1、April 2015 Translation by DIN-Sprachendienst.English price group 12No 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、77.060!%B3h“2311669www.din.deDDIN EN ISO 7441Corrosion of metals and alloys Determination of bimetallic corrosion in atmospheric exposurecorrosion tests (ISO 7441:2015);English version EN ISO 7441:2015,English translation of DIN EN ISO 7441:2015-04Korrosion von Metallen und Legierungen Bestimmung de
3、r Kontaktkorrosion durch Freibewitterungsversuche (ISO 7441:2015);Englische Fassung EN ISO 7441:2015,Englische bersetzung von DIN EN ISO 7441:2015-04Corrosion des mtaux et alliages Dtermination de la corrosion bimtallique par des essais dexposition de corrosionatmosphrique (ISO 7441:2015);Version an
4、glaise EN ISO 7441:2015,Traduction anglaise de DIN EN ISO 7441:2015-04SupersedesDIN EN ISO 7441:1995-04www.beuth.deDocument comprises 22 pagesIn case of doubt, the German-language original shall be considered authoritative.03.15DIN EN ISO 7441:2015-04 2 A comma is used as the decimal marker. Nationa
5、l foreword This standard (ISO 7441:2015) has been prepared by Technical Committee ISO/TC 156 “Corrosion of metals and alloys” (Secretariat: SAC, China) in collaboration with Technical Committee CEN/TC 262 “Metallic and other inorganic coatings”, (Secretariat: BSI, United Kingdom) in accordance with
6、the agreement on technical cooperation between ISO and CEN (Vienna Agreement). The responsible German body involved in its preparation was the DIN-Normenausschuss Materialprfung (DIN Standards Committee Materials Testing), Working Committee NA 062-01-77 AA Korrosions-prfverfahren. The DIN Standards
7、corresponding to the International Standards referred to in this document are as follows: ISO 1456 DIN EN ISO 1456 ISO 2081 DIN EN ISO 2081 ISO 6892-1 DIN EN ISO 6892-1 ISO 7599 DIN EN ISO 7599 ISO 8044 DIN EN ISO 8044 ISO 8407 DIN EN ISO 8407 ISO 8565 DIN EN ISO 8565 ISO 9223 DIN EN ISO 9223 Amendm
8、ents This standard differs from DIN EN ISO 7441:1995-04 as follows: a) Clause 4 “Overview and comparison of methods” has been supplemented; b) Clause 5 “Preparation of specimens”, 5.1 “Types of specimens” has been revised; c) Clause 7 “Evaluation of specimens” has been revised; d) the Annexes have b
9、een deleted; e) the standard has been editorially revised. Previous editions DIN EN ISO 7441: 1995-04 DIN EN ISO 7441:2015-04 3 National Annex NA (informative) Bibliography DIN EN ISO 1456, Metallic and other inorganic coatings Electrodeposited coatings of nickel, nickel plus chromium, copper plus n
10、ickel and of copper plus nickel plus chromium DIN EN ISO 2081, Metallic and other inorganic coatings Electroplated coatings of zinc with supplementary treatments on iron or steel DIN EN ISO 6892-1, Metallic materials Tensile testing Part 1: Method of test at room temperature DIN EN ISO 7599, Anodizi
11、ng of aluminium and its alloys General specifications for anodic oxidation coatings on aluminium DIN EN ISO 8044, Corrosion of metals and alloys Basic terms and definitions DIN EN ISO 8407, Corrosion of metals and alloys Removal of corrosion products from corrosion test specimens DIN EN ISO 8565, Me
12、tals and alloys Atmospheric corrosion testing General requirements DIN EN ISO 9223, Corrosion of metals and alloys Corrosivity of atmospheres Classification, determination and estimation DIN EN ISO 7441:2015-04 4 This page is intentionally blank EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN I
13、SO 7441 January 2015 ICS 77.060 Supersedes EN ISO 7441:1995English Version Corrosion of metals and alloys - Determination of bimetallic corrosion in atmospheric exposure corrosion tests(ISO 7441:2015) Corrosion des mtaux et alliages - Dtermination de la corrosion bimtallique par des essais dexpositi
14、on de corrosion atmosphrique (ISO 7441:2015) Korrosion von Metallen und Legierungen - Bestimmung der Kontaktkorrosion durch Freibewitterungsversuche(ISO 7441:2015) This European Standard was approved by CEN on 15 November 2014. CEN members are bound to comply with the CEN/CENELEC Internal Regulation
15、s 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 application to the CEN-CENELEC Management Centre or to any CEN member. Th
16、is 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 Management Centre has the same status as the official versions. CEN mem
17、bers 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, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portu
18、gal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2015 CEN All rights of exploitation in any fo
19、rm and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 7441:2015 EContents PageForeword .3Introduction .41 Scope . 52 Normative references 53 Terms and definitions . 54 Overview and comparison of methods 65 Preparation of specimens . 75.1 Types of specimens . 75.1.1 General
20、 75.1.2 Rectangular plates 75.1.3 Wire on bolt . 125.2 Number and marking of specimens . 136 Exposure of specimens 137 Evaluation of specimens 147.1 General 147.2 Evaluation based on mass loss . 147.3 Other evaluation methods applicable for rectangular plates 147.3.1 Evaluation based on visual exami
21、nation 147.3.2 Evaluation based on mechanical properties .157.4 Calculation of bimetallic effect . 158 Test report 16Bibliography .182EN ISO 7441:2015 (E) DIN EN ISO 7441:2015-04 Foreword This document (EN ISO 7441:2015) has been prepared by Technical Committee ISO/TC 156 “Corrosion of metals and al
22、loys” in collaboration with Technical Committee CEN/TC 262 “Metallic and other inorganic coatings” the secretariat of which is held by BSI. 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 July 201
23、5, and conflicting national standards shall be withdrawn at the latest by July 2015. 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. T
24、his document supersedes EN ISO 7441:1995. 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, Czech Republic, Denmark, Estonia, Finland, Former Y
25、ugoslav 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 Kingdom. Endorsement notice The text of ISO 7441:2015
26、has been approved by CEN as EN ISO 7441:2015 without any modification. 3EN ISO 7441:2015 (E) DIN EN ISO 7441:2015-04 IntroductionBimetallic corrosion occurs when a metal in electrical contact with a more noble metal corrodes at a higher rate than it would in the same environment but without this con
27、tact.Bimetallic corrosion in the atmosphere, in contrast to that in electrolytes, is characterized by a large potential drop between the anode and the cathode. Therefore, bimetallic corrosion is usually limited to a distance within about 0,5 cm from the point of contact1.The determination of bimetal
28、lic corrosion in atmospheric exposure tests can be made with several methods, each with its own advantages. Three standardized tests are compared and described in this International Standard: rectangular plates; washers; wire on bolt.The standard starts with an overview and comparison of the three m
29、ethods, with the purpose of aiding the selection of an appropriate test method. Test procedures for the rectangular plate and washer test are included in this standard since no independent standard describes these methods while those who wish to use the wire on bolt test need to consult ASTM G116 fo
30、r a complete description of the method.The standard describes how to derive the bimetallic effect, which is a relative measure of the bimetallic corrosion of a metal compared to the corrosion of the same metal but without the bimetallic effect. A high galvanic effect does not necessarily mean that t
31、he bimetallic corrosion rate is high. Therefore, valuable complementary information is the classification of the corrosivity of the test site according to ISO 92232.4EN ISO 7441:2015 (E) DIN EN ISO 7441:2015-04 1 ScopeThis International Standard specifies and compares methods for the determination o
32、f bimetallic corrosion of metals and coated metals in atmospheric exposure corrosion tests.NOTE In the text of this International Standard, the term “metal” is used for both metals and alloys, and the term “coated metal” for metals and alloys with metallic and non-metallic inorganic coatings.The met
33、hods are intended for the determination of the amount and type of corrosion effect, arising in natural atmospheres, caused by contact with different metals.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its ap
34、plication. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 1456, Metallic and other inorganic coatings Electrodeposited coatings of nickel, nickel plus chromium, copper plus nickel and
35、of copper plus nickel plus chromiumISO 2081, Metallic and other inorganic coatings Electroplated coatings of zinc with supplementary treatments on iron or steelISO 7599, Anodizing of aluminium and its alloys General specifications for anodic oxidation coatings on aluminiumISO 6892-1, Metallic materi
36、als Tensile testing Part 1: Method of test at room temperatureISO 8044, Corrosion of metals and alloys Basic terms and definitionsISO 8407, Corrosion of metals and alloys Removal of corrosion products from corrosion test specimensISO 8565, Metals and alloys Atmospheric corrosion testing General requ
37、irementsISO 15510, Stainless steels Chemical compositionASTM G116, Standard Practice for Conducting Wire-on-Bolt Test for Atmospheric Galvanic Corrosion3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 8044 and the following apply.3.1test specimensspeci
38、mens that are exposed for evaluation of bimetallic corrosion caused by contact with different materials5EN ISO 7441:2015 (E) DIN EN ISO 7441:2015-04 3.2reference specimensspecimens prepared, exposed and evaluated in the same configuration and design as the test specimens but not subject to bimetalli
39、c corrosion, for example by being in contact with an inert non-conductive material or the same material, instead of the different material3.3standard specimensspecimens used to determine the corrosivity of the test environment in absence of bimetallic corrosion3.4control specimensspecimens prepared
40、and evaluated in the same way as test specimens but, instead of being exposed in the test environment, stored under controlled conditions which prevent corrosion4 Overview and comparison of methodsThe determination of bimetallic corrosion in atmospheric exposure tests can be made with several method
41、s. Three of these methods are compared and described in this International Standard: rectangular plates; washers; wire on bolt.An overview and comparison of methods are shown in Table 1. Each configuration has its own advantages and the selection of method shall be based on the needs of the test pro
42、gramme. The main advantage with rectangular plate test is the possibility of evaluating the mechanical properties. The washer test is the only method where it is not necessary to know in advance which material is the anode. The short exposure time is the main advantage of the wire on bolt test.Table
43、 1 Comparison of rectangular plates, washers and wire on bolt for conducting test assessing bimetallic corrosion in the atmosphereEffect Rectangular plates Washers Wire on boltSensitivity (exposure time) 1 year 1 year 90 daysaMaterial limitation None None Wire anodeAnode/cathode Necessary to know in
44、 advance which material is the anodeNot necessary to know in advance which material is the anodeNecessary to know in advance which material is the anodeEvaluation method(s) Mass lossMechanical propertiesMass loss Mass lossMechanical Can be difficult to maintain electrical contact between pan-els thr
45、oughout the exposure test.Can be difficult to main-tain electrical contact between panels through-out the exposure test.Can be difficult to main-tain enough wire tension without causing wire fractureCrevice corrosion Crevice corrosion can be a problemCrevice corrosion can be a problemLower risk that
46、 crevice corrosion will be a prob-lemaA shorter duration of exposure is permissible under certain conditions, see Clause 6.6EN ISO 7441:2015 (E) DIN EN ISO 7441:2015-04 5 Preparation of specimens5.1 Types of specimens5.1.1 GeneralWhen determining the risk of bimetallic corrosion, depending on the pa
47、rticular test, the specimens will not only suffer from increased corrosion due to bimetallic effects. For example, in the wire on bolt test the wire tension may influence the outcome of the test depending on the particular application. Therefore, several types of specimens (test specimens, reference
48、 specimens, standard specimens and control specimens) as defined in Clause 3 are needed depending on the purpose of the test programme.NOTE Comparison of effects of test and reference specimens gives the relative risk of bimetallic corrosion but reference specimens are generally not suitable for eva
49、luation of the absolute corrosion attack when there is no risk of bimetallic corrosion due to the particular design of the specimens. For evaluation of the absolute attack standard specimens are more suitable. Flat or irregularly shaped specimens can be used, as described in ISO 8565, depending on the intended use of the tested material. For example, hanging wires can be used as standard specimens for the wire on bolt test but flat panels can also be used if they are easily obtained and mo
