BS EN 24003-1993 Permeable sintered metal materials - Determination of bubble test pore size《不密封烧结金属材料 气泡试验孔隙尺寸的测定》.pdf

1、BRITISH STANDARD BS EN 24003:1993 ISO 4003:1977 Permeable sintered metal materials Determination of bubble test pore size The European Standard EN24003:1993has the status of a British Standard UDC 6621.762.5:669-492.2:620.1:539.217BSEN24003:1993 This British Standard, having been prepared under the

2、directionof the Iron and Steel Standards Policy Committee, waspublished under the authorityof the Standards Boardand comes into effect on 15June1993 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference ISM/65 Special announcement in BSI News January 1993

3、ISBN 0 580 21940 2 Cooperating organizations The European Committee for Standardization (CEN), under whose supervision this European Standard was prepared, comprises the national standards organizations of the following countries: Austria Oesterreichisches Normungsinstitut Belgium Institut belge de

4、normalisation Denmark Dansk Standardiseringsraad Finland Suomen Standardisoimisliito, r.y. France Association franaise de normalisation Germany Deutsches Institut fr Normung e.V. Greece Hellenic Organization for Standardization Iceland Technological Institute of Iceland Ireland National Standards Au

5、thority of Ireland Italy Ente Nazionale Italiano di Unificazione Luxembourg Inspection du Travail et des Mines Netherlands Nederlands Normalisatie-instituut Norway Norges Standardiseringsforbund Portugal Instituto Portugus da Qualidade Spain Asociacin Espaola de Normalizacin y Certificacin Sweden St

6、andardiseringskommissionen i Sverige Switzerland Association suisse de normalisation United Kingdom British Standards Institution Amendments issued since publication Amd. No. Date CommentsBSEN24003:1993 BSI 10-1999 i Contents Page Cooperating organizations Inside front cover National foreword ii For

7、eword 2 1 Scope and field of application 3 2 Reference 3 3 Principle 3 4 Definition 3 5 Apparatus 4 6 Procedure 5 7 Expression of results 5 8 Test report 5 Annex ZA (normative) Normative references to international publications with their relevant European publications 6 National annex NA (informati

8、ve) Committees responsible Inside back cover National annex NB (informative) Cross-reference Inside back cover Figure Bubble test assembly 4 Table Test liquids suitable for use with permeable metals 5BSEN24003:1993 ii BSI 10-1999 National foreword This British Standard has been prepared under the di

9、rection of the Iron and Steel Standards Policy Committee and is the English language version of EN24003:1993 Permeable sintered metal materials Determination of bubble test pore size, published by the European Committee for Standardization (CEN). It is identical with ISO4003:1977, published by the I

10、nternational Organization for Standardization (ISO). This British Standard supersedes BS5600-3.5:1979which is withdrawn and from which it differs by the addition of Annex ZA. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are res

11、ponsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, theEN title page, pages2 to6, an inside back cover and a back cover. Th

12、is 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.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 24003 April 1993 UDC 6621.762.5:669-492.2:620.1:539.217 Descriptors: Powder metallu

13、rgy, sintered products, porous metal, porosity, physical tests, bubble tests, pores, dimensional measurements English version Permeable sintered metal materials Determination of bubble test pore size (ISO 4003:1977) Matriaux en mtal fritt permable Dtermination de la dimension des pores Mthode bullos

14、copique (ISO 4003:1977) Durchlssige Sintermetalle Ermittlung der Porengre mittels Gasblasentest (ISO 4003:1977) This European Standard was approved by CEN on1993-04-02. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European S

15、tandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, Fren

16、ch, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, F

17、rance, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels

18、 1993 Copyright reserved to CEN members Ref. No. EN 24003:1993 EEN24003:1993 BSI 10-1999 2 Foreword In 1992, ISO4003:1977 Permeable sintered metal materials Determination of bubble test pore size was submitted to the CEN Primary Questionnaire procedure. Following the positive result of the CEN/CS Pr

19、oposal ISO4003:1977was submitted to the Formal Vote. The result of the Formal Vote was positive. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by October1993, and conflicting national standards sha

20、ll be withdrawn at the latest by October1993. According to the CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spa

21、in, Sweden, Switzerland, UnitedKingdom. NOTEThe European references to international publications are given in Annex ZA (normative).EN24003:1993 BSI 10-1999 3 1 Scope and field of application This International Standard specifies a method, known as the bubble test method, for the determination of th

22、e pore size of permeable sintered powder metallurgical materials, i.e. filters, porous bearings, porous electrodes and other parts with interconnected porosity. NOTEThe bubble test shall be considered as a quality control test and not as a test for defining filter grades or determining exact pore si

23、ze and pore size distribution. 2 Reference ISO 2738, Permeable sintered metal materials Determination of density and open porosity. 3 Principle Impregnation of a test piece with a test liquid. Immersion of the test piece in the test liquid and introduction of a gas (usually air) into the test piece

24、at gradually increasing pressure. Determination of the pressure at which bubbles are emitted from the surface of the test piece. Evaluation of the equivalent bubble test pore size by means of a mathematical formula. 4 Definition bubble test pore size the maximum equivalent capillary diameter in the

25、test piece which is calculated from the measured minimum pressure required to force the first bubble of gas through the test piece (under standardized conditions) impregnated with a liquid the first bubble of gas will form at the pore having the greatest throat, the throat being the narrowest sectio

26、n of this pore for calculation purposes, it is assumed that this bubble forms at the end of a capillary tube of circular cross-section which is initially filled with the same liquid of known surface tension for a circular capillary, the diameter is related to the bubble pressure by the equation: NOT

27、E 1The bubble test pore size corresponds to the minimum differential pressure at which constant bubbling first occurs. For this reason, this pressure is sometimes termed “minimum bubble pressure” or “first bubble point”. The corresponding capillary diameter is sometimes termed “maximum pore size” or

28、 “maximum pore diameter”, or “largest pore size”. However, the maximum pore size determined with this method may be the result of a single local defect, and therefore not representative of the pore population. NOTE 2As the gas pressure increases beyond the minimum bubble pressure (first bubble point

29、), different aspects of bubbling occur on the test piece. The pressure for a given aspect can lead to the definition of a conventional pore size. For example, the pressure for which a generalized bubbling occurs is frequently specified (foaming over the whole surface). These particular definitions s

30、hould be agreed between the supplier and the user. Moreover, the uniformity of distribution of pores approaching the maximum pore size may be observed by gradually increasing the gas pressure. Cracks and clogged areas are easily discerned by this operation. NOTE 3The bubble test does not constitute

31、a measurement of the maximum size of particle that the permeable test piece will pass (retentivity of a filter). A filter may be expected to retain all particles larger than the maximum pore size as defined by the bubble test; but, because of irregularity in shape of pores and other phenomena relate

32、d to the filtration process, the same filter will retain particles which are much smaller than the maximum pore size. The determination of the size of the largest non-deforming particle which can pass through the porosity requires time-consuming methods, for example a glass-bead test. For estimation

33、 purposes it is useful to take empirical factors, which are to be multiplied with the bubble test pore size calculated from equation (1). The factor is about0,4for porous metal made from uniform spherical particles; and about0,2for porous metal made from irregular particles. . . .(1) d 4 %p - = wher

34、e d is the capillary diameter corresponding to the bubble test pore size, in metres; * is the surface tension of the test liquid, in newtons per metre; %p is the differential pressure, in pascals, across the test piece under static conditions, i.e. %p = p g p l . . .(2) p g being the gas pressure, i

35、n pascals; p l being the pressure in the liquid at the level of bubble formation, in pascals: p l= 9,81 1 h . . .(3) where l is the density of the test liquid, in kilograms per cubic metre; h is the height of the surface of the test liquid, in metres, above the highest throat in the test piece.EN240

36、03:1993 4 BSI 10-1999 5 Apparatus 5.1 Dry and filtered gas (generally air) supply, at an adequate pressure. 5.2 Pressure regulator affording constant and precise control of the gas pressure, i.e. a gradual increase of the pressure at a predetermined rate, or a stepwise increase of pressure and the f

37、acility to maintain a constant pressure at each step. 5.3 Flow-meter, if required. 5.4 Device to measure the effective gas pressure, measuring to an accuracy of 1% (mechanical pressure gauge, or water or mercury manometer). This device shall be placed close to the bubble test cell, in order to facil

38、itate the simultaneous observation of the bubble appearance and the pressure value. 5.5 Assembly for observing the bubble appearance at the surface of the test piece, according to the shape of the test piece, and for ensuring that the test piece is completely saturated with the liquid, and immersed

39、under a constant depth of the liquid throughout the test. If the test piece is hollow or of a shape other than flat, it should be rotated with its major axis horizontal so that the whole surface is examined. 5.6 Test liquid, selected in relation to the kind of metal composing the test piece. Among p

40、ure liquids which wet metals perfectly, 95% ethanol, methanol, isopropanol or carbon tetrachloride are most generally employed (see the Table for properties). The test is carried out at room temperature(20 5 C). The surface tension, *, of the test liquid may be obtained from tables of physical const

41、ants. Figure Bubble test assemblyEN24003:1993 BSI 10-1999 5 Table Test liquids suitable for use with permeable metals 6 Procedure The test piece shall be clean, dry and free from extraneous material and any trace of grease or similar substances likely to hinder the perfect and uniform wetting action

42、 of the test liquid. Impregnate the test piece completely with the test liquid. Insert it in the bubble test apparatus and maintain it fixed, immersed under the smallest depth of test liquid consistent with the convenient observation of the appearance of the bubbles. Measure this depth h (see the Fi

43、gure) and the temperature of the liquid. From an effective gas pressure of zero, increase the pressure regularly at a rate of between20and100Pa/s (according to the estimated pore size), while the surface of the test piece is under constant observation. In the case of a hollow cylindrical test piece,

44、 rotate it so that all of the surface is observed; in this case, increase the pressure in steps, each of from50to500Pa (according to the estimated pore size), so that each new pressure value is maintained whilst the surface is observed during the rotation. Note the first bubble pressure when a strin

45、g of bubbles occurs from one distinct point (or perhaps several distinct points at the same time). If there is a defect, the first bubble may appear in a zone remote from the upper surface. In this event, reduce the pressure and repeat the test after rotating the sample on its own axis; increase the

46、 pressure again incrementally. NOTE 1The test piece shall be impregnated to ensure the saturation of its open porosity. A vacuum impregnation in accordance with the requirements given in ISO2738is recommended. NOTE 2When a determination is repeated on the same sample, it is necessary to re-impregnat

47、e the sample totally before retesting. NOTE 3It is important that the test piece be properly sealed in the apparatus. If bubbles emerge from the proximity of the seals, the result shall be ignored and the test repeated with improved seals. NOTE 4When the test piece is composed of a layer of fine por

48、es supported on a base of coarser pores, the bubble test pore size characterizing the material is that of the fine pore layer. The test piece shall be tested in such a way that the bubbles appear at the surface of the fine pore layer. NOTE 5By agreement between user and supplier, pore sizes correspo

49、nding to other bubbling conditions may be determined as indicated in clause 4, note2. 7 Expression of results Calculate the bubble test pore size, using the formula in clause 4. Report the arithmetical mean of three determinations rounded to the nearest5%. 8 Test report The test report shall include the following information: a) reference to this International Standard; b) all details necessary for identification of the test sample; c) the liquid used; d) the rate of pressure increase; e) the position of the fir