1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationSintered metal materials, excluding hardmetals Preparation of samples for chemical analysis for determination of carbon contentBS EN ISO 7625:2012National forewordThis British St
2、andard is the UK implementation of EN ISO 7625:2012. It supersedes BS EN ISO 7625:2010 which is withdrawn.The UK participation in its preparation was entrusted to Technical CommitteeISE/65, Sintered metal components.A list of organizations represented on this committee can be obtained onrequest to i
3、ts secretary.This publication does not purport to include all the necessary provisions of acontract. Users are responsible for its correct application. The British Standards Institution 2012Published by BSI Standards Limited 2012ISBN 978 0 580 75120 2ICS 77.160Compliance with a British Standard cann
4、ot confer immunity fromlegal obligations.This British Standard was published under the authority of the StandardsPolicy and Strategy Committee on 31 December 2012.Amendments issued since publicationAmd. No. Date Text affectedBRITISH STANDARDBS EN ISO 7625:2012EUROPEAN STANDARD NORME EUROPENNE EUROPI
5、SCHE NORM EN ISO 7625 November 2012 ICS 77.160 Supersedes EN ISO 7625:2010English Version Sintered metal materials, excluding hardmetals - Preparation of samples for chemical analysis for determination of carbon content (ISO 7625:2012) Matriaux mtalliques fritts, lexclusion des mtaux-durs - Prparati
6、on des chantillons pour analyse chimique en vue du dosage du carbone (ISO 7625:2012) Sintermetalle, ausgenommen Hartmetalle - Vorbereitung von Proben fr die chemische Analyse zur Bestimmung des Kohlenstoffgehaltes (ISO 7625:2012) This European Standard was approved by CEN on 1 December 2012. CEN mem
7、bers are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on applicat
8、ion to the CEN-CENELEC 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 translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Manage
9、ment Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
10、 Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 B
11、russels 2012 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 7625:2012: EBS EN ISO 7625:2012EN ISO 7625:2012 (E) 2 Contents Page Foreword 3BS EN ISO 7625:2012EN ISO 7625:2012 (E) 3 Foreword This document (EN ISO 7625:2012) has
12、been prepared by Technical Committee ISO/TC 119 “Powder metallurgy“. 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 May 2013, and conflicting national standards shall be withdrawn at the latest b
13、y May 2013. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN ISO 7625:2010. According to the CEN/CENELEC In
14、ternal Regulations, the national standards organisations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland,
15、 Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endorsement notice The text of ISO 7625:2012 has been approved by CEN as a EN ISO 7625:2012 without any modification.
16、BS EN ISO 7625:2012ISO 7625:2012(E)IntroductionThe chemical analysis of sintered metal materials, excluding hardmetals, is carried out as it would be for solid metals, by using existing standard methods. However, as these sintered materials very often contain carbonaceous constituents, the correct d
17、etermination of carbon content (free or total) requires that certain precautions be taken when preparing the sample for analysis from components.Samples prepared in accordance with this International Standard may also be suitable for chemical analysis for other elements.iv ISO 2012 All rights reserv
18、edBS EN ISO 7625:2012Sintered metal materials, excluding hardmetals Preparation of samples for chemical analysis for determination of carbon content1 ScopeThis International Standard specifies methods for preparing a sample from one or more sintered parts to be analysed for free or total carbon cont
19、ent. Combined carbon is determined as the difference between total and free carbon. This standard covers the preparation of samples for the determination of carbon by a chemical method, i.e. combustion in oxygen and measurement of the carbon dioxide produced, in accordance with ISO 437. It does not
20、cover the preparation of samples for carbon determination by physical methods, such as metallography or spectroscopy.2 Normative referencesThe following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated refe
21、rences, the latest edition of the referenced document (including any amendments) applies.ISO 437, Steel and cast iron Determination of total carbon content Combustion gravimetric methodISO 2738, Sintered metal materials, excluding hardmetals Permeable sintered metal materials Determination of densit
22、y, oil content, and open porosity3 PrincipleEliminate any impregnated or surface carbon using the procedures in Clause 5. Prepare samples for analysis by fragmentation or machining, taking care not to lose any free carbon.4 MaterialsThis International Standard applies to parts in which carbon is uni
23、formly distributed and present in the forms shown in Table 1. It does not apply to parts in which the carbon is not uniformly distributed throughout the part, including those parts with carburized or decarburized surfaces.In instances where the carbon is not uniformly distributed, for example a case
24、-hardened part, the method of selecting the sample should be agreed upon between the supplier and the purchaser.The presence of carbonaceous materials in the pores or on the surface of the part to be analysed interferes with the determination of carbon, see Table 2.Table 1 Forms of carbon that can b
25、e determined by chemical analysisForm of carbon Typical materials CommentsCombined carbon (as carbides or in solid solution)Carbon-containing steels and super-alloysDetermined as the difference between total and free carbonFree carbon Bronze and steel containing graph-ite; material impregnated with
26、a graphite-containing liquidDetermined by combustion of the residue of selective dissolution of the metal in the sample.Total carbon Determined by direct combustion of the sampleINTERNATIONAL STANDARD ISO 7625:2012(E) ISO 2012 All rights reserved 1BS EN ISO 7625:2012ISO 7625:2012(E)Table 2 Origins o
27、f carbonaceous material and feasibility of carbon determination by chemical methodsCarbonaceous material Origin Feasibility1 Liquid or semi-liquid organic substances on the surface or in the poresSizing lubricant, quenching oil, impregnating lubricant, cutting fluid, greaseCarbon determination is po
28、ssible only when these organic substances are totally eliminated by the method described in Clause 52 Waxes and wax-like substances Sizing lubricant, corrosion protec-tive3 Deposits of carbon on the parts Sintering, heat treatment4 Solid organic substances, for example, plastics materials on the sur
29、face or in the poresSealant material In general, it is not possible to elimi-nate these substances, and determi-nation of carbon is not possible5 Procedure5.1 Removal of interfering carbonaceous material5.1.1 GeneralCarbonaceous materials (see Table 2) that affect the carbon determination shall be r
30、emoved from the part or parts to be analysed as specified in 5.1.2 and 5.1.3.5.1.2 Impregnated organic substances in the pores or on the surface (see Cases 1 and 2 in Table 2) shall be removed by Soxhlet degreasing with an appropriate solvent, in accordance with ISO 2738. The solvent used shall be s
31、tated.NOTE When the impregnated liquid contains fine carbon particles, for example colloidal graphite, it is possible that not all of these particles are removed by Soxhlet degreasing. In such a case, the determination of free carbon and total carbon is invalid. Nevertheless, the calculation of comb
32、ined carbon is still valid if the free carbon and total carbon are determined on the same part or parts after degreasing.5.1.3 Surface deposits of carbon (see Case 3 in Table 2) shall be removed by mechanical treatment.5.2 Final preparationThe sample for analysis shall consist of small fragments of
33、a size appropriate to the analysis method to be used, prepared by one of the following methods: crushing in a mortar made of a material which does not alter the sample composition; drilling, milling or turning. Such machining shall be performed dry by using hardmetal or ceramic tools. Care shall be
34、taken to avoid overheating, oxidation and contamination of the fragments. Where drilling is used, the part shall be drilled through completely and the distribution of drilling holes shall be uniform over the whole surface of the part. If the part is too thick, the holes shall be drilled to the middl
35、e from both faces of the part.Where crushed or machined fragments contain fine particles (for example free graphite), care shall be taken not to lose these particles during handling.Where segregation is expected to be a problem, the entire sample should be analysed after being divided into a suitabl
36、e number of test portions. The carbon content is then calculated as the average of the results from each portion.In general, a sufficient quantity of fragments, representative of the part or parts, shall be prepared. The samples for analysis shall be kept in a container that is tightly sealed, in or
37、der to avoid contamination.2 ISO 2012 All rights reservedBS EN ISO 7625:2012ISO 7625:2012(E)6 PrecisionWhen the degreasing is carried out according to ISO 2738 as stated in 5.1.2, the carbon content after oil removal can be considered suspect if the repeatability is greater than 5 % and the reproduc
38、ibility is greater than 10 % at the 95 % confidence level. ISO 2012 All rights reserved 3BS EN ISO 7625:2012This page deliberately left blankThis page deliberately left blankBSI is the independent national body responsible for preparing British Standards and other standards-related publications, inf
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