1、ASD-STAN STANDARD NORME ASD-STAN ASD-STAN NORM prEN 4826 Edition P 1 March 2013 PUBLISHED BY THE AEROSPACE AND DEFENCE INDUSTRIES ASSOCIATION OF EUROPE - STANDARDIZATIONRue Montoyer 10 - 1000 Brussels - Tel. 32 2 775 8126 - Fax. 32 2 775 8131 - www.asd-stan.orgICS: Descriptors: ENGLISH VERSION Aeros
2、pace series Zinc-Nickel (12-16 % Ni) plating of steels with specified tensile strength 1 450 MPa, copper alloys, nickel alloys and aluminium alloys for parts and fasteners Srie arospatiale Dpt lectrolytique Zinc-Nickel (12-16 % Ni) sur aciers de rsistance 1 450 MPa, sur alliages de cuivre, alliages
3、de nickel et alliages daluminium pour pices et lments de fixation Luft- und Raumfahrt Zink-Nickel (12-16 % Ni) Stahlbeschichtung mit festgelegter Zugfestigkeit 1 450 MPa, Kupfer-, Nickel- und Aluminiumlegierungen fr Verbindungsteile und Verschlsse This “Aerospace Series“ Prestandard has been drawn u
4、p under the responsibility of ASD-STAN (The AeroSpace and Defence Industries Association of Europe - Standardization). It is published for the needs of the European Aerospace Industry. It has been technically approved by the experts of the concerned Domain following member comments. Subsequent to th
5、e publication of this Prestandard, the technical content shall not be changed to an extent that interchangeability is affected, physically or functionally, without re-identification of the standard. After examination and review by users and formal agreement of ASD-STAN, it will be submitted as a dra
6、ft European Standard (prEN) to CEN (European Committee for Standardization) for formal vote and transformation to full European Standard (EN). The CEN national members have then to implement the EN at national level by giving the EN the status of a national standard and by withdrawing any national s
7、tandards conflicting with the EN. Edition approved for publication 31 March 2013 Comments should be sent within six months after the date of publication to ASD-STAN Metallic Material Domain Copyright 2013 by ASD-STAN prEN 4826:2013 (E) 2 Contents Page Foreword 2 1 Scope 3 2 Normative references 3 3
8、Terms and definitions .4 4 Purpose of process .4 5 Applicability and limitations of the process .5 6 Coating system classification 5 6.1 System types 5 6.2 Coating thicknesses 6 7 Requirements .6 7.1 Process requirements .6 7.2 Main technical engineering requirements .8 8 Quality requirements .10 8.
9、1 Approval of the processor 10 8.2 Process approval .11 8.3 General points 11 8.4 Periodic tests .11 8.5 Periodic chemical analysis .12 8.6 Parts acceptance controls 12 9 Designation 13 Foreword This standard was reviewed by the Domain Technical Coordinator of ASD-STANs Metallic Material Domain. Aft
10、er inquiries and votes carried out in accordance with the rules of ASD-STAN defined in ASD-STANs General Process Manual, this standard has received approval for Publication. prEN 4826:2013 (E) 3 1 Scope This standard specifies the plating of a Zinc-Nickel (12 % to 16 %) alloy on mechanical parts and
11、 fasteners in steels (UTS 1 450 MPa), stainless steels (UTS 1 450 MPa), copper alloys and aluminium alloys (not applicable for electrical components), as well as the passivation and lubricant finishing that can be associated to them. The Zinc-Nickel process is an electrolytic plating process under c
12、ontrolled current allowing to deposit a Zinc-Nickel layer from, most often, an alkaline electrolyte. Alkaline Zinc-Nickel is only considered in this standard. The purpose of this standard is to give technical and quality requirements of Zinc-Nickel plating. It doesnt give complete in-house process i
13、nstructions, these shall be given in the manufacturers detailed process instructions. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of
14、the referenced document (including any amendments) applies. EN 2832, Aerospace series Hydrogen embrittlement of steels Notched specimen test EN 4473, Aerospace series Aluminium pigmented coatings for fasteners Technical specification EN 9100, Quality Management Systems Requirements for Aviation, Spa
15、ce and Defence Organizations EN ISO 1463, Metallic and oxide coatings Measurement of coating thickness Microscopical method (ISO 1463:2003) EN ISO 2409, Paints and varnishes Cross-cut test (ISO 2409:2007) EN ISO 2819, Metallic coatings on metallic substrates Electrodeposited and chemically deposited
16、 coatings Review of methods available for testing adhesion (ISO 2819:1980) EN ISO 3497, Metallic coatings Measurement of coating thickness X-ray spectrometric methods (ISO 3497:2000) EN ISO 9227, Corrosion tests in artificial atmospheres Salt spray tests (ISO 9227:2006) ISO 2812 (all parts), Paints
17、and varnishes Determination of resistance to liquids NASM 1312-5, Fastener test methods Method 5: Stress durability 1)NASM 1312-14, Fastener test methods Method 14: Stress durability internally threaded fasteners 1)ASTM F 519, Standard test method for mechanical hydrogen embrittlement evaluation of
18、plating/coating processes and service environments 2)1) Published by: AIA National (US) Aerospace Industries Association of America http:/www.aia-aerospace.org/ 2) Published by: ASTM National (US) American Society for Testing and Materials http:/www.astm.org/ prEN 4826:2013 (E) 4 3 Terms and definit
19、ions For the purposes of this document, the following terms and definitions apply. 3.1 batch unless otherwise specified, it comprises parts of the same type (shape, size, material), processed at the same time in the same bath with the same de-embrittlement conditions 3.2 pre-production part part rep
20、resentative of future production 3.3 electro-plating electrolytical metal deposition 3.4 passivation conversion performed on metal electro-deposition in order to improve corrosion resistance 3.5 lubricant top coat /finishing additional thin organic or inorganic resin based layer in order to improve
21、functional properties: friction 3.6 Zinc-Nickel coating system Zinc-Nickel coating including: possible undercoat as strike, supplementary treatments as passivation and/or lubricant top coat. See 6.1: type 1 to type 4. 3.7 substrate material upon which a coating is directly deposited, in the case of
22、a single or first coating, the substrate is identical with the basis metal and for a subsequent coating, the intermediate coating is the substrate 3.8 UTS Ultimate Tensile Strength 3.9 nodule rounded projection formed on a cathode during electrode position (2.5) that may be seen without magnificatio
23、n 4 Purpose of process The aim of the Zinc-Nickel plating is to ensure a protection against corrosion for steels or to reduce the effects of galvanic coupling of less noble materials in contact with the plated substrates. For improving corrosion, a passivation is performed on Zinc-Nickel coating. Th
24、e Zinc-Nickel plating has also electrical conductivity properties and may also provide anti-galling properties when associated with an appropriate lubricant finishing. prEN 4826:2013 (E) 5 5 Applicability and limitations of the process This standard applies whenever referenced. It is applicable on p
25、arts with or without threads, and fasteners, and on: low alloys steels and stainless steels UTS 1 450 MPa, copper alloys, nickel alloys, aluminium alloys. The electrolytic Zinc-Nickel plating process must not be used in the following cases: welded parts likely to entrap electrolyte, cavities, holes,
26、 recesses for which processing limitations may result in uncontrolled or incomplete, coverage, springs with diameter 1 mm. Zinc-Nickel plating can withstand the following service temperatures: 120 C for parts coated with lubricant top coat, 250 C for parts coated with trivalent chromium passivation.
27、 6 Coating system classification 6.1 System types Zinc-Nickel coating system is classified by the four following types, depending on the supplementary finishing: Type 1 (T1): Zinc-Nickel (12 % to 16 %) alloy as plated. Type 2 (T2): Zinc-Nickel (12 % to 16 %) alloy as plated and trivalent chromium pa
28、ssivation in order to improve corrosion resistance. Type 3 (T3): Zinc-Nickel (12 % to 16 %) alloy as plated, trivalent chromium passivation and friction control lubricant for improving corrosion resistance and reaching consistent coefficient of friction of 0.08 to 0.14. Type 4 (T4): Zinc-Nickel (12
29、% to 16 %) alloy as plated, trivalent chromium passivation and friction control lubricant for improving corrosion resistance and reaching consistent coefficient of friction of 0.12 to 0.18. prEN 4826:2013 (E) 6 6.2 Coating thicknesses Unless otherwise specified in the product standard or definition
30、document, the coating thicknesses are as follows: Class A: 4 m to 7 m typical thickness for screws with diameter 3,5 mm). Class C: 10 m to 20 m (typical thickness for other cases for maximum corrosion resistance). It is permissible that thicknesses obtained on parts exceed the maximum thickness valu
31、es given above provided that the final sizes required by the plan and drawings are satisfied and that the thickness is not exceeding 20 % of the maximum thickness. For internally threaded parts, a maximum limit of 13 m (class B) above the minimum shall be allowed on the external surfaces. The thickn
32、ess tolerances are those of the Zinc-Nickel electrolytic plating (type 1) and/or Zinc-Nickel coating system (type 2, 3 and 4): Possible undercoat (e.g. strike in order to improve adhesion on stainless steels), Passivation and lubricant finishing thicknesses are considered to be insignificant. For fa
33、steners, the possible undercoat, the passivation or lubricant finishing thicknesses shall not alter mountability, see dimensional test, subclause 8.3. 7 Requirements 7.1 Process requirements 7.1.1 Information for the processor process designation, see Clause 9; bare substrate standard reference and
34、heat treatment; areas to be plated; plated thickness measuring points; duration and temperature of stress relief and de-embrittlement treatments; electrical contact points or areas where these are not permitted; specification for testing on parts and/or samples. 7.1.2 Condition of parts prior to the
35、 treatment Welding, soldering/brazing, mechanical operations and heat treatments shall have been completed. Stress relief may be required for parts which have been cold worked or machined after the heat treatment operation. When shot peening is specified, it shall be performed after the stress relie
36、f operations. prEN 4826:2013 (E) 7 Unless otherwise specified, the stress relief heat treatment conditions for parts in steel shall conform to Table 1. Table 1 Stress relief heat treatment of parts in steel UTS Stress relief heat treatment MPa 1 100 Not necessary 1 100 and 1 450 (190 to 230) 10 C, 1
37、 h min. A slight discoloration of the surface by oxidation is admissible after stress relief. 7.1.3 Process conditions a) Tooling The tools, bars, electrical contact systems, and metal masking tooling must be protected against corrosion, and/or free of corrosion or any other damage which may be detr
38、imental to the treatment during use. The part racks and tools must be designed and set up in such a manner as to: avoid any retention of air or treatment solution in the parts, facilitate neutralization and removal of solutions during rinsing operations, assure electrical contact for the electrolyti
39、c baths, avoid the treatment any accidental contact between the parts to be treated and the tank equipments or electrodes, and between the different parts. Avoid any galvanic damage between tools and parts. b) Masking The parts shall be previously degreased prior to masking. Component areas which mu
40、st not be coated shall be masked with suitable material. c) Surface pre-treatment Surface preparation means any method able to completely eliminate all surface contaminations. Methods which may result in hydrogen embrittlement of the material shall be avoided. The surface preparation prior to Zinc-N
41、ickel plating that guides the plating adhesion depends on the metallic substrate; for aluminium alloys, copper alloys and stainless steels a strike undercoat may be performed. d) Zinc-Nickel plating The Zinc-Nickel shall be deposited in accordance with an approved electrolyte and processor to produc
42、e coatings containing 12 % to 16 % nickel. The composition of the bath as well as the process parameters shall be chosen such that the requirements for the Zinc-Nickel coating specified by this standard (see 7.2) could be met. prEN 4826:2013 (E) 8 Addition agents shall have no negative effect on the
43、 hydrogen embrittlement behaviour. Treatment can be performed by racking or barrel. Before part immersion, it is essential to ensure that the electrical contacts are correct (cleanliness of bars and contacts). During part immersion in bath, power supply shall be switched off. e) Passivation Items sh
44、all be passivated immediately after plating or after baking if applicable. The supplementary passivation for corrosion performance shall be if possible chromate free. f) De-embrittlement De-embrittlement shall be carried out within 4 h after Zinc-Nickel plating, in accordance with Table 2. Table 2 D
45、e-embrittlement Substrate Temperature a Minimum duration a C h Steels 1 100 MPa UTS 1 450 MPa (190 to 230) 10 C 8 Other materials UTS 1 100 MPa Not required aOther conditions may be used subject to agreement between the processor and the purchaser. NOTE When the strength resistance is defined by a r
46、ange (for example 1 000 MPa to 1 150 MPa), the value to be considered for de-embrittlement conditions, is the highest one of the range (1 150 MPa in the case of the example). g) Lubricant finishing It should be applied by immersion or by spray on clean items. The lubricant is applied after de-embrit
47、tlement or passivation within the delay allowing to avoid the damage of the passivation layer. Electrical properties might be affected by the lubricant finishing. h) Stripping Both electrochemical and chemical processes may be applied. The stripping variants used, however, shall not deteriorate the
48、dimensions, surface finish and mechanical properties of parts. In particular, it shall not result in embrittlement of the metallic substrate. Reprocessing of parts depends on the material and may only be carried out following confirmation and requirements by the manufacturer. 7.2 Main technical engi
49、neering requirements 7.2.1 General The final coating is expected to meet the following main requirements: adequate appearance of Zinc-Nickel plating, of passivation and of lubricant finishing when applicable, a good adhesion of Zinc-Nickel coating to the substrate, of lubricant finishing on Zinc-Nickel plating when applicable, of the subsequent paint to the Zinc-Nickel coating system, adequate thickness according required range on draw
