1、AECMA STANDARD NORME AECMA AECMA NORM prEN 2516 Edition I January 1996 PUBLISHED BY THE EUROPEAN ASSOCIATION OF AEROSPACE INDUSTRIES (AECMA) Gulledelle 94 - B-I 200 BRUXELLES - Tel. (32) 2 775 81 10 - Fax. (32) 2 775 81 11 ICs : 49.040.40 Descriptors : Aircraft industry, corrosion resistant steels,
2、decontamination, nickel alloys ENGLISH VERSION Aerospace series Passivation of corrosion resistant steels and decontamination of nickel base alloys Srie arospatiale Passivation des aciers resistant la corrosion et dcontamination des alliages base nickel Luft- und Raumfahrt Passivieren von korrosions
3、bestndigen Sthlen und Dekontaminierung von Nickellegierungen This “Aerospace series“ Standard has been drawn up under the responsibility of AECMA (The European Association of Aerospace Industries). It is published on yell0 w paper in three equivalent versions (English, French, German). It will be su
4、bmitted as a draft European Standard to CEN (European Committee for Standardization) for formal vote. Edition approved for publication - 1996-01-31 _- The equivalent versions in French and German languages can be supplied by B.N.A.E. - Technopolis 54 - 199, rue Jean-Jacques Rousseau 921 38 ISSY - LE
5、S - MOULINEAUX CEDEX - FRANCE Page 3 EN 2516 : 1996 1 Scope This standard specifies several chemical methods of passivation for corrosion resistant steels (austenitic, ferritic, martensitic and precipitation hardenable) and of decontamination for nickel base alloys. 2 Purpose of process To improve t
6、he corrosion resistant characteristics of a part after such treatments as machining, forming, tumbling and shot peening by removing foreign metal contamination due to these operations. Passivation shall not be used on castings, welded or brazed parts, carburized or nitrided surfaces nor on parts wit
7、h mating surfaces when entrapment of acids may occur. 3 Normative references This European Standard incorporates by 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
8、 dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. IS0 9227 Corrosion tests in artificial atmosp
9、heres - Salt spray tests EN 2000 Aerospace series - Quality assurance - EN aerospace products - Approval of the quality system of manufacturers Aerospace series - Metallic materials - Part 1 : Designation 2, EN 2032-1 4 Classification The process class to be used depending on the material type unles
10、s otherwise specified between the manufacturer and the purchaser is given in table 1. The designation of the material type is defined in EN 2032-1. 1 ) Other processes (e.g. electrolytic polishing) can also produce passivated surfaces. 2) Published as AECMA Prestandard at the date of publication of
11、this standard Previous page is blank STD-AECMA PREN 25Lb-ENGL 199b 1012311 0011205 4b4 Page 4 EN 2516 : 1996 Material type and designation Austenitic chromium-nickel steels and austeno-ferritic steels FE-PA36XX, FE-PA39XX, FE-PA45XX, FE-PA47XX, FE-PA48XX, FE-PA49XX,FE-PA15XX Table 1 Process class C1
12、 orC2 I I i Ferritic and martensitic chromium steels FE-PM15XX8 FE-PM17XX, FE-PM19XX Austenitic precipitation hardenable steels Martensitic precipitation hardenable steels High chromium martensitic steels Heat resisting nickel base alloys FE-PA26XX8 FE-PA29XX, FE-PA25XX FE-PM27XX, FE-PM38XX, FE-PM35
13、XX FE-PM39XX NI-PH 1 3XX, NI-PH18XX, NI-PH23XX8 NI-PH29XX, NI-PD73XXr NI-PH26XX c4 c1 c4 c3 C1 orC2 5 Information for the processor - Designation, see 12 ; - reference of the material standard and metallurgical condition of the latter ; - sequence of operations, if necessary ; - areas to be processe
14、d. 6 Condition of the parts prior to processing Fabrication of the parts shall have been completed. 7 Pre-treatments The parts shall be submitted to one or more of the processes (7.1 to 7.4) appropriate to their degree of contamination. These processes are given for guidance. Other methods giving at
15、 least equivalent results may be applied. Unless otherwise specified, parts shall be processed from one step to the next without delay. 7.1 Degreasing 7.1.1 Organic solvents Approved products shall be used either cold in liquid state or hot in vapour state. STD-AECMA PREN 25Lb-ENGL Lb LOL23LL 001L?r
16、lL, 3TrJ IW Page 5 EN 2516 : 1996 7.1.2 Alkaline solutions a) The composition may be as follows : Degreasing in strong alkaline solutions : - sodium hydroxide : 15 gll - sodium metasilicate pentahydrate : 40 g/l b The composition may be as follows : Degreasing in mild alkaline solutions : - sodium m
17、etasilicate pentahydrate : 25 gll - sodium carbonate : 25 gll Addition of a wetting agent is possible. These solutions shall be used for immersion degreasing either anodically or not. 7.2 Abrasive cleaning a) Blasting Use a fine-grain alumina or glass beads with or without water. b) Tumbling The abr
18、asives shall not have been used on any other type of matei., base alloys. (see ta,! 1) except i tar lum 7.3 Descaling The method shall be chosen according to the type of parts, heat treatment or hot forming. 7.4 Acid-pickling It shall only be used on steels not susceptible to pitting or sensitive to
19、 intergranular corrosion by the pickling solution which is most frequently an aqueous solution of nitric and hydrofluoric acids. The concentration can be adjusted within very wide limits by varying the proportions of the ingredients and by adjusting solution temperatures. Parts in steel of Rm (max.)
20、 1 100 MPa 3, shall be de-embrittled by heat treatment at 190 OC to 230 OC for at least 1 h. 3) Rm (max.) = maximum specified Rm - .- STD-AECMA PREN 25Lb-ENGL L77b = LOL23LL OOLL207 237 W Page 6 EN 2516 : 1996 8 Treatment The aqueous solutions shall be chosen from table 2 in accordance with the proc
21、ess class defined in table 1 for the material used to manufacture the parts. The parts shall be completely immersed in the chosen solution, then rinsed in clean water and dried. Table 2 Process class I I c2 I Step a) shall bc followed by step b) with a clean water rinse in between. 9 Required charac
22、teristics and inspection 9.1 Parts 9.1.1 Appearance When subjected to visual inspection, the surfaces shall be clean and free from corrosion, pitting or other form of surface attack due to the treatment. A slight discolouration is allowed. 9.1.2 Absence of iron Contamination Surfaces of type parts o
23、r test specimens shall not show any iron contamination indicated by rust after a salt spray test according to IS0 9227 for 2 h. 9.2 Process 9.2.1 Air used for drying or any other operation shall be dry and free from oil. 9.2.2 content less than 0,l g/l. The iron content in the solutions indicated in
24、 table 2 shall be less than 5 g/l and the chloride The nitric acid and sodium dichromate concentration shall be within the limits indicated in table 2. Chemical analyses of the solutions indicated in table 2 shall be carried out at regular intervals to determine the contents of nitric acid, sodium d
25、ichromate, chloride and iron. STD*AECMA PREN 25Lb-ENGL L77b 101231l 001L208 173 = Page 7 EN 2516 : 1996 10 Quality assurance 1 O. 1 See EN 2000. Approval of the processor 10.2 Process qualification Before beginning production, the processor shall submit a series of type parts and test pieces from th
26、e first batch treated under series conditions, which shall be tested according to 9.1. If the process is different from that described in this standard, it shall be qualified as follows : At least one specimen of each material type to which the process is applicable (see table 11, with a surface rou
27、ghness of Ra 5 1,6 pm, shall be treated according to the process to be qualified. After visual inspection to 9.1.1 each specimen shall be subjected to a salt spray test in accordance with IS0 9227 for 24 h. The exposed surface shall then show not more than a few isolated spots of rust. 10.3 Acceptan
28、ce The parts shall have the required characteristics (see 9.1 1. Frequency of inspection shall be agreed between the purchaser and processor. 10.4 Fault sanction The parts not meeting the requirements shall be rejected. After agreement of the purchaser, these parts may be reprocessed (see 7 and 81.
29、11 Health, safety and environmental aspects The locally applicable regulations and laws shall be observed. 12 Designation EXAMPLE : EN251 6C1 Process class (see table 1) Number of this standard NOTE : If the classes of this standard are not used (see 4), the designation shall be limited to EN 2516.
