1、August 2013 Translation by DIN-Sprachendienst.English price group 8No part of this translation 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
2、77.160!%(5“2052918www.din.deDDIN EN ISO 4491-4Metallic powders Determination of oxygen content by reduction methods Part 4: Total oxygen by reduction-extraction (ISO 4491-4:2013);English version EN ISO 4491-4:2013,English translation of DIN EN ISO 4491-4:2013-08Metallpulver Bestimmung des Sauerstoff
3、gehaltes durch Reduktionsverfahren Teil 4: Gesamt-Sauerstoffgehalt durch Reduktionsextraktion (ISO 4491-4:2013);Englische Fassung EN ISO 4491-4:2013,Englische bersetzung von DIN EN ISO 4491-4:2013-08Poudres mtalliques Dosage de loxygne par les mthodes de rduction Partie 4: Oxygne total par rduction-
4、extraction (ISO 4491-4:2013);Version anglaise EN ISO 4491-4:2013,Traduction anglaise de DIN EN ISO 4491-4:2013-08SupersedesDIN ISO 4491-4:1990-06www.beuth.deDocument comprises pagesIn case of doubt, the German-language original shall be considered authoritative.1108.13 DIN EN ISO 4491-4:2013-08 2 A
5、comma is used as the decimal marker. National foreword This document (EN ISO 4491-4:2013) has been prepared by Technical Committee ISO/TC 119 “Powder metallurgy” in collaboration with Technical Committee CEN/TC SS M 11 “Powder metallurgy” (Secretariat: CCMC). The responsible German body involved in
6、its preparation was the Normenausschuss Werkstofftechnologie (Technology of Materials Standards Committee), Working Committee NA 145-01-02 AA Probenahme und Prfverfahren fr Pulver (einschlielich Pulver fr Hartmetalle). The DIN Standard corresponding to the International Standard referred to in this
7、document is as follows: ISO 4491-1 DIN ISO 4491-1 Amendments This standard differs from DIN ISO 4491-4:1990-06 as follows: a) the standard has been editorially revised. Previous editions DIN ISO 4491-4: 1990-06 National Annex NA (informative) Bibliography DIN ISO 4491-1, Metallic powders Determinati
8、on of oxygen content by reduction methods General guidelines EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 4491-4 May 2013 ICS 77.160 Supersedes EN 24491-4:1993English Version Metallic powders - Determination of oxygen content by reduction methods - Part 4: Total oxygen by reduction-extra
9、ction Poudres mtalliques - Dosage de loxygne par les mthodes de rduction - Partie 4: Oxygne total par rduction-extraction (ISO 4491-4:2013) Metallpulver - Bestimmung des Sauerstoffgehaltes durch Reduktionsverfahren - Teil 4: Gesamt-Sauerstoffgehalt durch Reduktionsextraktion (ISO 4491-4:2013) This E
10、uropean Standard was approved by CEN on 2 April 2013. CEN members 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 c
11、oncerning such national standards may be obtained on application 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
12、 into its own language and notified to the CEN-CENELEC Management 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, Franc
13、e, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, 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 KOM
14、ITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2013 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 4491-4:2013: E(ISO 4491-4:2013) Contents Page EN ISO 4491-4:2013 (E) DIN EN ISO 4491-4:2013-08 2 Foreword
15、 3Introduction .4 1 Scope 5 2 Normative references 5 3 Principle 5 4 Apparatus and materials .6 5 Test portion 6 6 Procedure .7 6.1 General 7 6.2 Blank test and calibration .7 6.3 Test 8 7 Expression of results 8 7.1 Permissible tolerances 8 7.2 Final result 8 8 Test report 8 Annex A (informative) E
16、xamples of conditions of extraction for selected metal powders .9 Foreword This document (EN ISO 4491-4:2013) has 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 o
17、r by endorsement, at the latest by November 2013, and conflicting national standards shall be withdrawn at the latest by November 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 responsib
18、le for identifying any or all such patent rights. This document supersedes EN 24491-4:1993. 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, Croatia, Cyprus, C
19、zech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United King
20、dom. Endorsement notice The text of ISO 4491-4:2013 has been approved by CEN as EN ISO 4491-4:2013 without any modification. “EN ISO 4491-4:2013 (E) DIN EN ISO 4491-4:2013-08 3 IntroductionThe determination of the oxygen content of metallic powders is of the utmost importance in many fields of powde
21、r metallurgy.The standard methods described in ISO 4491-2 and ISO 4491-3 do not give the total oxygen content of the sample, as some oxygen-containing constituents are not reduced by hydrogen.Therefore, a standard method for the determination of the total oxygen content is needed. The most frequentl
22、y used method is reduction-extraction. It can be carried out with various commercially available instruments working according to different principles of extraction and measurement.It should be emphasized that the results of the analysis depend on the type of equipment used and on the test parameter
23、s selected. However, as indicated in Clauses 3 to 6, it is always possible, for a given type of metal powder, to optimize the test conditions to obtain reproducible and accurate results with any of the commercially available instruments, provided they are designed for testing the metal powder consid
24、ered.It is not possible to standardize one or more particular instruments. However, certain basic points of procedure are recommended for the analysis of metallic powders (see Clause 6).NOTE The reduction-extraction method is also applicable to nitrogen determination and certain instruments permit s
25、imultaneous measurement of oxygen and nitrogen contents. However, the determination of nitrogen is not covered by this International Standard.EN ISO 4491-4:2013 (E) DIN EN ISO 4491-4:2013-08 4 1 ScopeThis part of ISO 4491 specifies a method for the determination of the total oxygen content of metall
26、ic powders by reduction-extraction at high temperature.By agreement, this method is also applicable to the determination of the total oxygen content of sintered metal materials.The method is applicable to all powders of metals, alloys, carbides, and mixtures thereof which are non-volatile under the
27、test conditions. The sample may be in powder or compact form.The analysis is carried out on the powder as supplied, but the method is not applicable if the powder contains a lubricant or binder. If such substances are present, the method may be used only if they can first be completely removed by a
28、method not affecting the oxygen content of the powder.This part of ISO 4491 is to be read in conjunction with ISO 4491-1.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, on
29、ly the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 4491-1, Metallic powders Determination of oxygen content by reduction methods Part 1: General guidelines3 PrincipleA test portion of the sample is heated in a gr
30、aphite crucible at high temperature, either under vacuum or in a flow of an inert carrier gas. Oxygen in the sample is converted to oxides of carbon. These are extracted and transformed completely to either carbon monoxide or carbon dioxide, which is determined by a suitable gas analysis method.The
31、methods used in practice to determine the total oxygen content have the following features:a) Environment in the reaction chamber: Vacuum or flow of inert gas (nitrogen, argon, helium).b) Graphite crucible: Individual, i.e. used only for one test portion, or cumulative, i.e. the same crucible is use
32、d for the analysis of several successive test portions.EN ISO 4491-4:2013 (E) DIN EN ISO 4491-4:2013-08 5 c) Reaction medium: Dry, i.e. the test portion alone is poured into the graphite crucible, the reduction being carried out in the solid state if the metal being analysed does not melt, or metal
33、bath, i.e. in order to accelerate the reduction of certain metals it is advisable to prepare first a bath of a fusible metal (for example platinum, tin, iron, nickel) capable of dissolving both carbon and the metal in the test portion.d) Heating: Continuous, i.e. the test portion is introduced into
34、the crucible previously heated to the reaction temperature, the reduction taking place over a fixed period of time, of the order of several minutes, or pulse, i.e. the cold crucible containing the test portion is heated by injecting, over a period of a few seconds, a high-power pulse of energy, redu
35、ction taking place very rapidly at the high peak temperature (up to 3 000 C) which results.e) Determination of oxygen:Several methods for measuring either CO or CO2are available. In both cases a chemical conversion device is used to ensure that the oxygen to be determined is transformed completely i
36、nto either CO or CO2. The analytical methods commonly used are volumetric (for carbon monoxide), chromatography (for carbon monoxide), infrared absorption (for carbon monoxide), thermal conductivity (for carbon monoxide and carbon dioxide), coulometry (for carbon dioxide).4 Apparatus and materialsTh
37、e main elements of an apparatus suitable for determining the oxygen content of a metallic powder are the following: crucibles, machined from high purity graphite; a device to degas the graphite crucible at high temperature; a device to introduce the test portion and degas it under inert gas or in va
38、cuum at ambient temperature; a device for gas extraction in accordance with a predetermined temperature cycle; a purification train to remove water; a measuring device for the determination of the carbon monoxide or carbon dioxide.The materials needed will depend on the type of equipment used, for e
39、xample high purity inert gas (helium or argon).Calibration of the measuring device, when necessary, requires high purity gas, carbon monoxide, carbon dioxide, or certified metallic reference materials.5 Test portionThe analysis shall be carried out on one or several test portions. The number of test
40、 portions required to reach the required precision can be determined by a gauge repeatability and reproducibility study. If a gauge EN ISO 4491-4:2013 (E) DIN EN ISO 4491-4:2013-08 6 repeatability and reproducibility study is not made, the analysis shall be carried out on two test portions. Several
41、methods can be used to prepare the test portion prior to its introduction into the apparatus.a) The test portion is weighed directly into the degassed crucible.b) A quantity of the powder sample is uniaxially compacted in a small cylindrical die, without any lubricant or binder, under a pressure of
42、100 MN/mm2to 200 MN/mm2. The mass of the compact is determined.c) A quantity of the powder sample is enclosed in a small capsule of known weight made of platinum, tin, nickel, or iron-nickel foil of high purity. The whole capsule is weighed. The oxygen content of the foil shall be known or determine
43、d previously.d) In the case of a compact, a suitable fragment of the sample is weighed as the test portion.All weighings shall be to the nearest 0,1 mg.A metal foil capsule may be used solely to facilitate the introduction of the sample into the apparatus. In this case, the weight of the capsule sha
44、ll be kept to a minimum.Alternatively, the metal of the capsule can constitute the metal bath needed for convenient extraction; in this case, the mass of the capsule is chosen to give the bath/test-portion mass ratio recommended for the particular analysis.When the graphite crucible is used with a m
45、etal bath for several consecutive analyses, it is necessary to degas the bath prior to the beginning of each extraction operation.The bath/test-portion mass ratio is maintained larger than the recommended minimum value, if necessary, by the periodic introduction of fragments of metal followed by deg
46、assing of the bath.The mass of the test portion shall be selected depending on the sensitivity of the apparatus used and the expected oxygen content. Frequently, a mass between 0,1 g and 1 g is chosen.6 Procedure6.1 GeneralFor the reason given in the introduction, it is not possible to specify the c
47、onditions of oxygen determination for each of the various metals, alloys, and carbides to be analysed, and for each of the types of apparatus available. It should be noted that, especially when the reduction is carried out in the solid state and with continuous heating, the reaction may be slow and
48、the time for complete reduction of the oxides will depend on the oxygen content.It is recommended that the optional conditions for testing a given type of material and for a given range of oxygen contents be determined by performing preliminary tests. It is common to make successive tests on the same sample, increasing the reducing action (i.e. by increasing the temperature and/or time of reaction) until the measured oxygen content reaches a maximum constant value. Other parameters (e.g. use of metal bath) ma
