 of the test specimen at the lower limit of the temperature interval 1. If the push-rod planes contacting the specimen end surfaces are not spherically or conically shaped, use connecting pieces to realize a point contact to the specimen end planes. At the beginning of the measurement, set the measuring system to zero by either adjusting the zero point of the apparatus, or marking on the recording chart or the photosensitive paper. When using double dilatometers, with the two dilatometer motions recorded orthogonally, the assignment of the recording axes to the dilatometers shall also be determined and recorded. Position the furnace (which may be preheated) around the sample holder. Allow the test specimen to attain the upper limit of the temperature interval 2. Then measure and record the length of the test specimen l2. If the upper limit of the temperature interval 2 is above 300 °C, avoid oxidation of the test specimen by applying a suitable protection gas or vacuum. 8 Evaluation Calculate the average linear expansion coefficient, in units of 1/K, according to the following equation: 1 (;) 21 12kk 121 11 lll ll = (5) where 1 is the lower limit of the temperature interval, in °C; 2 is the upper limit of the temperature interval, in °C; l1 is the length of the test specimen, in mm, at temperature 1; ISO 14420:2005(E) 4 © ISO 2005 All rights reserved l2 is the length of the test specimen, in mm, at temperature 2. k is the mean linear thermal expansion coefficient, in units of 1/K, of the sample holder and the push-rod for the temperature range under consideration. Rounding to the last significant decimal place shall be done in accordance with DIN 1333. 9 Test report The test report shall include the following information: a) type and marking of specimens; b) a reference to this International Standard; c) pretreatment of the specimens, if relevant; d) number of specimens; e) temperature range of measurement; f) average linear thermal expansion coefficient, in units of 106 × K1, rounded to the nearest 0,1 × 106 × K1, individual values, mean value; g) agreed conditions deviating from this International Standard; h) test date. 10 Precision The precision of this method has been calculated according to ASTM E691, resulting in the following values: The repeatability: r = 0,1 µm/mK The reproducibility: R = 0,17 µm/mK -,-,- ISO 14420:2005(E) © ISO 2005 All rights reserved 5 Bibliography 1 DIN 863-1, Verification of geometrical parameters Micrometers Part 1: Standard design micrometer callipers for external measurement; concepts, requirements, testing 2 DIN 1319-3, Fundamentals of metrology Part 3: Evaluation of measurements of a single measurand, measurement uncertainty 3 DIN 51045-1, Determination of the thermal expansion of solids Part 1: Basic rules 4 DIN 51045-2, Determination of the change of length of solids by thermal effect; testing of fired fine ceramic materials 5 DIN 51045-3, Determination of the change of length of solids by thermal effect; testing of non-fired fine ceramic materials 6 DIN 51045-4, Determination of the change of length of solids by thermal effect; testing of fired ordinary ceramic materials 7 DIN 51045-5, Determination of the change of length of solids by thermal effect; testing of non-fired ordinary ceramic materials 8 DIN 51909:1998, Testing of carbon materials Determination of coefficient of linear thermal expansion Solid materials 9 ASTM C372, Standard method of test for linear thermal expansion of fired whiteware products by the dilatometer method (reapproved 1970) 10 ASTM E691, Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method 11 KOHLRAUSCH, F., Praktische Physik, Stuttgart 1968, Vol. 1, pp. 316 to 319, Chapter 4.3.2 “Wärmeausdehnung” 12 METZ, A., A new all-purpose dilatometer according to Bollenrath (in German), ATM 303 (1961) R 61 to R 72 13 THORMANN, P., Investigations with a dilatometer in the field of ceramic raw materials and materials (in German), Ber. dt. Keram. Ges. 46 (1969), pp. 583 to 586 14 THORMANN, P., Precision of dilatometric investigations and their significance in ceramic laboratories (in German), Ber. dt. Keram. Ges. 47 (1970), pp. 769 to 773 15 OTTO, J. and THOMAS, W., The thermal Expansion of Quartz Glass in the Temperature Range O to 1060°C (in German), Z. f. Phys. 175 (1963), pp. 334 to 337 -,-,- ISO 14420:2005(E) ICS 71.100.10 Price based on 5 pages © ISO 2005 All rights reserved -,-,-