DIN EN ISO 3954-2007 Powders for powder metallurgical purposes - Sampling (ISO 3954 2007) English version of DIN EN ISO 3954 2007-11《粉末冶金用粉末 取样》.pdf

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1、November 2007DEUTSCHE NORM English price group 8No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 77.160!$JJ:“1393923www

2、.din.deDDIN EN ISO 3954Powders for powder metallurgical purposes Sampling (ISO 3954:2007)English version of DIN EN ISO 3954:2007-11Pulver fr die Pulvermetallurgie Probenahme (ISO 3954:2007)Englische Fassung DIN EN ISO 3954:2007-11SupersedesDIN ISO 3954:1980-04www.beuth.deDocument comprises 13 pagesD

3、IN EN ISO 3954:2007-11 2 National foreword This standard was prepared by Technical Committee ISO/TC 119/SC 2 “Sampling and testing methods for powders (including powders for hardmetals)” and has been adopted as EN ISO 3954:2007 by Technical Committee CEN/SS M11 “Powder metallurgy” (Secretariat: CMC)

4、. The responsible German body involved in its preparation was the Normenausschuss Werkstofftechnologie (Materials Technology Standards Committee), Technical Committee NA 145-01-02 AA Probenahme und Prf-verfahren fr Pulver (einschlielich Pulver fr Hartmetalle). Amendments This standard differs from D

5、IN ISO 3954:1980-04 as follows: a) Clause 3 “Number of increments” has been modified. b) Clause 4 “Sampling” has been modified. Previous editions DIN ISO 3954: 1980-04 EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 3954September 2007ICS 77.160 Supersedes EN 23954:1993 English VersionPoudres p

6、our emploi en mtallurgie des poudres -chantillonnage (ISO 3954:2007)This European Standard was approved by CEN on 27 August 2007.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard

7、 without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other langu

8、age made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,F

9、rance, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR

10、NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2007 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 3954:2007: EPowders for powder metallurgical purposes - Sampling(ISO 3954:2007)Pulver fr die Pulvermetallurgie - P

11、robenahme(ISO 3954:2007)EN ISO 3954:2007 (E) 2 Contents Page Foreword 3 1 Scope 4 2 Terms and definitions 4 3 Number of increments. 5 3.1 Sampling during discharge in a continuous stream 5 3.2 Sampling from powders packaged in containers. 5 4 Sampling. 6 4.1 General 6 4.2 Sampling procedures 6 4.3 S

12、ample splitting . 8 Foreword This document (EN ISO 3954:2007) has been prepared by Technical Committee ISO/TC 119 “Powder metallurgy“ in collaboration with Technical Committee CEN/SS M11 “Powder metallurgy“, the secretariat of which is held by CMC. This European Standard shall be given the status of

13、 a national standard, either by publication of an identical text or by endorsement, at the latest by March 2008, and conflicting national standards shall be withdrawn at the latest by March 2008. This document supersedes EN 23954:1993. According to the CEN/CENELEC Internal Regulations, the national

14、standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Polan

15、d, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 3954:2007 has been approved by CEN as a EN ISO 3954:2007 without any modification. 3 EN ISO 3954:2007 (E) 1 Scope This International Standard specifies procedures for the s

16、ampling of powders for powder metallurgical purposes. lt also covers the splitting of the sample into the quantity required for testing. 2 Terms and definitions For the purposes of this document, the following terms and definitions apply (see also Figure 1). 2.1 lot quantity of powder processed or p

17、roduced under conditions that are presumed uniform 2.2 increment quantity of powder obtained by a sampling device at one time from a single lot 2.3 gross sample quantity of powder, adequate for the tests to be performed, consisting of all the increments taken from a single lot 2.4 composite sample b

18、lended entire gross sample or part thereof NOTE 1 Alternatively, it may be obtained by splitting the lot. NOTE 2 However it is obtained, it is essential that it be thoroughly blended. 2.5 test sample quantity of powder taken from the composite sample for determining a single property or for preparin

19、g test pieces NOTE It is normally taken by splitting the composite sample. 2.5.1 test portion definite quantity of powder drawn from the test sample (or, if both are the same, from the composite sample) and on which the test is carried out 2.5.2 test piece test specimen object of specified form prep

20、ared from a test sample EN ISO 3954:2007 (E)4Figure 1 Sampling scheme 3 Number of increments 3.1 Sampling during discharge in a continuous stream If the entire lot is discharged in a continuous stream through an opening, it may be sampled during discharge. In such a case, increments shall be taken a

21、t regular intervals during the entire discharge period. The number of increments shall depend on the accuracy desired. At least three increments shall be taken, one during the time taken to discharge the first third of the lot, one half-way through the discharge period and one during the time taken

22、to discharge the last third. 3.2 Sampling from powders packaged in containers Unless otherwise agreed, the number of containers listed in Table 1 shall be selected at random from the lot when samples are taken from powder packaged in containers. One or more increments shall be taken from every selec

23、ted container to provide a gross sample. If containers holding different quantities are included in the lot, the containers selected shall be from the lot and the number of increments taken from every selected container shall be in proportion to the content of the container. EN ISO 3954:2007 (E)5Tab

24、le 1 Sampling from containers Number of containers in the lot Number of containers from which increments shall be taken 1 to 5 All 6 to 11 5 12 to 20 6 21 to 35 7 36 to 60 8 61 to 99 9 100 to 149 10 150 to 199 11 200 to 299 12 300 to 399 13 For every additional 100 containers or portion thereof in t

25、he lot, one additional container shall be sampled. 4 Sampling 4.1 General Increments shall be taken in such a manner that the composite sample represents the lot as accurately as possible. NOTE Demixing may occur at any time when a batch of powder is set in motion, for example when filling container

26、s, emptying containers, during transportation or if subjected to vibration during storage. All the surfaces of a sampling device that come into contact with the powder shall be smooth and clean. 4.2 Sampling procedures 4.2.1 General requirements The sampling procedure shall be such that the powder p

27、roperties are not changed. Whenever possible, procedure 4.2.2 should be preferred over procedure 4.2.3. 4.2.2 Sampling during discharge in a continuous stream The dimensions of the sampling container at right angles to the stream of powder shall exceed the cross-section of the stream by an ample mar

28、gin. They shall be large enough so that no overflow of powder occurs when collecting the sample. The sampling container shall be exposed to the powder stream and withdrawn in such a manner that all portions of the stream have an equal chance of entering it. NOTE The simplest method of achieving this

29、 is to move a container of rectangular cross-section across the stream at constant speed. The gross sample thus obtained shall be blended by rotating for 10 to 15 revolutions at 15 rpm to 30 rpm in order to obtain the composite sample. EN ISO 3954:2007 (E)64.2.3 Sampling from packaged containers usi

30、ng sampling thieves 4.2.3.1 Different types of sampling thief can be used. The length of the thief shall be such that it allows extraction of powder from all levels in the container. The design depends on the flow properties of the powder from which the sample is to be taken. One type of sampling th

31、ief is shown in Figure 2. Figure 2 Sampling thief 4.2.3.2 The sampling thief shown in Figure 2 is suitable only for loosely packed powder with a high flowability. lt comprises an inner and an outer tube with closed ends and longitudinal slit-shaped windows positioned so that they are opened and clos

32、ed successively as the tubes are twisted relative to each other. The tubes shall fit each other loosely enough for twisting not to be hindered by the largest particles encountered. The sampling thief shall be inserted all the way to the bottom of the container with the windows closed. It is recommen

33、ded that it be inserted in the direction that was vertical during transportation and storage. When the thief has reached the bottom, the windows shall be opened so that the thief is filled from bottom to top, after which the windows shall be closed and the thief withdrawn. The contents of the thief

34、shall be emptied into the gross sample container. If the depth of powder is greater than the height of the windows of the thief, more than one increment shall be taken so that the powder is sampled at every depth, the number of increments being a multiple of the ratio of the depth of the powder to t

35、he height of the windows. 4.2.3.3 A second type of sampling thief comprises a single tube with an open end. It is suitable for powders that remain inside the tube when it is withdrawn. This condition may be fulfilled by selecting a suitable tube diameter. This type of sampling thief shall be inserte

36、d slowly all the way to the bottom of the container. It is recommended that it be inserted in the direction that was vertical during transportation and storage. When the thief has reached the bottom, it shall be withdrawn and its contents emptied into the gross sample container. EN ISO 3954:2007 (E)

37、74.2.3.4 If demixing has occurred in the direction in which the thief is inserted, errors will occur if the thief does not withdraw an equal quantity from every stratum. To reduce the effect of demixing at right angles to the direction of thief insertion, the points of insertion shall be distributed

38、 as representatively as possible. For example, if several increments are taken from the contents of a single cylindrical container, the number of increments taken at each distance from the axis of the container shall be proportional to that distance. If only one increment is taken from the contents

39、of a cylindrical container, the thief shall be inserted at a distance from the centre equal to 0,7 of the radius of the container, provided the container was filled through an opening above the central axis of the container. If the opening was at another location, and in the case of non-cylindrical

40、containers, a place which is equally representative shall be chosen for sampling. 4.2.3.5 The gross sample thus obtained shall be blended by rotating for 10 to 15 revolutions at 15 rpm to 30 rpm in order to obtain the composite sample. 4.2.4 Sampling by splitting the lot The device and procedure men

41、tioned in 4.3 are used for splitting the lot. This method is generally suitable for small lots. 4.3 Sample splitting The device used for splitting samples shall be of the proper size for the amount of powder being split so that handling losses may be disregarded and contamination minimized. The foll

42、owing devices have been found suitable: a spinning riffler; see Figure 3; a sample splitter; see Figure 4; a rotary sample splitter; see Figure 5; a rotating-cone splitter; see Figure 6. EN ISO 3954:2007 (E)8Key 1 powder hopper 2 vibratory chute 3 spinning riffler Figure 3 Spinning riffler (schemati

43、c) Figure 4 Sample splitter EN ISO 3954:2007 (E)9Key 1 feed 2 speed of rotation 15 rpm to 50 rpm 3 cutter 4 rejected material 5 sample Figure 5 Rotary sample splitter EN ISO 3954:2007 (E)10Key 1 feed 2 speed of rotation 60 rpm 3 rejected material 4 sample Figure 6 Rotating-cone splitter EN ISO 3954:2007 (E)11