《BS-EN-2334-1997.pdf》由会员分享,可在线阅读,更多相关《BS-EN-2334-1997.pdf(12页珍藏版)》请在三一文库上搜索。
1、BRITISH STANDARD AEROSPACE SERIES BS EN 2334:1997 Chromic-sulphuric acid pickle of aluminium and aluminium alloys The European Standard EN 2334:1997 has the status of a British Standard ICS 49.040 Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 02 18:00:38 GMT+00:00 2006, Uncontrolled Copy, (c)
2、BSI BS EN 2334:1997 This British Standard, having been prepared under the direction of the Engineering Sector Board, was published under the authority of the Standards Board and comes into effect on 15 November 1997 BSI 04-2000 ISBN 0 580 28135 3 National foreword This British Standard is the Englis
3、h language version of EN 2334:1997. The UK participation in its preparation was entrusted to Technical Committee ACE/44, Protective treatments and aircraft finishes, which has the responsibility to: aid enquirers to understand the text; present to the responsible European committee any enquiries on
4、the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Stan
5、dards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. NOTEUnder the AE
6、CMA part numbering system, normative references to the Parts of AECMA-originated European Standards may appear in clause 2 in the form of a three-digit number e.g 001 where the BSI and CEN systems would use the form 1. It can be assumed that, wherever referenced, the three-digit and single digit for
7、ms can be used interchangeably. For the purposes of part-marking of components produced in accordance with this standard, the three-digit form should be used. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for the
8、ir correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the EN title page, pages 2 to 6 and a back cover. This standard has been updated (see c
9、opyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 02 18:00:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN
10、2334:1997 BSI 04-2000i Contents Page National forewordInside front cover Foreword2 Text of EN 23343 Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 02 18:00:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 02 18:00:38 GMT+00:00 2006, Unco
11、ntrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 2334 July 1997 ICS 49.040.40 Descriptors: Aircraft industry, aluminium, aluminium alloys, cleaning English version Aerospace series Chromic-sulphuric acid pickle of aluminium and aluminium alloys Srie arospatiale Dcapage sul
12、fochromique de laluminium et des alliages daluminium Luft- und Raumfahrt Beizen von Aluminium und Aluminiumlegierungen in Chromschwefelsure This European Standard was approved by CEN on 1996-08-04. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditio
13、ns 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 Central Secretariat or to any CEN member. The European Standards exist in three offi
14、cial 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 Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria,
15、Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secr
16、etariat: rue de Stassart 36, B-1050 Brussels 1997 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 2334:1997 E Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 02 18:00:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 2334:1997 B
17、SI 04-2000 2 Foreword This European Standard has been prepared by the European Association of Aerospace Manufacturers (AECMA). After inquiries and votes carried out in accordance with the rules of this Association, this Standard has received the approval of the National Associations and the Official
18、 Services of the member countries of AECMA, prior to its presentation to CEN. 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 January 1998, and conflicting national standards shall be withdrawn at
19、 the latest by January 1998. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembo
20、urg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Contents Page Foreword2 1Scope3 2Normative references3 3Purpose of process3 4Information for the processor3 5Condition of parts prior to processing3 6Process schedule3 7Pre-treatments4 8Treatment4 9Post-treatments
21、4 10Required characteristics and inspection4 11Quality assurance5 12Health, safety and environmental aspects5 13Designation5 Annex A (normative)6 Table 13 Table A.1 Pickling solutions6 Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 02 18:00:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 2334:
22、1997 BSI 04-20003 1 Scope This standard specifies the acid chromate pickling of aluminium and aluminium alloys except those with a silicon content in excess of 2 % or a copper content in excess of 5 %. It is applicable whenever referenced. 2 Normative references This European Standard incorporates b
23、y dated or undated reference provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Stand
24、ard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN 2000, Aerospace series Quality assurance EN aerospace products Approval of the quality system of manufacturers. 3 Purpose of process 3.1 Reference surface t
25、reatment, e.g. prior to adhesive bonding or primer application to test specimens used for qualification and acceptance tests on adhesives, paints, sealants (treatment A) 3.2 Final treatment for parts prior to adhesive bonding or primer application (treatment B) 3.3 Pre-treatment prior to anodizing f
26、or adhesive bonding (treatment C) 3.4 Pre-treatment (treatment D) for: anodizing for other applications than adhesive bonding; other chemical treatments. 4 Information for the processor Designation, see 13 Number of the material standard and metallurgical condition of the latter Sequence of operatio
27、ns Areas to be processed Treatment 5 Condition of parts prior to processing Fabrication of the parts shall have been completed before pickling. 6 Process schedule The pickling process shall be performed according to Table 1. Table 1 Process schedule Application, see treatment ABCD Pre-treatments7.17
28、.27.27.2 Pickling8888 Post-treatments 9.19.19.19.1 9.29.2 9.39.3 Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 02 18:00:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 2334:1997 4 BSI 04-2000 7 Pre-treatments 7.1 Cleaning for treatment A (see 3.1) 7.1.1 Vapour degreasing, solvent cleaning or
29、alkaline cleaning with a non-etching, non-silicated hot alkaline solution. 7.1.2 Water rinsing and check for water break, repeat cleaning if break occurs. 7.2 Cleaning for treatments B, C, D (see 3.2, 3.3 and 3.4) 7.2.1 Heavily soiled parts shall be emulsion cleaned, vapour degreased or solvent clea
30、ned. 7.2.2 If there is a natural oxide film, carry out abrasive blasting or chemical deoxidizing. When pickling does not follow immediately after these operations, the parts shall be vapour degreased or cleaned with a hot alkaline solution. 7.2.3 If there is no significant natural oxide film, parts
31、shall be cleaned with a hot alkaline solution. The alkaline solution shall be corrosion inhibited and preferably of a non-silicated type. For the parts to be bonded a non-silicated alkaline solution is mandatory. After alkaline cleaning, the parts shall be thoroughly water rinsed and inspected for w
32、ater break. Cleaning shall be repeated if break occurs. 8 Treatment Immediately after final cleaning, the parts shall be pickled in one of the solutions specified in Annex A. To ensure a well pickled surface, the following shall be observed: excessive bath loading and shielding of parts by each othe
33、r shall be avoided; to ensure satisfactory adhesion and durability properties for treatments A and B or to obtain a satisfactory metal removal rate, pure aluminium and certain aluminium alloys with a very low copper content at the surface (clad aluminium alloys, Al-Mg alloys) require additional prov
34、isions. The parts in these materials shall be either suspended on supporting jigs which shall be more noble (cathodic) relative to the materials to be treated, e.g. unclad Al-Cu alloy, or coupled to auxiliary cathodes. The position of the parts (anodes) relative to the cathodic areas and the cathodi
35、c to anodic area ratio shall be chosen carefully. Electrical contacts at several points shall be provided. 9 Post-treatments 9.1 Rinsing It shall be carried out as quickly as possible after pickling in running water with a temperature not exceeding 40 C. The water used for final rinsing shall have a
36、 conductivity not more than 70 4S/cm. 9.2 Drying The parts shall be dried except for those submitted for subsequent chemical or anodic treatment. The temperature shall be k 65 C. The dry parts shall be protected against contamination. 9.3 Treatment after drying As the adhesives and primers shall be
37、applied within 16 h of drying for treatment B and within 4 h for treatment A, necessary measures shall be taken. Moreover, it shall be ensured that the treated parts are stored under clean, dry conditions. 10 Required characteristics and inspection 10.1 Parts 10.1.1 Cleanliness No water break shall
38、be observed when the surface is wetted with clean water (max. temperature 35 C) by immersion or spray. This operation has to be carried out after final rinsing. 10.1.2 Appearance When subjected to visual inspection, the pickled surfaces shall be of a homogeneous appearance and free from pitting, sta
39、ins and contamination. Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 02 18:00:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 2334:1997 BSI 04-20005 10.2 Process 10.2.1 Air used for drying or other operations shall be dry and free from oil. 10.2.2 Mercury or mercury compounds shall not be pre
40、sent in any of the materials used. 10.2.3 Chemical analyses of the pickling solutions shall be carried out at regular intervals to determine the content of Cr6+, free acid, chloride, iron, copper, aluminium and, when requested, the Cr3+ content to ensure that the composition is maintained within the
41、 limits specified in Annex A. 10.2.4 The purity of the rinsing water shall be determined by conductivity measurements. 10.2.5 When required for adhesive bonding, the test to the relevant bonding standard shall be carried out to ensure that the process has been correctly applied. 11 Quality assurance
42、 11.1 Approval of the processor See EN 2000. 11.2 Process approval The processor shall carry out: pickling on a series of test pieces or pre-production parts agreed between the purchaser and processor; the tests specified in this standard, unless otherwise agreed between the purchaser and processor.
43、 When the test results have been accepted as satisfactory by the purchaser, he shall give his written approval to start production. The procedure shall not be changed without previous agreement from the purchaser. 11.3 Acceptance After pickling, the parts shall have the required characteristics acco
44、rding to 10. The frequency and nature of the inspection shall be specified in the design documents or agreed between processor and purchaser. Parts not meeting the requirements shall be rejected. Parts which develop water break shall be reprocessed. 12 Health, safety and environmental aspects The lo
45、cally applicable regulations and laws shall be observed. 13 Designation EXAMPLE: Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 02 18:00:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 2334:1997 6 BSI 04-2000 Annex A (normative) Table A.1 Pickling solutions The solutions shall be discarded whe
46、n pitting of parts occurs or when solid material starts to precipitate on cooling the solution to ambient temperature. The latter depends on the combined effect of dissolved metal and free acid content and can be expected at an aluminium content above 14 g/l. Pickling solutions Application to treatm
47、ent A and BC and D Chromic acid (CrO3)45 g/l to 55 g/l30 g/l to 55 g/l Free sulphuric acid (H2SO4)220 g/l to 300 g/l a 150 g/l to 300 g/l a Water b RemainderRemainder Chloride (as NaCl)0,2 g/l max.0,2 g/l max. Aluminium c 1,5 g/l min. Copper c 0,06 g/l to 1 g/l1 g/l max. Iron1 g/l max.1 g/l max. Tem
48、perature60 C to 65 C d 60 C to 65 C d Immersion time28 min to 30 min e 20 min to 30 min e Sodium dichromate (Na2Cr2O7. 2H2O)67 g/l to 83 g/l45 g/l to 83 g/l Free sulphuric (H2SO4)220 g/l to 300 g/l f 150 g/l to 300 g/l f Water b RemainderRemainder Chloride (as NaCl)0,2 g/l max.0,2 g/l max. Aluminium
49、 c 1,5 g/l min. Copper c 0,06 g/l to 1 g/l1 g/l max. Iron1 g/l max.1 g/l max. Temperature60 C to 65 C d 60 C to 65 C d Immersion time28 min to 30 min e 20 min to 30 min e a H 2SO4: (4,5 to 5,5 CrO3) b The solutions shall be prepared and maintained at the operating level with water having a conductivity k 100 4S/cm and checked at regular intervals to ensure conformance with the tolerances specified for the composition. c To reach the required minimum aluminium and copper content, a fresh solution shall be
链接地址:https://www.31doc.com/p-3740647.html