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1、INTERNATIONAL STANDARD 3954 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION .MEXCflYHAPOflHAR OPrAHC13AUCIII ITO CXAHnAPTH3Al(CIM.ORGANISATION INTERNATIONALE DE NORMALISATION Powders for powder metallurgical purposes - Sampling Poudres pour emploi en mtftallurgie des poudres - lkhantillonnage First e
2、dition - 1977-02-15 UDC 621.762 : 669-492.2 : 620.113 Ref. No. IS0 3954-1977 (E) E ul ii Descriptors : powder metallurgy, metal powder, sampling, tests. % B Price based on 5 pages Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical
3、Standards 1/9972545001 Not for Resale, 04/27/2007 19:59:10 MDTNo reproduction or networking permitted without license from IHS -,-,- FOREWORD IS0 (the International Organization for Standardization) is a worldwide federation of national standards institutes (IS0 member bodies). The work of developin
4、g International Standards is carried out through IS0 technical committees. Every member body interested in a subject for which a technical committee has been set up has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO,
5、 also take part in the work. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the IS0 Council. International Standard IS0 3954 was developed by Technical Committee ISO/TC 119, Powd
6、er metallurgical materials and products, and was circulated to the member bodies in October 1975. It has been approved by the member bodies of the following countries : Austria Japan Canada Mexico Czechoslovakia Poland Egypt, Arab Rep. of Portugal France Romania Germany Spain Italy Sweden Turkey Uni
7、ted Kingdom U.S.A. U.S.S.R. Yugoslavia No member body expressed disapproval of the document. 0 International Organization for Standardization, 1977 l Printed in Switzerland Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standar
8、ds 1/9972545001 Not for Resale, 04/27/2007 19:59:10 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD IS0 3954-1977 (E) Powders for powder metallurgical purposes - Sampling 1 SCOPE AND FIELD OF APPLICATION This International Standard specifies procedure
9、s for the sampling of powders for powder metallurgical purposes. It also covers the splitting of the sample into the quantity required for testing. 2 REFERENCES IS0 78, Guide on the form for standards for chemical products and for methods of chemical analysis. IS0 3081, Iron ores - Increment samplin
10、g - Manual method. 3 DEFINITIONS The following definitions are in accordance with IS0 3081 and IS0 78. 3.1 lot : A quantity of powder processed or produced under conditions which are presumed uniform. 3.2 increment : A quantity of powder obtained by a sampling device at one time from a single lot. 3
11、.3 gross sample : The quantity of powder consisting of all the increments taken from a single lot. 3.4 composite sample : The blended entire gross sample or a representative part thereof. Alternatively it may be obtained by splitting the lot. However it is obtained, it should be thoroughly blended.
12、3.5 test sample : A quantity of powder taken from the composite sample for determining a single property or for preparing the test pieces. It should normally be taken by splitting the composite sample. 3.5.1 test portion : A definite quantity of powder drawn from the test sample (or, if both are the
13、 same, from the composite sample) and on which the test is carried out. 3.5.2 test piece : An object of specified form prepared from a test sample. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for R
14、esale, 04/27/2007 19:59:10 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 3954-1977 (E) Lot Increments Gross sample (Blending) Composite sample Test samples Test portions non Test pieces (Determination) FIGURE 1 - Scheme of sampling 4 NUMBER OF INCREMENTS 4.1 Sampling
15、from powders packaged in containers Unless otherwise agreed, the number of containers listed in the table 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 selected container to provide a gross sample.
16、 If containers holding different quantities are included in the lot, the containers selected shall be representative of the lot and the number of increments taken from every selected container shall be in proportion to the content of the container. 4.2 Sampling during discharge in continuous stream
17、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 at regular intervals during the entire discharge period. The number of in- 2 Number of containers in Number of containers from the lot which increm
18、ents shall be taken It0 5 all 6to 11 5 12to 20 6 21 to 35 7 36 to 60 61 to 99 100 to 149 150 to 199 200 to 299 300 to 399 8 9 10 11 12 13 For every additional 100 containers or portion thereof in the lot, one additional container shall be sampled. crements shall depend on the accuracy desired. At le
19、ast three increments shall be taken, one shortly after dis- charging commences, one half-way through the discharge period and one shortly before discharging is completed. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards
20、 1/9972545001 Not for Resale, 04/27/2007 19:59:10 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 3954-1977 (E) 5 SAMPLING 5.1 General Increments shall be taken in such a manner that the composite sample will be representative of the lot as accurately as possible. NOTE
21、- Demixing may occur at any time when a batch of powder is set in motion, for example when filling containers, emptying containers, during transportation and if subjected to vibrations during storage. All the surfaces of a sampling device which comes into contact with the powder shall be smooth and
22、clean. 5.2 Sampling procedures The sampling procedure shall be such that the powder properties are not changed. 5.2.1 Sampling by splitting the lot The device and procedure mentioned in 5.3 are used for splitting the lot. 5.2.2 Sampling during discharge in continuous stream The dimensions of the sam
23、pling container at right angles to the stream of powder shall exceed the cross-section of the stream by an ample margin. 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 simples
24、t method of achieving this is to move a container of rectangular cross-section across the stream at constant speed. 5.2.3 Sampling with sampling thieves 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 con
25、tainer. The design depends on the flow properties of the powder from which the sample is to be taken. Two examples are shown in figures 2 and 3. 5.2.3.1 The sampling thief according to figure 2 is suitable only for loosely packed powder with a high flowability. It comprises an inner and an outer tub
26、e with closed end 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 thief sh
27、all 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 which 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
28、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. 5.2.3.2 The sampling thief according to figure 3 comprises a single tube with opened end. It is suitable for powders which remain inside the tube when
29、it is withdrawn. This condition may be fulfilled by selecting a suitable tube diameter. The 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 which was vertical during transportation and storage. When the thief
30、has reached the bottom, it shall be withdrawn and its contents emptied into the gross sample container. NOTES 1 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
31、 being a multiple of the ratio of the depth of the powder to the height of the window. 2 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. 3 To reduce the effect of demixing at right angles
32、 to the direction of the 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 the container sha
33、ll be proportional to that distance. If only one increment is to be taken from the content of a cylindrical container, the thief shall be inserted at a distance from the centre equal to 0.7 of the radius. 5.3 Sample splitting The device for splitting samples shall be of the proper size for the amoun
34、t of powder being split so that handling losses may be disregarded and contamination minimized. The following devices have been found suitable : 1) quartering device; 2) sample splitter; 3) rotary sample splitter; 4) rotating cone sample splitter. Examples are shown in figures 4 to 7. 3 Copyright In
35、ternational Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 19:59:10 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 3954-1977 (E) t- FIGURE 2 -Sampling thief B FIGURE 3 -S
36、ampling thief FIGURE 4 - Quartering device 4 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 19:59:10 MDTNo reproduction or networking permitted without license from IHS -,-,- IS
37、0 3954-1977 (E) FIGURE 5 - Sample splitter 15 to 50 redmin w J t Sample Reject FIGURE 6 - Rotary sample splitter Sample FIGURE 7 - Rotating cone sample splitter 5 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 19:59:10 MDTNo reproduction or networking permitted without license from IHS -,-,-