1、Methods of test for Dense shaped refractory products Part 12. Determination of pyrometric cone equivalent (refractoriness) The European Stanard EN 993-12 : 1997 has the status of a British Wdarci ICs 81.080 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW 1 BS EN ,993-12 : 1997
2、 BS 1902 : Section 5.2 : 1997 STD-BSI BS EN 793-LZ-ENGL 1997 Lb24bb7 Ob31470 742 BS EN 993-12 : 1997 Committees responsible for this British Standard The preparation of this British Standard was entrusted by Technical Committee RPV1, Refractmy products and materials, to Subcommittee RPI/Ul, Sampling
3、 and physical testing of refractry materials, upon which the folowing bodies were represented: British Ceramic Research Ltd. British Industrial Ceramic Manufacturers Association British Metallurgical Plant Constructors Association British Steel Industry British Vermiculite Association Refractories A
4、ssociation of Great Britain Refractory Contractors Association Society of Glass Technology This British Standard, having been prepared under the direction of the Sector Board for Materiais and Chemicals, was published under the authority of the Standards Board and comes into effect on 15 August 1997
5、 O BSI 1997 Amendments issued since publication Amd.No- ID temperature of collapse The temperature at which the tip of a pyrometric reference cone reaches the level on which the base of the cone is mounted when the cone is heated at a specified rate under specified conditions. Page 3 EN 993-12 : 199
6、7 4 Principle Test pieces of refractoqy materiais or products are raised in temperature, under specified conditions, alongside pyrometric reference cones of known refractoriness, and their behaviour is compared with that of the reference cones. 5 Apparatus 6.1 Furnace 6.1.1 The fumace used for the d
7、etermination may be cylindrical or rectangular, and either verical or horizontal. 6.1.2 Under the test conditions, the difference in temperature between the coldest spot and the hottest sgot of the space occupied by the stand, the test pieces and the pyrometric reference cones shall not ekceed 10 “C
8、 (equivaient to approximately one-half of a reference cone number: see EN 993-13). NOTE 1. In order that this requirement is met when pyrometric reference cones of height 30 mm are used (the conventional height), a cylindrical furnace should have a chamber of at least 80 mm useful diameter and a rec
9、tangular furnace should have a dhamber at least 60 mm in height and 100 mm in width. NOTE 2. In order to minimize the effects of any irregular temperature distribution in the furnace, it may be convenient to arrange for the stand to be kept in motion relative to the furnace during the determination,
10、 e.g. by rotating the stand about a vertical axis. The uniformity of temperature shail be verified from time to time. NOTE 3. The uniformity can be measured by means of thermocouples or by the use of pyrometric reference cones. 6.1.3 The furnace shall be capable of reaching the required temperature
11、at the rakes of increase specified in 9.2 and9.3. 6.1.4 The atmosphere in the furnace shall contain free oxygen at ali times. NOTE. Certain furnaces (for example, certain types of furnace fired with hydrocarbon gas and oxygen) are not suitable for this method of determination because of the high con
12、tent of reducing gases or water vapour in their atmospheres. 6.1.6 In the case of a gas-fired furnace, complying with 6.1.4, the pyrometric reference cones and the test pieces shail be protected from any direct action of the fiame and from any turbulence of the hot gases. 6.2 Pyrometric reference co
13、nes 6.2.1 The pyrometric reference cones used should preferably conform to the requirements of EN 993-13. 6.2.2 Alternatively, other pyrometric cones may be used, provided thak a) the manufacturer of the cones has stated their respective reference temperatures; b) the cones conform to those referenc
14、e temperatures within the tolerance permitted in EN 993.13; NOTE. This condition may be deemed to be satisfied if the manufacturer of the cones has declared that they conform to this tolerance; otherwise, they should be tested in accordance with clause 7 of EN 993-13 : 1995. O BSI 1997 STDmBSI BS EN
15、 773-12-ENGL 1717 W LbZLIbb7 Ob31LI7b 3b0 H Page 4 EN 993-12 : 1997 c) the manufacturer of the cones has specified the angle at which the leading edge is to be mounted (see 8.2) and the rates at which the cones are to be heated (see 9.3); d) if the authority carrying out the determjnation is distinc
16、t from that for whom it is carried out, the type of reference cone to be used shall be agreed between the parties concerned 6.3 Stand for the pyrometric reference cones and the test pieces 6.3.1 The refractory stand for the pyrometric reference cones and the test pieces consists, depending upon the
17、type of furnace used, of a rectangdar plate or a disc of refractory material having adequately plane and parallel faces. 6.3.2 The stand and the refractory cement used for securing the pyrometric reference cones and the test pieces to the stand shall be such that up to the test temperature there is
18、no reaction between these items and the pyrometric reference cones or the test pieces. 6 Test pieces 6.1 Size and shape Each test piece shall have a shape geometrically similar to that of the pyrometric reference cones being used. Each test piece shall have a height not less than 100 %, and not more
19、 than 120 %, of the height of the reference cones being used. 6.2 Preparation of test pieces 6.2.1 General Where possible, test pieces from shaped and prefired unshaped products shall be cut in accordance with 6.2.2. If test pieces mot be cut, they shall be moulded from ground materiai in accordance
20、 with 6.2.3. Test pieces from powder and granular materials shall always be moulded in accordance with 6.2.3. 6.2.2 Cut test pieces 6.2.2.1 Test pieces from bricks and shapes shall be cut with a saw and dressed with a grinding wheel. Any skin of fired materials shall be removed 6.2.2.2 Samples of un
21、shaped materia,l.s such as plastic remries, ramming materiais, refractoqy mortars and refractory castables shall be shaped and fired in a manner appropriate to the material and its condition of use; the nring temperature shall be stated in the test report. W pieces shall then be cut from the red mat
22、eriai wih a saw and dressed with a grinding wheel. Any skin of fired material shall be removed. 6.2.2.3 In preparing a cut test piece (see 6.2.2.1 and 6.2.2.2), it is advisable, as a first step, to cut a rectangular prism of a suitable size (15 mm X 15 mm X 40 nun, for a test piece of 30 mm height)
23、and, if the refractory material has a coarse or friable texture, to impregnate it with a suitable resin giving less than 0,5 % ash (e.g. Canada baisam). This rectangular prism is then cut and dressed. 6.2.3 Moulded test pieces 6.2.3.1 Test pieces for raw materials and prepared unshaped refractory ma
24、terials, and for those shaped refractory products from which test pieces cannot be cut in accordance with 6.2.2, shal be prepared in accordance with 6.2.3.2 to 6.2.3.6. 6.2.3.2 Crush the sample or samples selected, so that ali the material passes through a test sieve with a nominal aperture of 2 mm
25、and conforming to the requirements of IS0 565. Using a procedure agreed between the parties to the test, reduce the quantity of test material to that appropriate for the preparation of the number of test pieces required. Grind the reduced quantity of sample in a suitable mortar until it entirely pas
26、ses through a test sieve of nominal aperture 180 pm conforming to the requirements of IS0 565. During this grinding, sieve the material frequently in order not to produce an excess of very fine powder. NOTE. Less than 50 % of the ground sample should pass bugh a test sieve with a nominal aperture si
27、ze of 90 pm, except in the case of raw materiais containing, as received, a percentage of fines larger than 50 %. 6.2.3.3 At ali stages, crushing and grinding should be carried out so as to avoid the introduction of extraneous material. At all stages, mixing should be carefully carried out so that t
28、he contents of the test pieces are tniiy representative of the samples. 6.2.3.4 Knead the powdered sample with water to which has been added, if the test material is lean, an organic binder having a maximum of 0,5 % ash content. If the test material reacts with water, use another suitable liquid ins
29、tead of water. 6.2.3.6 Mould the test pieces in suitable moulds. NOTE. A suitable mould is illustrated in the annex A. 6.2.3.6 lbt pieces prepared from raw materiais that are subject to considerable modincation during reheating shall then be stabilized by heating before their refr-adoriness is deter
30、mined In particular, clays should be calcined at approximately lo00 OC; after calcination, the test pieces sha comply with the requirements of 6.1. O BSI 1997 7 Selection of pyrometric reference cones Select pyrometric reference cones in the following numbers: For a circular For a test stand rectang
31、uiar test stand a) Corresponding to the estimated or anticipated refractoriness number of the material under test This is based on the result of a preliminary test; see 9.4 b) With a refractoriness number one lower than in a) c) With a 2 2 1 2 refractoriness number one higher than in a) 1 2 8 Prepar
32、ation of test stand Page 6 EN 993-12 : 1997 9.4 Stop the heating as soon as the tip of one of the test pieces touches the stand or, if the test pieces cannot be observed during the test, at a temperature corresponding to the pyrometric resistance of the pyrometric reference cone most nearly correspo
33、nding to the estimated or expected refractoriness number of the test materiai, as determined by means of an opticai pyrometer or a thermocouple in a preliminary test on a pyrometric reference cone with that refractoriness number. 9.6 Remove the stand from the funiace and note the number of the pyrom
34、etric reference cone that has bent over to the same degree as each of the test pieces, or, if appropriate, the numbers of the two pyrometric reference cones that have bent over, one a little more and one a little less than each of the test pieces. 9.6 Repeat the test if any one or more of the test p
35、ieces or pyrometnc reference cones have not bent in the normal manner, or if the difference in the bending of the two test pieces is greater than onehaif of a wrometric reference cone number. *“ 9.7 Express the pyrometric cone equivalent of the test material by the number or numbers of the pyrometri
36、c reference cone or cones as described in 9.6. 10 %st report - ._ - 8.1 Place two test pieces and the pyrometric reference cones selected in accordance with clause 7 me test repod shall include the following infomon: e * * on the test stand, arranging them in accordance with figure 1, depending upon
37、 whether the test stand is a) the name of the testing estabiishment; b) the date of the test; c) a reference to this European Standard, i.e. determinaiion of refractoriness in accordance with EN 993-12; d) the product or material tested (mufacturer, type, batch number); e) whether the test piece was
38、 cut or moulded; f) if appropriate, the temperature of any preiiminasy ring of the test piece (see 6.2.3.1 and 6.2.3.6); B circular or rectangular. Mow sufficient room for the cones to be unobstructed when they bend. Fix the base of each cone to the stand with refractmy cement. 8.2 The test pieces a
39、nd the pyrometric reference cones shall be positioned so that an edge leans outwards at the angie to the vertical specified by the manufacturer of the reference cones (see figure 2). 9 Procedure g) the pyrometric cone equivalent of the test piece and the type of pyrometric reference cones used, for
40、example IS0 170 or EN 99313; h) in the case of reDeated tests. ail the resuts lace the test stand, with the test pieces and the pyrometric reference cones attached to it, in the uniform temperature zone of the furnace. 9.2 Over a period of 1,5 h to 2 h, raise the temperature of the furnace to 200 “C
41、 below the estimated refractoriness temperature of the test material. 9.3 Then raise the temperature at a constant rate of 2,5 Umin or, 86.2.2 applies, at the rate specified by the manufacturer of the cones. Maintain the rate of heating so that at any moment the deviation from the specified temperat
42、ure rise curve is less than 10 “C. NOTE. The rate of heating of 2,5 Wmin corresponds to a time interval of about 8 min between the collapse of two pyrometric reference cones with consecutive numbers; see EN 993-13. obtained and the mean result. O BSI 1997 STD-ES1 BS EN 973-LZ-ENGL 1997 lb2Libb9 Ob3L
43、Li98 133 W Page 6 EN 993-12 : 1997 N-1 C N+l C 10 N+l N C N-1 1 N+l N C N-1 Symbols C Cone (test cone) N-1 Reference pyrometric cones expected to span the setting N+l temperature of the test cone Figure 1. Examples of the arrangement of cones on the test stand Figure 2. Pyrometric reference cone sho
44、wing typical angle of leaning outside edge O BSI 1997 STD-BSI BS EN 993-12-ENGL 1997 m Lb24bb7 Ob3L477 07T m Page 7 EN 993-12 : 1997 Annex A (informative) mical mould for test pieces Left-hand half of split mould NOTE . Make of copper or steel, preferably hardened, and grind important surfaces. Dime
45、nsions in millimetres marks k404 /, - Hardwood Mould assembly NOTE. Index marks show the height of the cone. Figure A.l Qpical mould for moulded test pieces BS EN 993-12 : 1997 List of references See nationai foreword. * m * O BSI 1997 STD-BSI BS EN 773-12-ENGL 1777 lb2Libb9 Ob3l50L 55 m BS EN BS 19
46、02 : Section 5.2 : 1997 993-12 : 1997 BSI 389 Chiswick High Road London w4 4AL BSI - British Standards Institution BSI is the independent national body responsible for preparing British standards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Ro
47、yal Charter. Contract requirements A British Stanard does not purport to include all the necessary provisions of a contract. Users of British standards are responsible for their correct application. Revisions British standards are updated by amendment or revision. Users of British Standards should m
48、ake sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone nding an inaccmy or ambiguity while using this British Stanhd would inform the Secretary of the responsible technical commit
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