1、July 2009DEUTSCHE NORM English price group 10No part of this standard 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 77.150.30!$Xj?“1537128www
2、.din.deDDIN EN 723Copper and copper alloys Combustion method for determination of the carbon content on theinner surface of copper tubes or fittingsEnglish version of DIN EN 723:2009-07Kupfer und Kupferlegierungen Verfahren zur Bestimmung des Kohlenstoffgehaltes auf der Innenoberflche vonKupferrohre
3、n oder Fittings durch VerbrennenEnglische Fassung DIN EN 723:2009-07SupersedesDIN EN 723:1996-10www.beuth.deDocument comprises pages14DIN EN 723:2009-07 National foreword This standard has been prepared by Technical Committee CEN/TC 133 “Copper and copper alloys” (Secretariat: DIN, Germany). The res
4、ponsible German body involved in its preparation was the Normenausschuss Nichteisenmetalle (Nonferrous Metals Standards Committee), Technical Committee NA 066-02-03 AA Kupferrohre (Installation und Industrie). Amendments This standard differs from DIN EN 723:1996-10 as follows: a) The accuracy of th
5、e method has been improved. b) The scope of the standard has been extended to include fittings of copper alloys. c) The standard has been simplified by specifying only one method for carbon content determination, namely that of infrared absorption spectrometry; (The method using tetrabutylammonium h
6、ydroxide (HTBA) and the method of determination by measurement of differential electrical conductivity (coulometric) have been deleted). d) The standard has been simplified by specifying only one cutting method for tubes with diameters exceeding the furnace diameter by deletion of the “longitudinal
7、cutting method”. e) Clause 2 “Normative References” has been changed to “Bibliography”, and the document renumbered. Previous editions DIN EN 723: 1996-10 2 EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 723April 2009ICS 77.150.30 Supersedes EN 723:1996 English VersionCopper and copper alloys - C
8、ombustion method fordetermination of the carbon content on the inner surface ofcopper tubes or fittingsCuivre et alliages de cuivre - Mthode de dtermination parcombustion de la teneur en carbone la surface internedes tubes ou des raccords en cuivreKupfer und Kupferlegierungen - Verfahren zur Bestimm
9、ungdes Kohlenstoffgehaltes auf der Innenoberflche von Kupferrohren oder Fittings durch VerbrennenThis European Standard was approved by CEN on 19 March 2009.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the s
10、tatus of a national standard without any alteration. Up-to-date lists and bibliographical references concerning 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).
11、A version in any other language made by translationunder the responsibility of a CEN member into its own language 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,
12、 Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALIS
13、ATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: Avenue Marnix 17, B-1000 Brussels 2009 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 723:2009: EEN 723:2009 (E) 2 Contents Page Foreword 3 1 Scope 4 2 Terms and definitions .4 3
14、 Principle 4 4 Preparation of samples and test pieces 4 4.1 Preparatory procedures 4 4.1.1 General 4 4.1.2 Residual carbon content .5 4.1.3 Total carbon content .5 4.1.4 Potential carbon content .5 4.2 Preparation of samples .5 4.2.1 Tubes 5 4.2.2 Fittings 5 4.3 Cleaning of sample surfaces 5 4.3.1 C
15、leaning of inner surface of sample 5 4.3.2 Cleaning of outer surface of sample6 4.4 Preparation of test pieces .7 4.4.1 Tubes 7 4.4.2 Fittings 8 5 Method for carbon content determination 9 5.1 General 9 5.2 Determination of the carbon content 10 5.3 Determination of the blank value 10 6 Expression o
16、f results . 10 7 Calibration . 11 8 Test report . 11 Bibliography . 12 DIN EN 723:2009-07 EN 723:2009 (E) 3 Foreword This document (EN 723:2009) has been prepared by Technical Committee CEN/TC 133 “Copper and copper alloys”, the secretariat of which is held by DIN. This European Standard shall be gi
17、ven the status of a national standard, either by publication of an identical text or by endorsement, at the latest by October 2009, and conflicting national standards shall be withdrawn at the latest by October 2009. Attention is drawn to the possibility that some of the elements of this document ma
18、y 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 723:1996. In comparison with the first edition of EN 723:1996, the following significant technical changes and one significant editorial chan
19、ge were made: improvement of the accuracy of the method; extension of the scope of the standard to fittings of copper alloys; simplification by limitation to only one method for carbon content determination, namely that of infrared absorption spectrometry: Method using tetrabutylammonium hydroxide (
20、HTBA) and Method of determination by measurement of differential electrical conductivity (coulometric) deleted; simplification by limitation to only one cutting method for tubes with diameters exceeding the furnace diameter by deletion of the “longitudinal cutting method“; change of Clause 2 “Normat
21、ive References“ into “Bibliography“ with renumbering. 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, Franc
22、e, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. DIN EN 723:2009-07 EN 723:2009 (E) 4 1 Scope This European Standard specifies a combustio
23、n method for determining the carbon content, if any, on the inner surface of tubes of copper or fittings of copper or copper alloys. This standard applies only to seamless, round copper tubes as specified for example in EN 1057 and EN 13348 or fittings of copper or copper alloys as specified in EN 1
24、254 (all parts). 2 Terms and definitions For the purposes of this document, the following terms and definitions apply: 2.1 residual carbon CRcarbon present in the chemical form of elemental carbon 2.2 potential carbon CPcarbon present in the chemical form of organic compounds EXAMPLE Organic compoun
25、ds: oils, greases, etc. 2.3 total carbon CTsum of residual carbon and potential carbon 3 Principle Combustion of the carbon present on the inner surface of a tube or fitting sample, carried out at a given temperature in an oxygen flow. Determination, by infrared absorption spectrometry, of the resid
26、ual or total carbon content, or both, by measurement of the carbon dioxide generated. Calculation of potential carbon content is by subtraction of the residual carbon content from the total carbon content. 4 Preparation of samples and test pieces 4.1 Preparatory procedures 4.1.1 General Carry out th
27、e procedures in 4.1.2, 4.1.3 or 4.1.4 depending on the carbon to be determined and taking account of the following precautions: a) metal cutting tool shall be free from protective paint; b) clamps shall be flat and consist of copper, aluminium, steel or an alternative material. Alternative materials
28、 shall not be detrimental to their cleanliness; DIN EN 723:2009-07 EN 723:2009 (E) 5 c) all tools and implements used for cutting or clamping samples shall be degreased before sample preparation; d) degreasing shall be done by wiping with a lint-free cloth containing absorbed tetrachloroethylene, tr
29、ichloroethylene or trichloroethane or, because of potential for environmental harm, other solvents of equivalent performance, e.g. acetone. These solvents shall also be used for cleaning/immersion of samples where appropriate; e) suitable protective gloves should be used to ensure skin contact with
30、the surface under test is avoided; f) between the cleaning operation and the combustion operation, the test pieces shall be kept in a non-contaminating environment, such as a clean laboratory or in a desiccator containing sodium hydroxide pellets. The tests shall be completed within approximately 5
31、h of cleaning the sample, or if not, the sample shall be re-cleaned. 4.1.2 Residual carbon content a) prepare samples (see 4.2); b) clean inner and outer surface of sample (see 4.3.1 and 4.3.2); c) prepare test pieces (see 4.4). 4.1.3 Total carbon content a) prepare samples (see 4.2); b) clean outer
32、 surface of sample (see 4.3.2); c) prepare test pieces (see 4.4). 4.1.4 Potential carbon content Prepare separate samples and test pieces following the procedures in 4.1.2 and 4.1.3. 4.2 Preparation of samples 4.2.1 Tubes Cut a sample approximately 30 cm long from a tube, using a metal-cutting saw o
33、r a pipe cutter. Deburr the outer and inner edges of the sample ends, using a smooth file or a trimming blade, take care that any burrs removed do not fall into the bore of the tube. 4.2.2 Fittings Select sufficient fittings from the batch in order to be able to cut test pieces from them having a mi
34、nimum total internal surface area of 10 cm2. 4.3 Cleaning of sample surfaces 4.3.1 Cleaning of inner surface of sample The following steps shall be performed in a fume cupboard. Immerse the sample, for a minimum of 2 min in an agitated bath of boiling chlorinated solvent, for example, analytical gra
35、de trichloroethylene or trichloroethane, that shall be used as reference in case of dispute ensuring that the solvent baths are kept topped up, such that the sample remains totally immersed in the solvent. Immerse the sample in a second, boiling solvent bath for at least 30 s. DIN EN 723:2009-07 EN
36、723:2009 (E) 6 Remove the sample from the bath and place it vertically under a fume hood or on a grease-free plate in an oven operating at a temperature of at least 80 C for a minimum of 60 s, until the solvent has totally evaporated. Refresh both baths periodically, as appropriate, in accordance wi
37、th written internal procedures. 4.3.2 Cleaning of outer surface of sample 4.3.2.1 General Degrease the outside surface of the sample by wiping with a clean, lint-free, solvent-containing cotton cloth, taking care to ensure that no fibres remain on the sample after wiping. Clean the sample by chemica
38、l cleaning method, see 4.3.2.2, or for tubes in R250 and R290 material conditions1)only, the alternative mechanical cleaning method, see 4.3.2.3, except in cases of dispute or preparation for blank value determination, may be used. 4.3.2.2 Chemical cleaning 4.3.2.2.1 Sealing a) For annealed tubes on
39、ly: Squashing/flattening a 20 mm (approx.) portion of the tube extending from one end, between clamps (see 4.1) placed between the jaws of a vice. The squashed end is then folded over and also squashed/flattened against the adjacent, 20 mm (approx.) length of tube, again using clamps (see 4.1) fixed
40、 between the jaws of a vice. This method shall be used for reference testing. b) For tubes or fittings: Seal one tube end or all fitting ends by inserting appropriately-sized, silicone or neoprene plugs. NOTE If necessary, the ends of tubes in annealed material condition should firstly be re-rounded
41、 using an appropriate, degreased re-rounding tool, in order to obtain a leak-tight seal with the plug. 4.3.2.2.2 Cleaning Place the degreased sample in a clean beaker containing fresh diluted nitric acid for half starting from 50 % concentrated nitric acid. The temperature of the acid shall be at le
42、ast 20 C and for handling reasons, care has to be taken to control the exothermic reaction, if necessary by cooling the beaker. a) For tubes: The beaker shall contain sufficient solution to cover between 75 mm and 125 mm of the length of the sample (the smaller the diameter of the tube being tested,
43、 the greater the depth of immersion required to ensure a sufficiently covered surface area). b) For fittings: The beaker shall contain a sufficient quantity of solution to cover the sample. Refresh the acid bath weekly or after preparation of about forty samples (whichever is the sooner). 1) see EN
44、1173 for the explanation of R250 and R290. DIN EN 723:2009-07 EN 723:2009 (E) 7 Ensure that the sample remains in the acid solution for at least 30 s so that copious quantities of brown fumes (NO2) are expelled. This step of operation shall be performed in a fume cupboard. Withdraw the sample from t
45、he acid solution and rinse thoroughly with deionised water. Transfer the sample to a bath containing boiling deionised water for a duration between 30 s and 60 s, which, before use shall have been boiled for approx. 5 min to ensure a complete degassing of the water, or rinse the sample with hot (min
46、. 50 C) running water for at least 30 s. Take care to ensure that the useful part of the sample is fully immersed in the water bath. Due to an uptake of CO2from the air, refresh the deionised water every day or after the preparation of about forty samples (whichever is sooner). Remove the sample fro
47、m the bath and place it vertically under a fume hood or on a grease-free plate in an oven operating at a temperature of at least 80 C for a minimum of 60 s, until the water has totally evaporated or let it dry on air. 4.3.2.3 Mechanical cleaning Hold the tube in a vice and remove all traces of the o
48、uter surface in the area to be tested, using a degreased file. Alternatively, a thin layer from the outer surface may be removed by turning on a lathe using a tool with a degreased tip. All tools used for mechanical cleaning shall be free of organic contamination. The tools shall not be used for oth
49、er mechanical operation. 4.4 Preparation of test pieces 4.4.1 Tubes 4.4.1.1 General Carry out the procedure given in 4.4.1.2 or 4.4.1.3, depending on the tube diameter, and taking account of the precautions described in 4.1. 4.4.1.2 Tubes with diameters not exceeding the furnace diameter From the cleaned sample, cut and discard a 2,5 cm length, from one end which, in the case of a chemically cleaned outer surface, shall be from the plugged or flattened end of the tube (having firstly removed the plug from the tube end if appropriate). Measure the required
