1、BSI Standards PublicationBS EN 4707:2014Aerospace series Acidpickling of aluminum andaluminum alloy withouthexavalent chromiumBS EN 4707:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN 4707:2014.The UK participation in its preparation was entrusted to Techn
2、icalCommittee ACE/65/-/3, Paints, Surface Finish and ProtectiveTreatments for Aerospace Purposes.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsi
3、ble for its correctapplication. The British Standards Institution 2014. Published by BSI StandardsLimited 2014ISBN 978 0 580 84529 1ICS 25.220.20; 49.025.20Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theSt
4、andards Policy and Strategy Committee on 31 May 2014.Amendments issued since publicationDate Text affectedBS EN 4707:2014EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 4707 April 2014 ICS 25.220.20; 49.025.20 English Version Aerospace series - Acid pickling of aluminum and aluminum alloy witho
5、ut hexavalent chromium Srie arospatiale - Dcapage acid de lluminium et des alliages dluminium sans chrome hexavalent Luft- und Raumfahrt - Beizen von Aluminium und Aluminiumlegierungen ohne sechswertiges Chrom This European Standard was approved by CEN on 27 December 2013. CEN members are bound to c
6、omply 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 application to the CEN-CENE
7、LEC 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 Management Centre has the
8、 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, Lithuania, Luxembo
9、urg, 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 CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
10、 2014 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 4707:2014 EBS EN 4707:2014EN 4707:2014 (E) 2 Contents Page Foreword 3 1 Scope 4 2 Purpose of process .4 3 Normative references 4 4 Information for the processor 4 5 Condition of
11、 parts prior to processing 5 6 Process schedule 5 7 Pre-treatments 6 8 Treatment 6 9 Rinsing 7 10 Drying 7 11 Required characteristics and inspection 7 11.1 Parts 7 11.1.1 Inspection before treatment .7 11.1.2 Cleanliness .7 11.1.3 Inspection after treatment .7 11.2 Process .7 12 Quality assurance 8
12、 12.1 Approval of the processor 8 12.2 Process approval .8 12.3 Acceptance .8 13 Health, safety and environmental aspects 8 Annex A (normative) Pickling bath .9 BS EN 4707:2014EN 4707:2014 (E) 3 Foreword This document (EN 4707:2014) has been prepared by the Aerospace and Defence Industries Associati
13、on of Europe - Standardization (ASD-STAN). After enquiries 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 Services of the member countries of ASD, prior to its presentation to CEN. This Eur
14、opean Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by October 2014, and conflicting national standards shall be withdrawn at the latest by October 2014. Attention is drawn to the possibility that some of the el
15、ements 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. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this
16、European Standard: 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, Portugal, Romania, Slovakia,
17、 Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. BS EN 4707:2014EN 4707:2014 (E) 4 1 Scope This standard specifies the acid pickling of aluminium and aluminium alloys. It is applicable whenever referenced. 2 Purpose of process 2.1 Pre-treatment before penetrant testing/penetrant
18、 inspection. 2.2 Pre-treatment before anodizing. 2.3 Final treatment for parts prior to adhesive bonding application. 2.4 Final treatment before welding or brazing. 2.5 Pre-treatment before chemical milling. 2.6 Final treatment for parts prior to painting application. 2.7 Pre-treatment for parts pri
19、or to surface conversion coatings. 2.8 Desmutting (Blanchiment), after alkaline etching or acid pickling. 3 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition
20、 cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 9100, Quality Management Systems - Requirements for Aviation, Space and Defense Organizations 4 Information for the processor Designation; Number of the material standard and
21、metallurgical condition of the latter; Sequence of operations; Areas to be processed; Treatment. 5 Condition of parts prior to processing Fabrication of the parts shall have been completed before pickling. Toolings: Toolings, fixturings, and metal tooling masking must be protected from the corrosion
22、 and/or free from corrosion or another deterioration prejudicial to the treatment during their use. Design of the toolings and racking must be achieved in order to: avoid any retention of air or solution on the parts, BS EN 4707:2014EN 4707:2014 (E) 5 allow the neutralisation and the suppression of
23、the solutions during rinsing operations, avoid any accidental contact during treatment between parts and tank equipments, and between various parts. Tanks and rackings: Materials used must be resistant to temperature and chemically compatible with the products involved in the sequence of operations.
24、 6 Process schedule The pickling process shall be performed according to Table 1. Table 1 Post Pickling processes Process schedule Penetrant testing/ penetrant inspection Anodizing Adhesive bonding application Welding Or brazing Preparation before masking for chemical milling Painting application Su
25、rface conversion coatings Desmutting, after etching or pickling Pre-treatments Clause 7 Applicable Applicable Applicable Applicable Not applicable Applicable Applicable Applicable Pickling Clause 8 Applicable Applicable Applicable Applicable Applicable Applicable Applicable Applicable Post-treatment
26、s Rinsing Applicable Applicable Applicable Applicable Applicable Applicable Applicable Applicable Drying Applicable Not applicable Applicable Applicable Applicable Applicable Not applicable Not applicable Post pickling maximum lead-time 16 h aImmediately in process 8 h 8 h a 8 h aor Immediately in p
27、rocess 16 h aImmediately in process Immediately in process aRecommended (in case of over lead time an appropriate storage and visual inspection (according 11.1) should be carried out before and after the post pickling process). 7 Pre-treatments Heavily soiled/Polluted parts shall be emulsion cleaned
28、, vapour degreased or solvent cleaned. If there is a significant natural oxide film (ex.: laminated parts or oxidized parts), carry out abrasive blasting or chemical deoxidizing. Sequence of operations 1) Pre-degreasing: alkaline degreasing (with rinsings); or solvent; or vapour solvent. BS EN 4707:
29、2014EN 4707:2014 (E) 6 NOTE If necessary (laminated parts / oxidized parts), do a chemical deoxidizing (with rinsings) or abrasive blasting after pre-degreasing. 2) A second alkaline degreasing shall be performed after pre-degreasing, if necessary. The alkaline degreasing shall be: corrosion inhibit
30、ed; preferably of a non-silicated type (especially for dye penetrant inspection). Generally alkaline solutions with pH between 9 and 11 are considered as a degreasing-etching solutions, whereas those with pH between 7 and 9, are considered only as a degreasing solution. For the parts to be bonded, a
31、 non-silicated alkaline solution is mandatory. 3) After alkaline degreasing/cleaning, the parts shall be thoroughly water rinsed and inspected for water break. Cleaning shall be repeated if break occurs. 8 Treatment Immediately after pre-treatments, the parts shall be pickled in one of the solutions
32、 specified below. To ensure a well pickled surface, excessive bath loading and shielding of parts by each other shall be avoided: Type of substances that can be used in pickling: Nitric or sulfonitric; Phosphosulfonitric; Sulfonitro-ferric fluoride free; Sulfonitro-ferric with fluoride. 9 Rinsing Af
33、ter each treatment bath, water rinsing is mandatory. This operation has to be composed by at least one recycled rinsing. Recycled rinsing is generally completed by non-recycled or low-flow rate rinsing. Several quality of rinsing water can be used but the water used before surface treatment (see Tab
34、le 1) rinsing shall have a conductivity not more than 70 S/cm. Rinsing shall be carried out consecutively to the pickling step in running water with a temperature not exceeding 40 C. 10 Drying The parts shall be dried except for those submitted for subsequent chemical treatment, anodic treatment or
35、desmutting/chemical conversion The temperature shall not exceed 80 C. After drying, parts shall be protected against contamination. In case of bonding and paint applications, parts shall be stored under clean, dry conditions. BS EN 4707:2014EN 4707:2014 (E) 7 11 Required characteristics and inspecti
36、on 11.1 Parts 11.1.1 Inspection before treatment By visual inspection, make sure that the parts to be protected/treated are free from defects such as: scratches, corrosion pits, cracks prejudicial to the aspect or the effectiveness of protection. Adherent chips and metal particles must be removed be
37、forehand using a clean cloth. 11.1.2 Cleanliness During the degreasing phases, each rinsing operation must be followed by a water break test in order to evaluate the wettability (and the cleanliness) of the surfaces. This test consists of covering the parts with a uniform water film. This water film
38、 must cover the parts for at least 30 s without any discontinuity in the film. Otherwise, degreasing phases have to be repeated. 11.1.3 Inspection after treatment When subjected to visual inspection, the pickled surfaces shall be of a homogeneous appearance and free from pitting, stains and contamin
39、ation. 11.2 Process 11.2.1 Air used for drying or other operations shall be substantially dry and free from oil. 11.2.2 Chemical analysis of the pickling solutions (and different baths involved in the sequence of operations) shall be carried out at regular intervals to determine the content of heavy
40、 metal, chloride, iron copper etc., when requested. 11.2.3 The bath shall be discarded when pitting of parts occurs or when solid material starts to precipitate on cooling the solution to ambient temperature. The process must be managed by monitoring the significant parameters as aluminium and pollu
41、ant contents. 11.2.4 The purity of the rinsing water shall be determined by conductivity/resistivity measurements. 11.2.5 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. 11.2.6 Each pickling pro
42、cess must be characterized by its specific etching rate range. All pickling process must not lead to localized attack. 11.2.7 The etching rate of the complete sequence of operations must be periodically measured to ensure the control of the process. NOTE The etching rate and maximum dipping time can
43、not be generally specified but has to be specified according to final customer requirements. 12 Quality assurance 12.1 Approval of the processor See EN 9100. BS EN 4707:2014EN 4707:2014 (E) 8 12.2 Process approval The processor shall carry out: pickling on a series of test pieces or pre-production p
44、arts agreed between the purchaser and processor; tests specified in this standard, unless otherwise agreed between the purchaser and processor (e.g.: dissolution rate, morphology, roughness, ). When the test results have been accepted/considered as satisfactory by the purchaser, he shall give his wr
45、itten approval to start production. The procedure shall not be changed without previous agreement from the purchaser. 12.3 Acceptance After pickling the parts shall have the required characteristics according to Clause 12. The frequency and nature of the inspection shall be specified in the design d
46、ocuments or agreed between processor and purchaser. Parts that do not meet the requirements shall be rejected. Parts which develop water break shall be reprocessed. 13 Health, safety and environmental aspects The locally applicable regulations and laws shall be observed. BS EN 4707:2014EN 4707:2014
47、(E) 9 Annex A (normative) Pickling bath Table A.1 Post pickling application Pickling bath Penetrant testing/ Penetrant inspection Anodizing Adhesive bonding application Chemical milling Welding or brazing Painting/ Organic film application Surface conversion coatings Desmutting, after etching or pic
48、kling Nitric Or sulfonitric Applicable Applicable Applicable Applicable Applicable Applicable Applicable Applicable Phospho-sulfonic Not applicable Applicable Not applicable Not applicable Not applicable Applicable Applicable Not applicable Sulfonitro-ferric Without fluoride Applicable Applicable Ap
49、plicable Applicable Applicable Applicable Not applicable Applicable Sulfonitro-ferric With fluoride Applicable Applicable Not applicable Applicable Applicable Applicable Not applicable Applicable This page deliberately left blankThis page deliberately left blankBSI is the national body responsible for preparing British Standards and other standards-related publications, information and services.BSI is incorporated by Royal Charter. British Standards and other standardization products are published by BSI Standards Limited.Brit
