BS EN ISO 3954-2007 Powders for powder metallurgical purposes - Sampling《粉末冶金用粉末 取样》.pdf

1、BRITISH STANDARDBS EN ISO 3954:2007Powders for powder metallurgical purposes SamplingThe European Standard EN ISO 3954:2007 has the status of a British StandardICS 77.160g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g4

2、0g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN ISO 3954:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 28 September 2007 BSI 2007ISBN 978 0 580 56264 8National forewordThis British Standard is the UK implemen

3、tation of EN ISO 3954:2007. It supersedes BS EN 23954:1993 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee ISE/65, Sintered metal components.A list of organizations represented on this committee can be obtained on request to its secretary.This publicat

4、ion does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARDNORME EUROPENNEEURO

5、PISCHE NORMEN ISO 3954September 2007ICS 77.160 Supersedes EN 23954:1993 English VersionPowders for powder metallurgical purposes - Sampling (ISO3954:2007)Poudres pour emploi en mtallurgie des poudres -chantillonnage (ISO 3954:2007)Pulver fr die Pulvermetallurgie - Probenahme (ISO3954:2007)This Europ

6、ean 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 without any alteration. Up-to-date lists and bibliographical references conce

7、rning 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 language made by translationunder the responsibility of a CEN member into its own l

8、anguage 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,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, L

9、uxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2007 CEN All rig

10、hts of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 3954:2007: EForeword 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 metal

11、lurgy“, the secretariat of which is held by CMC. 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 March 2008, and conflicting national standards shall be withdrawn at the latest by March 2008. This

12、 document supersedes EN 23954:1993. According to the CEN/CENELEC Internal Regulations, the national 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

13、, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, 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 mod

14、ification. EN ISO 3954:2007Reference numberISO 3954:2007(E)INTERNATIONAL STANDARD ISO3954Second edition2007-09-01Powders for powder metallurgical purposes Sampling Poudres pour emploi en mtallurgie des poudres chantillonnage EN ISO 3954:2007ii iiiForeword ISO (the International Organization for Stan

15、dardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right

16、 to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International S

17、tandards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an

18、International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 39

19、54 was prepared by Technical Committee ISO/TC 119, Power metallurgy, Subcommittee SC 2, Sampling and testing methods for powders (including powders for hardmetals). This second edition cancels and replaces the first edition (ISO 3954:1977), which has been technically revised. EN ISO 3954:2007blank1P

20、owders for powder metallurgical purposes Sampling 1 Scope This International Standard specifies procedures for the sampling 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 thi

21、s document, the following terms and definitions apply (see also Figure 1). 2.1 lot quantity of powder processed or produced 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, ade

22、quate for the tests to be performed, consisting of all the increments taken from a single lot 2.4 composite sample blended 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.

23、2.5 test sample quantity of powder taken from the composite sample for determining a single property or for preparing 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

24、 composite sample) and on which the test is carried out 2.5.2 test piece test specimen object of specified form prepared from a test sample EN ISO 3954:20072 Figure 1 Sampling scheme 3 Number of increments 3.1 Sampling during discharge in a continuous stream If the entire lot is discharged in a cont

25、inuous stream through an opening, it may be sampled during discharge. In such a case, increments shall be taken at 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

26、to discharge the first third of the lot, one half-way through the discharge period and one during the time taken 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

27、when samples are taken from powder packaged in containers. One or more increments shall be taken from every selected 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 tak

28、en from every selected container shall be in proportion to the content of the container. EN ISO 3954:20073Table 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

29、 149 10 150 to 199 11 200 to 299 12 300 to 399 13 For every additional 100 containers or portion thereof in the 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. NO

30、TE Demixing may occur at any time when a batch of powder is set in motion, for example when filling containers, 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 cle

31、an. 4.2 Sampling procedures 4.2.1 General requirements The sampling procedure shall be such that the powder properties 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 c

32、ontainer at right angles to the stream of powder shall exceed the cross-section of the stream by an ample margin. 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 th

33、at all portions of the stream have an equal chance of entering it. NOTE The simplest method of achieving this 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

34、rpm in order to obtain the composite sample. EN ISO 3954:20074 4.2.3 Sampling from packaged containers using 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

35、depends on the flow properties of the powder from which the sample is to be taken. One type of sampling thief 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 ou

36、ter tube with closed ends and longitudinal slit-shaped windows positioned so that they are opened and closed 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

37、thief shall be inserted all the way to the bottom of the container with the windows closed. It is recommended 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

38、bottom to top, after which the windows shall be closed and the thief withdrawn. The contents of the thief 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 samp

39、led at every depth, the number of increments being a multiple of the ratio of the depth of the powder to the 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 cond

40、ition may be fulfilled by selecting a suitable tube diameter. This type of sampling thief shall be inserted 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 bo

41、ttom, it shall be withdrawn and its contents emptied into the gross sample container. EN ISO 3954:200754.2.3.4 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 demi

42、xing at right angles to the direction of thief insertion, the points of insertion shall be distributed 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 t

43、he container shall be proportional to that distance. If only one increment is taken from the contents 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 cent

44、ral axis of the container. If the opening was at another location, and in the case of non-cylindrical 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

45、order to obtain the composite sample. 4.2.4 Sampling by splitting the lot The device and procedure mentioned 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

46、of powder being split so that handling losses may be disregarded and contamination minimized. The following 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

47、:20076 Key 1 powder hopper 2 vibratory chute 3 spinning riffler Figure 3 Spinning riffler (schematic) Figure 4 Sample splitter EN ISO 3954:20077Key 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 3954:20078 Key 1 feed 2 speed o

48、f rotation 60 rpm 3 rejected material 4 sample Figure 6 Rotating-cone splitter EN ISO 3954:2007blankBS EN ISO 3954:2007BSI389 Chiswick High RoadLondonW4 4ALBSI British Standards InstitutionBSI is the independent national body responsible for preparing British Standards. It presents the UK view on st

49、andards in Europe and at the international level. It is incorporated by Royal Charter.RevisionsBritish Standards are updated by amendment or revision. Users of British Standards should make 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 finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front