1、AECMA PRENZL32 A2 m LOL2311i 000220 2 A.E.C.M.A. STANDARD prEN2132 NORME A.E.C.M.A. Edition 1 January 1982 A. E.C.M.A. NORM ENGLISH VERSION ELECTRODEPOSITION OF CHROM1 UM FOR ENGINEERING PURPOSES AEROSPACE SERIES DEPOT ELECTROLYTIQUE DE CHROME LUFT- UND RAUMFAHRT POUR USAGES Ml%ANIQUES SERIE AEROSPA
2、TIALE GALVANISCHE METALLABSCHEIDUNG VON CHROM FR TECHNISCHE ZWECKE This industrial standard for the aerospace sector has been drawn up under the responsibility of AECMA (Association Europenne des Construteurs de Matriel Arospatial). It is published on yell0 w paper in three equivalent versions (Engl
3、ish, French, German). It will be submitted to CEN (European Committee for Standardizatibn) as a draft European Standard. Approved by The equivalent wrsionc in French end German languages -_ iDEEMALISATlC)N can be supplied by B.N.A.E., 8, rue Moreau-Vauthier of A.E.C.M.A. 1981-03-30 92100 BOULOGNE-BI
4、LLANCOURT - FRANCE. i - Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AECMA PREN2132 82 m 10123LB O002221 LI m lp. prEN2132 Page 2 CONTENTS 1 2 3 4 5
5、 6 7 8 9 10 11 SCOPE FIELD OF APPLICATION REFERENCES DEFINITIONS INFORMATION TO BE GIVEN TO THE PLATER THICKNESS OF PLATED COATING CONDITION OF SUBSTRATE PROCESSING SEQUENCE REMOVAL OF CHROMIUM PLATE RECLAMATION OF WORN OR UNDEX-PLATED PARTS INSPECTION AND TESTING ANNEX A ANNEX B ANNEX C ANNEX D ANN
6、EX E Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AECMA PREN2132 82 10L23LL O002222 b M prEN2132 Page 3 A.E.C.M.A. STANDARD . prEN2132 ELECTRODEPOSI
7、TION OF CHROMIUM FOR ENGINEERING PURPOSES SCOPE This standard specifies the chromium plating of parts made of carbon steels and alloy steels used in aerospace construction. It specifies : a) requirements for pretreatment, b) the method of electrodeposition of the chromium, c) maximum and minimum thi
8、cknesses, d) heat treatment, e) qualities required of the coating, f) methods of inspection. FIELD OF APPLICATION 2.1 Chromium coatings are applied in aerospace construction for one or more of the following purposes : a) resistance to wear, b) resistance to corrosion and wear, c) the building-up of
9、worn or over-machined parts. 2.2 Chromium plating should not normally be used on parts which be hotter than 450G in service. 2.3 When chromium plate is to be applied to steels of strength me Rm (max.) 1450 MPa which are subject to fatigue stresses in service, a treatment schedule together with inspe
10、ction procedure and test results establishing its validity shall be sent to the Official Service (Procurement Authority)., for approval. REFERENCES EN2409, DEFINITIONS Shot peening for inducement of compreCsive surface residual stresses 4.1 Symbols Rm (max.) : Maximum value of the tensile strength s
11、pecified in the standard for the steel to be treated, HV : Hardness VICKERS. 4.2 Units MPa : 1 MPa = 1 MN/m2 = 1 N/mm2. 1) in preparation Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking perm
12、itted without license from IHS-,-,- AECMA PREN2132 82 1OL231lt 0002223 B :- I. Cr. r. e prEN2132 Page 4 5 INFORMATION TO BE GIVEN TO THE PLATER The following information shall be given on the drawing or orders : a) The number of this standard, b) the standard and metallurgical condition of the subst
13、rate, c) the requirements for stress relieving and shot peening. If either or both of these treatments is not required, this shall be stated, d) the surfaces to be plated, e) the minimum thickness of chromium to be dep65ited and, where undercoats are applied, the total plating thickness. A maximum t
14、hickness may be quoted if desired, especially for the building-up of worn and over-machined parts. - These dimensions shall be those of the finished surface after any grinding of the plated parts, f) .the final surface texture of the chromium e.g., “as plated“ or ground to g) the requirements for he
15、at-treatment after plating. If no heat-treatment = h) the composition of the plating solution, if this is not the standard one a specified texture, is required, this shall be stated, described in Annex C.l, together with the required controls. 6 THICKNESS OF PLATED COATING 6.1 For resistance to wear
16、 only, iie. for parts that operate in a maintained environment of oil or grease The thickness required will depend on the conditions of service and shall be not less than 15 um. As a guide, 15 pm is Satisfactory against mild conditions of sliding rind 80 pm against moderately severe loading, but und
17、er heavy loading or when abrasives are present a minimum thickness of 250 pm may be needed. The thicknesses shall not normally exceed 300 pm. O 6.2 For resistance to wear and corrosion, $.e. for parts subject-to wear in an atmospheric environment The total thickness of coating shall be not less than
18、 50 um. The minimum thickness shall comply with clause 6.1. For more severe conditions of exposure the thickness shall be not less than 75 pm. The coating may if desired include an undercoat of nickel or bronze, or of copper with an intermediate coat of not less than 5 I.im nickel, but the thickness
19、 of the final coat of chromium shall be not less than 15 um* Nickel undercoats are preferred on steels of % (max.) 1450 MPa and resistance to severe conditions of corrosion. if necessary, on parts subjetc to fatigue, the applicability of the procedure shall be proved by prior testings. 6.3 For build
20、ing up worn or over-machined surfaces The minimum thicknesses shall comply with 6.1 and 6.2. Where a thickness of more than 250 um is needed to restore dimensions, a nickel undercoat may be applied and shall be machined before final chromium platingt On parts subject to heavy loading, a nickel under
21、coat should be of hard or electroless nickel. Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AECNA PREN2132 -2 = 1012311 0002224 T - _. R (;ax.) MPa U
22、p to and including 1100 Over i190 up to and including i450 Over 1450 up to and including 1800 Over i800 prEN2132 Page 5 7 CONDITION OF SUBSTRATE Stress relief None required 1 h at 19n bo 23OOC 18 h at i90 to 23OOC or for a shorter time at a higher temperature 24 h at 199 to 23OOC or for a shorter ti
23、me at a higher temperature 7.1 All. plastic forming and heat-treatment operations shall have been completed prior to chromium plating, Operations of metal removal from unplated areas may be done after plating. 7.2 The surface shall be free from metallurgical defects. 7.3 The surface texture shall be
24、 as smooth as possible and corners rounded. Parts on which the chromium coating is not to be ground after plating shall have an initial surface texture at least as smooth as that required for the chromium coating. Parts that are also to be cadmium plated shall be chromium plated first. 8 PROCESSING
25、SEQUENCE 8.1 Stress relief 8.1.1 Before being plated, parts shall be stress relieved. The conditions stated in table 1 shall be used, but different conditions may be used if they have been shown to be effective, TABLE i 8.1.2 If stress relief is given after shot peening, the temperature shall not ex
26、ceed 23OoC. 8.1.3 Surface hardened parts shall be stress relieved at 130 to 150C for not less than 5 h. Shorter times at a higher temperature may be used if the resulting loss of surface hardness of the substrate is acceptable Copyright Association Europeene des Constructeurs de Materiel Aerospatial
27、 Provided by IHS under license with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AECMA PREN2132 82 W LOLZ31L O002225 L W *- . - prEN2132 Page 6 8.2 Shot peening 8.2.1 8.2.2 8.2.3 Shot peening shall be applied to the requirements stated in table 2. TABLE 2 S
28、hot peening Up to and including 1100 Reconrraended if parts are subject to fatigue in service Over 1100 up to and including 14-50 Reconraended on all parts; escential if parts are subject ta fatigue in service Strongly recommended on all parts; are subject to fatigue in service (See clause 2.3) Over
29、 1450 essential if parts COTE : Parts uhich are to be heated at 400 to 4izg solution, it may be necessary to degrease them before returning them to the solution for etching and pIating. =-s- Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with
30、AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,- - _ AECMA PREN2132 82 101231L 0002227 5 Over 1800 i.L prEN2132 Page 8 400 to 48OOC for 1 h min. (Note 2) 190 to 23OOC for 18 h min. (Note 1) 8.4.6 After having been plated, parts shall be washed thoroughly, drie
31、d and freed from any masking material. The final wash water should preferably be demineralised and should preferably be hot, but the temperature shall not exceed a value 2OoC lower than the melting point of any masking material. An initial wash in midly alkaline water, pH 8 - 10, may be given if des
32、ired. 8.5 Post-plating heat treatment 8.5.1 Guidance on the reasons for heat treatment is given in Annex D. 8.5.2 Heat treatment shall be given as soon as possible and in any case within 4 h of plating. 8.5.3 Heat treatment shall be carried out in air according to table 4. TABLE 4 R, (mx.) MPa Up to
33、 and including 1100 Over li00 up to and including 1450 Over 1450 up to and including 1800 For reduction of hydrogen embrittlement, (a) of unpeened parts not subject to fatigue and (b) for all peened parts No heat treatment 190 to 23OOC for 2 h min. (Note 1) 190 to 23OOC for 6 h min. (Note 1) For red
34、uction of hydrogen embrittlernent and testoration of fatigue strength, unpeened parts only 400 to 480% for 1 h min. 400 to 480% for 1 h min. 400 to 48OC for i h min. (Note 2) MOTE 1 : Unpeened parts may be heated for a shorter time at a higher tenperature if the conditions have been shown to be effe
35、ctive in rechcing hydrogen embrittlenent. NOTE 2 : Seldom applicable, see Annex D. Surface hardened parts shall be heated at 130 to 15OOC for not less than 5 h,or at a higher temperature if the resulting loss of hardness of the substrate is acceptable. 9 REMOVAL OF CHROMIUM PLATE Chromium may be rem
36、oved either by grinding or by the electrochemical method described in Annex E. Undercoats af copper shall be removed, but sound, adherent, thick undercoats of nickel need not be removed. Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECM
37、ANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AECIA PREN2132 82 10L2311 0002228 i prEN2132 Page 9 I 10 RECLAMATION OF WORN OR UNDER-PLATED PARTS 10.1 Defective coatings and coatings that do not completely cover the substrate or undercoat, shall be completely rem
38、oved before plating. Complete removal is recommended also in all other cases. 10.2 Crack detection of worn parts before replating may be necessary. 11 10.3 Parts made of steel R, (max.) post-plating heat treatment, shall after the chromium plating has been removed, be heated at 190 to 23OOC for not
39、less than 1 hto ensure freedom from hydrogen before they are replated. (For surface hardened parts, see clause 8.5.3). 1100 MPa which were not given a 10.4 Parts shall then be pretreated and plated according to clauses 8.3 and 8.4 of this standard. Parts bearing an intact chromium coating may be rep
40、lated according to clauses 8.4.4 and 8.4.5. INSPECTION AND TESTIIUG 11.1 Appearance . The chromium plating shall be lustrous, smooth, fine grained and adherent and shall be free from pits, visible cracks, blisters, pores, exfoliation, burning and excessive build up at edges. Fine crazing, superficia
41、l staining from rinsing and slight discolouratior from heat treatment shall not he a cauce for rejection. Areas not required to be plated shall show no signs of corrosion or chemical attack and unless otherwise agreed, shall be free from chromium* 11.2 Thickness The thickness of chromium and any und
42、ercoats, on the finished parts shall be as specified on the drawing or order and shall comply with clause 6 of this standard. 11.3 Hardness The hardness of the coating shall be determined. The hardness of as plated chromium shall be not less than 750 HV. Coatings heat treated in the range of 400 to
43、48OOC shalL have a hardness of not less than 500 HV. The hardness shall be measured under a load appropriate to the thickness of the coating. 11.4 Adhesion The appearance of the chromium plating, before and after heat treatment and/or grinding shall be as described in clause 11.2. At the discretion
44、of the Inspection Authority destructive tests may be made e 11.5 Freedom from embrittlement The Procuring Authority or the Design Authority may require tests to be made to ensure freedom from hydrogen embrittlement. The tests may he Type Tests to establish the process and may be supplemented by peri
45、odic checks during production, Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AECMA PREN2132 A2 10123L1 0002229 9 ci- prEN2132 Page 10 ANNEX A METHOD
46、FOR DETERMINING THE INTENSITY OF SHOT-PEENING A. 1 The intensity of peening shall be measured according to EN2409 l). ANNEX B CLEANING B.l Before being plated, parts shall be cleaned to free the surface from foreign matter. The methods of cleaning chosen shall guarantee the continuity and adhesion o
47、f the chromium plate. They shall not affect dimensional tolerances or roughen the surface beyond the limit of design. They shall not alter the mechanical properties of the metal or cause hydrogen embrittlement. B.2 The following methods of cleaning are often used : B.2.1 Degreasing in solvents, in p
48、articular in chlorinated hydrocarbons, used cold or hot B.2.2 Immersion in mild alkaline cleaners with or without electric current. Cathodic current shall not be used on parts of strength R, (rnax. ) zw 1100 MPa. B.2.3 Mild abrasive blasting. B.2.4 Pickling in dilute mineral acid, preferably contain
49、ing inhibitor, with or without electric current. Cathodic picklingshal not be used on steels of strength Rm (rnax. ) 1100 MPa. Plain pickling without anodic current shall not be used on steels of strength R, (rnax.) 1450 Wa. B.2.5 Anodic pickling in sulphuric acid to an appropriate national standard. Suitable processes can be used on steels of strength Rm (max. ) 1450 MPa. 1) in preparation Copyrig
