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1、DRAFT FOR DEVELOPMENT DD ENV 993-11:1997 Dense shaped refractory products Part 11: Determination of resistance to thermal shock ICS 81.080 Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:51:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI DD ENV 993-11:1997 This
2、 Draft for Development, having been prepared under the direction of the Sector Board for Materials and Chemicals, was published under the authority of the Standards Board and comes into effect on 15 December 1997 BSI 03-1999 ISBN 0 580 28750 5 National foreword This publication is not to be regarded
3、 as a British Standard. It is being issued in the Draft for Development series of publications and is of a provisional nature because it is considered that further experience is required in its application before it is converted into a British Standard. It should be applied on this provisional basis
4、, so that information and experience of its practical application may be obtained. Comments arising from the use of this Draft for Development are requested so that UK experience can be reported to the European organization responsible for its conversion into a European Standard. A review of this pu
5、blication will be initiated 2 years after its publication by the European organization so that a decision can be taken on its status at the end of its three-year life. The commencement of the review period will be notified by an announcement in Update Standards. According to the replies received by
6、the end of the reviewed period, the responsible BSI Committee will decide whether to support the conversion into a European Standard, to extend the life of the prestandard or to withdraw it. Comments should be sent in writing to the Secretary of BSI Technical Committee RPI/1, Refractory products and
7、 materials, at 389 Chiswick High Road, London W4 4AL, giving the document reference and clause number and proposing, where possible, an appropriate revision of the text. Cross-references The British Standards which implement international or European publications referred to in this document may be
8、found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. Please note: the UK submitted a negative vote at the Formal vote stage, for this prestandard. Summary of pages Th
9、is document comprises a front cover, an inside front cover, pages i and ii, the ENV title page, pages 2 to 5 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendm
10、ents issued since publication Amd. No.DateComments Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:51:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI DD ENV 993-11:1997 BSI 03-1999i Contents Page National forewordInside front cover Foreword2 Text of EN 993-113
11、Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:51:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:51:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EUROPEAN PRESTA
12、NDARD PRNORME EUROPENNE EUROPISCHE VORNORM ENV 993-11 September 1997 ICS 81.080 Descriptors: Refractory materials, shape refractories, dense shaped refractory products, tests, determination, thermal shock resistance English version Dense shaped refractory products Part 11: Determination of resistanc
13、e to thermal shock Mthodes dessai des produits rfractaires faonns denses Partie 11: Dtermination de la rsistance au choc thermique Prfverfahren fr dichte geformte feuerfeste Erzeugnisse Teil 11: Bestimmung der Temperaturwechselbestndigkeit This European Prestandard (ENV) was approved by CEN on 30 Au
14、gust 1997 as a prospective standard for provisional application. The period of validity of this ENV is limited initially to three years. After two years the members of CEN will be requested to submit their comments, particularly on the question whether the ENV can be converted into a European Standa
15、rd. CEN members are required to announce the existence of this ENV in the same way as for an EN and to make the ENV available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the ENV) until the final decision about t
16、he possible conversion of the ENV into an EN is reached. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CE
17、N European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1997 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. ENV 993-11:1997 E Lic
18、ensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:51:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ENV 993-11:1997 BSI 03-1999 2 Foreword This European Prestandard has been prepared by Technical Committee CEN/TC 187 “Refractory products and materials”, the secreta
19、riat of which is held by BSI. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to announce this European Prestandard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxe
20、mbourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. EN 993 “Methods of test for dense shaped refractory products” consists of 18 Parts: Part 1: Determination of bulk density, apparent porosity and true porosity; Part 2: Determination of true density; Part 3: Tes
21、t methods for carbon-containing refractories; Part 4: Determination of permeability to gases; Part 5: Determination of cold crushing strength; Part 6: Determination of modulus of rupture at ambient temperature; Part 7: Determination of modulus of rupture at elevated temperatures; Part 8: Determinati
22、on of refractoriness-under-load; Part 9: Determination of creep in compression; Part 10: Determination of permanent change in dimensions on heating; Part 11: Determination of resistance to thermal shock (ENV); Part 12: Determination of pyrometric cone equivalent; Part 13: Specification for pyrometri
23、c cones; Part 14: Determination of thermal conductivity (hot wire, cross-array); Part 15: Determination of thermal conductivity (hot wire, parallel); Part 16: Determination of resistance to sulfuric acid; Part 17: Determination of bulk density of granular material (mercury method); Part 18: Determin
24、ation of bulk density of granular material (water method). Contents Page Foreword2 Introduction3 1Scope3 2Normative references3 3Definitions3 4Principle3 5Apparatus3 6Test Pieces4 7Procedure4 8Expression of results4 9Test report4 Table 1 Type of heating condition3 Licensed Copy: London South Bank Un
25、iversity, London South Bank University, Tue Dec 12 05:51:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ENV 993-11:1997 BSI 03-19993 Introduction Thermal shock of refractory materials placed in furnaces is influenced by three items: brick dimensions; heating/cooling conditions; material properties Th
26、ermal shock tests usually intend to test material properties. This is done by standardizing brick dimensions and heating conditions. In this way, a relative order of the quality of different types of bricks can be established. However, in case of thermal shock, this can lead to complications in the
27、field of engineering. The major complication is that, depending on the type of heating conditions, various material properties are involved. This can be best illustrated on the basis of thermal stress parameters which are a measure for critical crack initiation. Table 1 Type of heating condition Whe
28、re: 1 Scope This European Prestandard specifies the method for determining the resistance to thermal shock of dense shaped refractory materials by the air quenching method which proved to give the most reliable results as compared with the behaviour of the refractories placed in furnace linings. 2 N
29、ormative Reference This European Prestandard incorporates by dated or undated reference provisions from other publications. These normative references are cited at the appropriate places in the text and in the publicatons listed hereafter. For dated references, subsequent amendments or revisions of
30、any of these publications, apply to this European Prestandard only when incorporated in it by amendment or revison. For undated references the latest edition of the publication referred to applies. EN 993-6, Methods of test for dense shaped refractory products Determination of modulus of rupture at
31、ambient temperature. 3 Definitions For the purpose of this European Prestandard, the following definitions apply: 3.1 thermal-shock resistance is the resistance of refractory bricks to damage caused by sudden temperature changes between 950 C and room temperature due to air blowing 3.2 measure of th
32、ermal-shock resistance is the number of quenchings withstood under the conditions of this test 4 Principle The test piece is homogeneously heated to 950 C in an electric furnace, then removed, placed on a steel plate and exposed to air blowing. After quenching, the test piece is subjected to a stres
33、s of 0,3 MPa in a bending machine. This cycle is repeated until failure of the test piece. The resistance to thermal shock is defined by the number of cycles withstood by the test piece before breaking. 5 Apparatus electrically heated furnace, capable of maintaining a temperature 950 C 25 C thermoco
34、uple for use for temperatures in excess of 1 000 C drying oven heating cabinet for preheating at 250 C to 300 C blowing device with a 8 mm diameter nozzle of 5 mm length three point bending device according to EN 993-6 Hot face conditionStress parameter Example sudden temperature jump /filling of me
35、tallurgical vessels constant heat flow into brick ./furnace preheating constant heating rate /(. Cp) ./controlled preheating maximum allowable deformation coefficient of expansion thermal conductivity bulk density Cpspecific heat Licensed Copy: London South Bank University, London South Bank Univers
36、ity, Tue Dec 12 05:51:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ENV 993-11:1997 4 BSI 03-1999 steel plate of 400 mm 250 mm 20 mm with pins to determine the location of the test piece under the blast; according to the dimensions of the test-piece, the pins will be located in such a manner that th
37、e air jet blows at the intersection of the diagonals of the test-piece on cooling 6 Test pieces 6.1 Number of test pieces Unless a different number of test pieces has been agreed upon, one test piece shall be taken from each item. 6.2 Preparation of test pieces 6.2.1 Shape The test pieces shall have
38、 the dimensions of a quarter-standard brick, i.e. 114 mm 64 mm 64 mm. They shall be sawn or ground from bricks. NOTEThe use of other shapes may be agreed by the parties, but the results will not be directly comparable with those obtained using the test-pieces stated above. The test pieces shall be p
39、repared with great care so that the brick texture is not damaged. The location in the bricks from which the test pieces are to be taken shall be agreed upon. 6.2.2 Drying of the test pieces Dry the test pieces at 110 C 5 C to constant mass. Constant mass is obtained when the change in mass after two
40、 successive periods of one hour drying, is not more than 0,1 %. Protect test pieces from moisture before testing. 7 Procedure 7.1 Heating 7.1.1 Place the test pieces on one of their long faces into a heating cabinet previously heated to between 250 to 300 C and keep them at this temperature for, at
41、least, four hours. 7.1.2 Put the test pieces into the furnace at 950 C 25 C. The temperature of the furnace is measured with a thermocouple positioned over the centre of the basal area of the furnace approximately 20 mm above the test pieces. Immediately after the door of the furnace has been closed
42、, the temperature should not be less than 750 C. 7.1.3 The heat capacity of the furnace shall be sufficient for the temperature to rise again to 950 C within 15 to 30 min after placing the first test piece into the furnace. After the temperature has risen to 950 C, the test pieces shall remain in th
43、e furnace for a further 45 min. 7.2 Cooling Remove a test piece from the furnace using insulated iron tongs and place its long face on the steel plate, taking care that the nozzle of the air-blowing device and the centre of the upper face are aligned, with the help of the locating pins. The distance
44、 between the nozzle and the test piece shall be 100 mm. Blow compressed air on the test piece for five minutes, the pressure at the nozzle shall be constant and equal to 0,1 MPa 0,01 MPa. Be sure that the compressed air is at room temperature and does not contain moisture likely to concentrate in dr
45、oplets. Always expose the same face of the test piece to the blast. NOTEIf conditions remain in accordance with 7.1 and 7.2, more than one test-piece may be simultaneously or successivley tested. 7.3 Measurement 7.3.1 After quenching, the test piece is submitted to a bending strength of 0,3 MPa 0,05
46、 MPa gradually and without shock. 7.3.2 The distance between supports shall be 100 mm. The thrust column and the supports shall have radius of 5 mm. NOTEIf the test piece breaks, the test is completed. 7.3.3 If the test piece withstands the bending stress, place it again into the furnace at 950 C an
47、d start the same cycle. Continue the test until the test piece breaks in the bending test or breaks up into two or more pieces under the cooling blast. The test shall be ended when the test piece has withstood thirty quenchings. 7.3.4 Should it be necessary to interrupt the test, the test pieces sha
48、ll be maintained in the heating cabinet at 250 to 300 C after the last quenching. When testing is resumed, the test pieces shall be placed immediately in the furnace at 950 C 25 C. 8 Expression of results Express the resistance to thermal shock of the product as the number of quenching cycles withst
49、ood by the test piece before failure. 9 Test report The test report shall include the following information: a) a reference to this European Prestandard; b) designation of the tested material (manufacturer, type, batch number,.); c) the number of tested items; d) the number of test pieces per item; Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:51:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ENV 993-11