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1、 i AS 1774.262008 ISO 3187:1989 Australian Standard Refractories and refractory materialsPhysical test methods Method 26: Creep in compressionDeformation under constant load and constant temperature PREFACE This Standard was prepared by the Standards Australia Committee MN-007, Refractories and Refr
2、actory Materials, to supersede AS 1774.261995, Refractories and refractory materialsPhysical test methods, Method 26: Creep in compressionDeformation under constant load and constant temperature. The objective of this Standard is to provide the refractories industry with an internationally accepted
3、method for determining the deformation of a shaped refractory specimen when subjected to a constant compressive stress at a constant temperature. This Standard is identical to and has been reproduced from ISO 3187:1989, Refractory productsDetermination of creep in compression As this Standard is rep
4、roduced from an international standard, the following applies: (a) Its number appears on the cover and title page while the international standard number appears only on the cover. (b) In the source text this International Standard should read this Australian Standard. (c) Replace Item (c) in Clause
5、 9 with reference to this Australian Standard, AS 1774.26; (d) A full point substitutes for a comma when referring to a decimal marker. References to International Standards should be replaced by references to Australian Standards, as follows: Reference to International Standard Australian Standard
6、ISO AS R836 Vocabulary for the refractories industry 2780 Refractories and refractory materialsGlossary of terms 1174 Refractoriesand refractory materialsPhysical test methods 1893 Refractory products Determination of refractoriness- under load (differential-with rising temperature) 1774.12 Method 1
7、2: Refractoriness under loadTemperatures of deformation at constant load with rising temperature International references that are not listed have not been adopted as Australian Standards. AS 1174.262008 i i ii NOTES ii ii The Standard is downloaded from Standard Sharing 1 1 www.standards.org.au St
8、andards Australiawww.standards.org.au Standards Australia ISO 3187 : 1989 (EI 5.1.2 Fixed column, at least 45 mm in Overall diameter and with an axial bore (see 5.1.5). 5.1.3 Moving column, at least 45 mm in Overall diameter. NOTE - Arrangements tan be made for the upper moving column to be fixed to
9、 the furnace, and the combination of furnace and column then forms the moveable loading device. 5.1.4 Two discs, 5 mm to 10 mm thick and at least 50 mm in diameter of an appropriate refractory material compatible with the material under test (e.g. high-fired mullite or alumina for alumino-silicate p
10、roducts, and magnesia or spinel for basic products) which are placed between the test piece and the fixed and moving columns. The disc placed between the test piece and the fixed column shall have a central bore (see 5.1.5). The ends of the fixed and moving columns shall be plane and perpendicular t
11、o their axes; the faces of each disc shall be plane and parallel. NOTE - Platinum or platinum/rhodium sheet (0,2 mm) may be placed between the Sample and the discs to prevent Chemical reaction, par- ticularly in the case of silica. 5.1.5 The arrangement of the two columns, the two discs, the platinu
12、m sheet if used, and the test piece is shown in figure 2, which also Shows typical diameters of the bores in the fixed column and in the disc between them. 5.1.6 The columns and discs shall be capable of withstanding the applied load up to the final test temperature without signifi- cant deformation
13、. There should be no reaction between the discs and the loading System. 5.2 Furnace (preferably with a vertical axis), capable of rais- ing the temperature of the test piece to the final test temperature at the specified rate (see 7.4) in an atmosphere of air. The temperature of the region of the fu
14、rnace occupied by the test piece, when above 500 OC at a stable temperature, shall be uniform around the test piece (12,5 mm above and below) to within + 20 K; this shall be verified by carrying out tests using thermocouples located at different Points on the curved surface of the test piece. During
15、 the period of constant temperature, the fluctuations of temperature indicated by the control thermocouple shall not exceed 5 K. NOTE - The furnace design should be such that the whole of the column assembly tan be easily reached, either by movement of the supporting column or, if access into the fu
16、rnace is restricted, by move- ment of the furnace itself. The assembly should be such that the test piece and loading column stand vertically and Co-axial with the support column when unrestrained. 53 . Measuring device, consisting of the following items : 5.3.1 Outer alumina tube, placed inside the
17、 fixed column to abut on the lower side of the lower disc, and free to move within the fixed column (see 5.3.3). 5.3.2 Inner alumina tube, placed inside the outer tube and passing through the bores in the lower disc and in the test piece to abut on the lower face of the upper disc, and free to move
18、within the outer tube, the lower disc and the test piece (sec 5.3.3). 5.3.3 The arrangement of the two tubes, the two discs and the test piece as shown in figure 2, which also indicates typical external and internal diameters of the outer and inner tubes. 5.3.4 Appropriate measuring instrument (for
19、example a dial-gauge or a length transducer connected to an automatic recording System), fixed to the end of the outer tube (see 5.3.1) and actuated by the inner tube (see 5.3.2). The sensitivity of the measuring device shall be at least 0,005 mm. 5.3.5 The alumina tubes shall be capable of withstan
20、ding the load imposed on them by the measuring instrument at all temperatures up to the final test temperature without signifi- cant distortion. 5.4 Temperature-measurement devices 5.4.1 Central thermocouple, passing through the inner alumina tube (see 5.3.2) of the dilatometer, with its junction at
21、 the mid-Point of the test piece, for measuring the temperature of the test piece at its geometric centre. 5.4.2 Control thermocouple, which shall be placed in a sheath and situated outside the test piece (see figure l), for regulating the rate of rise of temperature. NOTE - For certain furnace plac
22、e the thermocouple nearer constructions, to the heating it may be advisable to elements. 5.4.3 The thermocouples shall be made from platinum and/or platinum-rhodium wire, and shall be compatible with the final test temperature. They shall be in accordance with IEC 584-1 or 584-2. 5.4.4 The accuracy
23、of the thermocouples shall be checked on a regular basis. 5.5 Calipers, to measure to 0,l mm. 6 Test piece 6.1 The test piece shall be a cylinder 50 mm + 0,5 mm in diameter and 50 mm + 0,5 mm in height, with a hole from 12 mm to 13 mm in diameter, extending throughout the height of the test piece, b
24、ored co-axially with the outer cylindrical surface. NOTE - The axis of the test piece in which the prod uct was pressed should preferabl y be in the di 6.2 The top and bottom faces of the test piece shall be made plane and parallel by sawing (and grinding if necessary), and shall be perpendicular to
25、 the axis of the cylinder. The surface of the cylinder shall be free from visible defects. Measurements of the height at any two Points, using Vernier calipers, shall not differ by more than 0,2 mm. When one face of the test piece is placed on a plane surface and a set Square also in contact with th
26、e surface is brought into contact with any part of the periphery of the test piece, the gap between the side of the test piece and the Square shall not exceed 0,5 mm. 2 2 www.standards.org.au Standards Australiawww.standards.org.au Standards Australia The Standard is downloaded from Standard Sharin
27、g ISO 3187 :1989(E) 6.3 To ensure that the top and bottom ends of the test piece are flat over their entire surface, each end shall in turn be pressed onto a levelling plate which is lined with carbon Paper and hard filter Paper (0,15 mm in thickness). As an alternative to carbon Paper, the ends of
28、the test piece may be inked using a stamp pad. Test pieces that do not show two complete, clearly visible coloured impressions shall be re-ground. the period of heating and for the first hour after attaining con- stant temperature as indicated by the control thermocouple. Thereafter record the chang
29、es at 30 min intervals to completion of the test. 7.6 In a test in which the load is applied after the test piece has been maintained for a period at constant temperature, record the Change in height of the test piece and its temperature, starting when the load is applied, at 5 min inter- vals for t
30、he first hour and thereafter at 30 min intervals to com- pletion of the test. NOTE - It is also a straightedge. permissible to control the flatness of the surface with 7 Procedure 7.7 The Standard time for testing shall be 25 h. 7.1 Measure the height of the test piece to 0,l mm, and measure the inn
31、er and outer diameters of the test piece. Set up the test piece between the supporting and loading columns with the spacing discs, and adjust the measuring device to the correct setting. Position the assembly within the furnace. NOTES Extensions may ultiples of 25 h. be agreed as required, up to a m
32、aximum of 100 hin m 2 If tage the subsidence of the test piece exceeds some specified of its initial height, the test should be terminated. percen- 7.2 Apply a constant compressive load to the loading at one or other of the following stages i n the test : column a) at the moment when the furnace is
33、switched on, i.e, from ambient temperature; 8 Calculation of results b) after the test piece has been ma intai ned at the test tem perature for a given time ( minimum 1 h, maximum 4 h). 8.1 Load applied at ambient temperature 8.1.1 In a test in which the load is applied when the furnace is switched
34、on, use the results obtained in 7.5 to plot the curve C, (see figure 41, representing the percentage Change in the height of the test piece as a function of temperature, uncor- rected for the changes in length of the alumina tubes (5.3.1 and 5.3.2). Which alternative is used shall be stated in the t
35、est report. NOTE - Alternative b) is applicable if the behaviour of the material is only to be studied at the test temperature and allows the test piece to be exposed to a pre-test soak at the test temperature. The duration of this pre-treatment is stated in the test report. 7.3 The total load appli
36、ed to the test piece, including the mass of the moving column and the associated disc, shall be such as to generate in the test piece a stress with one of the following values, with tolerante limits of + 2 % : 8.1.2 Ascertain the changes in length, as a function of tem- perature, of a length of the
37、inner alumina tube (5.3.2) equal to the nominal height of the test piece. Express the value of these changes as percentages of the nominal height of the test piece, H, and with these percentages plot the correction curve C, shown in figure 4. a) for b) for dense shaped products: 0,2 N/mm2; 0,05 N/mm
38、? shaped insulating products: 8.1.3 Draw the corrected curve Cs as shown in figures in which, for any given temperature, AB = CD. 4and5 The total load used shall be rounded to the nearest 1 N. NOTE - Tests for unshaped products are presently outside the scope of this International Standard because t
39、here is no standard method for preparing test pieces. However, if such tests are carried out using the method described, the recommended loads are 8.1.4 Express the results in the form of a) a plot showing the percentage Change in height of the test piece (relative to its initial height) as a functi
40、on of temperature during the period of rising temperature (see figure 5); a) 0,l N/mm2 for dense unshaped products; b) 0,05 N/mm2 for unshaped insulating produ cts. b) a plot of the creep showing the percentage Change in height of the test piece (relative to its initial height) as a function of time
41、 during the period of constant temperature (see figure 5); 7.4 Raise the temperature of the furnace at such a rate that the regulating thermocouple (sec 5.4.2) indicates a rate of rise of temperature of between 4,5 K/min and 5,5 K/min. c) a table of the creep showing the percentage Change in height
42、of the test piece (relative to its initial height) at the moment when the constant temperature was reached and at intervals of 5 h thereafter; NOTE - UP to a temperature of 500 OC, a 10 K/min maY be used. heating rate of up to 7.5 In a test in which the load is applied when the furnace is switched o
43、n, record the changes in the height of the test piece and its temperature, at intervals not greater than 5 min during d) the total creep of testing. value between the 5th and the 25th hour 3 3 www.standards.org.au Standards Australia 3 www.standards.org.au Standards Australia ISO 3187 : 1989 (EI NOT
44、E - If the material began to deform before the test temperature was reached, such deformation should be referred to in the test report. This deformation is the percentage Change in the height of the test piece (relative to its initial height), which occurs between the temperature where the maximum o
45、n the expansion curve was observed and the test temperature. c) a reference to this International Standard, i.e., “Deter- mination of creep in compression in accordance with ISO 3187”; d) the description of the material tested ma nufacturer, type, batch n u mber, etc. 1; (for example e) if aPPl ica
46、ble, item 1 brick ); the number of tests performed on each 8.2 Load applied at test temperature In a test in which the load is applied after the test piece has been maintained for a period at constant temperature, express the creep results in the following form, for which a correction for the expans
47、ion of the alumina tube is not required : f) the Position and orientation of the test original brick or shape; piece in the 9) the type of furnace used; a) a plot of the creep showing the percentage Change in height of the test piece (relative to its initial height) as a func- tion of time during th
48、e period when the load was applied; h) the than air nature of the atmosphere in the furnace (if other 1; i) the heating rates employed; b) a table of the creep showing the percentage Change in height of the test piece (relative to its initial height) at the moment when the load was applied and at in
49、tervals of 5 h thereafter; the test temperature; k) whether the load was applied when the furnace was switched on or after a period of exposure to the test temperature; c) the total of testing . creep value between the 5th and the 25th hour 1) if applicable, the duration of exposu temperature before the load was ap pl ied; re to the test 9 Test report m) the load applied; The test report shall include the following particulars : n) the period for whi ch the load was applied, or the percenta ge defo Irrnation at which the test was termi na