1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 13947:2011Metallic powders Testmethod for the determinationof non-metallic inclusionsin metal powders using apowder-forged specimenBS ISO 13947:2011 BRITISH STANDARDNation
2、al forewordThis British Standard is the UK implementation of ISO 13947:2011. Itsupersedes BS ISO 13947:2007 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee ISE/65, Sintered metal components.A list of organizations represented on this committee can beobt
3、ained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2011ISBN 978 0 580 75875 1ICS 77.160Compliance with a British Standard cannot confer immunity fromlegal obligations.This Bri
4、tish Standard was published under the authority of theStandards Policy and Strategy Committee on 31 December 2011.Amendments issued since publicationDate Text affectedBS ISO 13947:2011Metallic powders Test method for the determination of non-metallic inclusions in metal powders using a powder-forged
5、 specimenPoudres mtalliques Dtermination de la teneur en inclusions non mtalliques dans les poudres mtalliques laide dune prouvette forge de poudre ISO 2011Reference numberISO 13947:2011(E)Second edition2011-12-01ISO13947INTERNATIONAL STANDARDBS ISO 13947:2011ISO 13947:2011(E)COPYRIGHT PROTECTED DOC
6、UMENT ISO 2011All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body
7、 in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in Switzerlandii ISO 2011 All rights reservedBS ISO 13947:2011ForewordISO (the International Organization for Standardizati
8、on) 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 to be re
9、presented 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 Standards a
10、re 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 Internation
11、al 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 13947 was prepa
12、red by Technical Committee ISO/TC 119, Powder metallurgy, Subcommittee SC 2, Sampling and testing methods for powders (including powders for hardmetals).This second edition cancels and replaces the first edition (ISO 13947:2007), of which it constitutes a minor revision.ISO 13947:2011(E) ISO 2011 Al
13、l rights reserved iiiBS ISO 13947:2011BS ISO 13947:2011INTERNATIONAL STANDARD ISO 13947:2011(E)Metallic powders Test method for the determination of non-metallic inclusions in metal powders using a powder-forged specimenSAFETY PRECAUTIONS This International Standard does not purport to address all o
14、f the safety problems, if any, associated with its use. It is the responsibility of the user of this International Standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use.1 ScopeThis International Standard specifies a me
15、tallographic method for determining the non-metallic inclusion level in metal powders using a powder-forged specimen. The test method covers repress powder-forged test specimens in which there has been minimal lateral flow (1 %). The core region of the powder-forged test specimen contains no porosit
16、y detectable at 100 magnification.This test method can also be used to determine the non-metallic inclusion content of powder-forged steel parts. However, in parts where there has been a significant amount of material flow, the near-neighbour separation distance needs to be changed, or the inclusion
17、 sizes agreed between the parties need to be adjusted.This test method is not suitable for determining the non-metallic inclusion level of parts that have been forged such that the core region contains porosity. At the magnification used for this test method, residual porosity is hard to distinguish
18、 from inclusions. Too much residual porosity makes a meaningful assessment of the inclusion population impossible.This test method can be applied to materials that contain manganese sulfide (admixed or prealloyed), provided the near-neighbour separation distance is changed from 30 m to 15 m.2 Normat
19、ive referencesThe following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO/TR 14321:1997, Sintered metal ma
20、terials, excluding hardmetals Metallographic preparation and examinationASTM B796, Standard test method for nonmetallic inclusion content of powders intended for powder forging (P/F) applicationsASTM E3, Standard guide for preparation of metallographic specimensASTM E768, Standard guide for preparin
21、g and evaluating specimens for automatic inclusion assessment of steel3 PrinciplesA section representing the core region of the test specimen (part) is cut from the test piece (part) prior to metallographic grinding and polishing (mounting the section is optional but strongly recommended).The polish
22、ed sample is examined microscopically at a magnification of 100 and a note is made of inclusions greater than a predetermined size. ISO 2011 All rights reserved 1BS ISO 13947:2011The maximum Ferets diameter is used to determine inclusion size. A Ferets diameter is a caliper diameter, as illustrated
23、in Figure 1.The fragmented nature of some inclusions means that their size determination is somewhat complicated. The concept of near-neighbour separation shall be used in determining inclusion size. According to this concept, if an inclusion is within a certain distance of its neighbouring particle
24、s, it is considered a member of an inclusion cluster or agglomerate. Detected features within 30 m of one another are considered part of the same inclusion. The concept is illustrated schematically in Figure 2.The non-metallic inclusion level of the test specimen (part) is reported as the number of
25、inclusions, per 100 mm2, greater than or equal to the predetermined size.4 Significance and use4.1 The non-metallic inclusion level of ferrous powders is an indication of powder cleanliness. In pressed and sintered ferrous powder metallurgy (PM) materials, the extensive porosity present masks the ef
26、fect of inclusions on mechanical properties. In contrast, the properties of a PM material processed to near pore-free density are strongly influenced by the composition, size, size distribution, and location of non-metallic inclusions.4.2 The test for non-metallic inclusions in fully dense steel par
27、ts is useful as a characteristic to classify or differentiate one grade of powder or batch of parts from another, and a lot-to-lot quality comparison of powders intended for powder forging.4.3 A significant amount of variation in non-metallic inclusion content will occur if the powder used to form t
28、he test specimen (part) does not meet the required quality standards for non-metallic inclusion content, or processing of the test specimen (part) has been carried out under conditions that do not permit oxide reduction or allow oxidation of the test specimen (part), or both.4.4 The use of the near-
29、neighbour concept offers a more conservative estimate of the inclusions: it will overestimate rather than underestimate them.5 Apparatus5.1 Equipment, for the metallographic preparation of test specimens.5.2 Metallographic microscope, permitting observation and measurement up to a magnification of 1
30、00 using light with a wavelength of 544 nm (green filter), an objective lens with a magnification ranging from 8 to 12,5, and a numerical aperture between 0,16 and 0,20.NOTE Defining the light optics used is important because this determines the features that will be resolved, and all detected featu
31、res are included in the assessment of inclusion size.6 Test piece6.1 For the evaluation of the non-metallic inclusion content of a powder that is intended for use in powder-forging applications, the powder shall be mixed with an appropriate amount of graphite and lubricant and compacted to a specifi
32、ed green density. The test method covers repress powder-forged test specimens in which there has been minimal lateral flow (1 %) so the diameter of the green compact shall be such, relative to the diameter of the forging die, that this requirement is met.ISO 13947:2011(E)2 ISO 2011 All rights reserv
33、edBS ISO 13947:20116.2 A metallographic specimen shall be removed from the powder-forged test specimen (part), austenitized and quenched. Hardening of the specimen facilitates sample preparation by preventing smearing of soft inclusions and scratching.6.3 The polished surface of the specimen (part)
34、to be examined shall be not less than 350 mm2in area. Multiple sections are permitted in order to obtain the necessary area for measurement on small parts.6.4 The polished surface shall be parallel to the direction of working; that is, parallel to the direction of travel of the forging tools, and sh
35、all represent the core region of the test specimen (part).7 Procedure7.1 Preparation of specimensIn polishing the specimens, it is highly important that a clean polish be obtained and that the inclusions not be pitted, dragged or obscured. It is therefore recommended that the procedures described in
36、 ASTM E3 and ASTM E768 be followed. Automated grinding and polishing procedures are recommended. Examine specimens in the as-polished condition, free of the effects of any prior etching (if used). ISO/TR 14321:1997 shall be followed.7.2 Measurement of non-metallic inclusion content7.2.1 Survey at le
37、ast 350 mm2of the surface of the polished specimen at a magnification of 100 using light with a wavelength of 544 nm (green filter), an objective lens with a magnification ranging from 8 to 12,5 and a numerical aperture between 0,16 and 0,20.7.2.2 Size the detected inclusions on the basis of near-ne
38、ighbour separation.Features within 30 m (0,03 mm) of one another (within 3 mm of one another at 100 magnification) are considered to be part of the same inclusion.7.2.3 For individual features of less than 30 m in size, three such features within 30 m of one another are required to constitute an inc
39、lusion aggregate, when the near-neighbour separation principle is used.7.2.4 Add an individual feature of less than 30 m in size to an inclusion larger than 30 m, provided both features are within 30 m of one another, when the near-neighbour separation principle is used. Examples are given in Figure
40、 2.7.2.5 Measure and record the number of inclusion particles, according to the principle of near-neighbour separation and sized using the maximum Ferets diameter, that are greater than or equal to 30 m in length, greater than or equal to 100 m in length, and greater than or equal to 150 m in length
41、.In addition to the use of the near-neighbour separation concept to size the inclusions, the size of the individual particles can be measured.7.2.6 If the inclusions are also sized individually, the inclusions are sized using the maximum Ferets diameter as in 7.2.5. Results from the use of the near-
42、neighbour separation concept will usually be more conservative (more larger inclusions).ISO 13947:2011(E) ISO 2011 All rights reserved 3BS ISO 13947:20118 Test reportThe test report should include the following information:a) a reference to this International Standard, i.e. ISO 13947:2011;b) the num
43、ber of non-metallic inclusions per 100 mm2that are greater than or equal to 30 m in length, greater than or equal to 100 m in length, or greater than or equal to 150 m in length;c) whether the particles were sized individually, in addition to using the near-neighbour separation principle;d) the tota
44、l area examined.9 Precision and biasThe precision and bias that can be expected through use of this test method are currently under review by ASTM Subcommittee B09.11 on near-full-dense PM materials.Key1 maximum Ferets diameter2 Ferets diameterFigure 1 Schematic illustration of Ferets diameterISO 13
45、947:2011(E)4 ISO 2011 All rights reservedBS ISO 13947:2011Key1 maximum Ferets diameterFigure 2 Schematic illustration of “near-neighbour” concept and maximum Ferets diameterISO 13947:2011(E) ISO 2011 All rights reserved 5BS ISO 13947:2011ISO 13947:2011(E) ISO 2011 All rights reservedICS 77.160Price
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