1、CEN PRENu3752 94 3404589 0080987 L2T H Edition approved for publication AECMA STANDARD NORME AECMA AECMA NORM Comments should be sent within six months C8 Chairman after the date of publication to prEN 3752 Edition P 1 December 1994 DIT PAR LASSOCIATION EUROPENNE DES CONSTRUCTEURS DE MATRIEL AROSPAT
2、IAL Technopolis - 175, rue Jean-Jacques Rousseau - F-92138 Issy-les-Moulineaux Cedex - Tl. (1) 47.36.98.76 UDC : Descriptors : ENGLISH VERSION Aerospace series Nuts,self -locking, M J threads, in heat resisting steel FE-PA92HT (A286), Mos2 coated Classification : i 100 MPa (at ambient temperature) /
3、 425 OC Technical specification Srie arospatiale Luft- und Raumfahrt crous, freinage interne, filetage MJ, en acier rsistant chaud FE-PA92HT (A2861, Muttern, selbstsichernd, MJ-Gewinde, aus hochwarmfestem Stahl FE-PA92HT (A2861, revtus Mos2 Mos2 beschichtet Classification : 1 100 MPa Klasse : 1 100
4、MPa ( temperature ambiante) / 425 OC (bei Raumtemperatur) I425 OC Spcification technique Technische Lieferbedingungen This “Aerospace Series“ Prestandard has been drawn up under the responsibility of AECMA (Association Europenne des Constructeurs de Matriel Arospatial). It is published on green pape
5、r for the needs of AECMA-Members. It has been technically approved by the experts of the concerned Technical Committee following comment by the Member countries. Subsequent to the publication of this Prestandard, the technical content shall not be changed to an extent that interchangeability is affe
6、cted, physically or functionally, without re-identification of the standard. After examination and signature of the AECMA Standard Checking Centre (NPS) and formal agreement of the Official Services of the Member countries it will be submitted as a draft European Standard to CEN European Committee f
7、or Standardization) for formal vote. 1994-1 2-1 6 AECMA Technopolis - 175, rue Jean-Jacques Rousseau 92 138 Issy-les-Moulineaux Cedex - FRANCE Mr Williams 0 aecma 1994 Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo r
8、eproduction or networking permitted without license from IHS-,-,-CEN PRENt3752 94 3404589 0080988 066 Page 2 prEN 3752 : 1994 Contents list 1 Scope 2 Normative references 3 Definitions 4 Quality assurance 5 Requirements Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provid
9、ed by IHS under license with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-CEN PREN*3752 94 3404589 0080787 TT2 Page 3 prEN 3752 : 1994 1 Scope This standard specifies the characteristics, qualification and acceptance requirements for self-locking nuts with
10、MJ threads in FE-PA92HT, Mos2 coated. Classification 1 100 MPa I425 OC 2). It is applicable whenever referenced. 2 Normative references IS0 2859-1 IS0 3452 IS0 3534-1 977 IS0 4288 IS0 5855-2 IS0 7481 EN 2491 EN 3042 ASTM EI 12-88 Sampling procedures for inspection by attributes - Part 1 : Sampling p
11、lans indexed by acceptable quality level (AQL) for lot-by-lot inspection Non destructive testing - Penetrant inspection - General principles Statistics - Vocabulary and symbols Rules and procedures for the measurement of surface roughness using stylus instruments Aerospace - MJ threads - Part 2 : Li
12、mit dimensions for bolts and nuts Aerospace - Fasteners - Self-locking nuts with maximum operating temperature less than or equal to 425 OC - Test methods Aerospace series - Molybdenum disulphide dry lubricants - Coating methods 3, Aerospace series - Quality assurance - EN aerospace products - Quali
13、fication procedure Standard Test Methods for Determining Average Grain size 4, 1) Corresponds to the minimum tensile stress which the nut is able to withstand at ambient temperature without breaking or cracking when tested with a bolt of a higher strength class. 2) Maximum test temperature of the pa
14、rts 3) In preparation at the date of publication of this standard 4) Published by : American Society for Testing and Materials (ASTM), 1916 Race street, Philadephia, PA 19103, USA Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot fo
15、r ResaleNo reproduction or networking permitted without license from IHS-,-,-CEM PREN*3752 94 3404589 0080970 714 Page 4 prEN 3752 : 1994 3 Definitions For the purposes of this standard, the following definitions apply : 3.1 Production batch Quantity of finished nuts manufactured, using the same pro
16、cess, from a single material cast (single heat of alloy), having the same number (of product standard or definition document), thread code and diameter, heat treated together to the same specified condition and produced as one continuous run. 3.2 Inspection lot Quantity of nuts from a single product
17、ion batch with the same number (of product standard or definition document) which completely defines the nut. 3.3 Discontinuities 3.3.1 Crack : Rupture in the material which may extend in any direction and which may be intercrystalline or transcrystalline in character. 3.3.2 Seam : Open surface defe
18、ct 3.3.3 forging them into the surface. Lap : Surface defect caused by folding over metal fins or sharp corners and then rolling or 3.3.4 particles may be isolated or arranged in strings. Inclusions : Non-metallic particles originating from the material manufacturing process. These 3.4 Test temperat
19、ure Ambient temperature, unless otherwise specified 3.5 Simple random sampling The taking of n items from a population of N items in such a way that ali possible combinations of n items have the same probability of being chosen 5). 3.6 Critical defect A defect that, according to judgement and experi
20、ence, is likely to result in hazardous or unsafe conditions for individuals using, maintaining, or depending upon the considered product, or that is likely to prevent performance of the function of a major end item l. 3.7 Major defect A defect other than critical, that is likely to result in a failu
21、re or to reduce materially the usability of the considered product for its intended purpose ). 3.8 Minor defect A defect that is not likely to reduce materially the usability of the considered product for its intended purpose, or that is a departure from established specification having little beari
22、ng on the effective use or operation of this product 5). 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-,-,-CEN PRENx3752 94 3404589 0080993 b50 E Page 5
23、prEN 3752 : 1994 3.9 Sampling plan A plan according to which one or more samples are taken in order to obtain information and possibly to reach a decision 5). 3.10 Limiting quality In a sampling plan, the quality level which corresponds to the specified 10 % probability of acceptance. 3.1 1 Acceptab
24、le quality level (AQL) A quality level which in a sampling plan corresponds to a specified but relatively high probability of acceptance. It is the maximum per cent defective (or the maximum number of defects per hundred units) that, for purposes of sampling inspection can be considered satisfactory
25、 as a process average 3.12 Finished nut A nut ready for use , inclusive of any possible treatments and/or surface coatings, as specified in the product standard or definition document. 3.13 Definition document Document specifying all the requirements for finished nuts 3.14 Self-locking torque The to
26、rque to be applied to the nut or bolt to maintain its movement of rotation in relation to the associated part, the assembly being under no axial load and the nut locking system being completely engaged with the bolt (minimum protrusion of two pitches, including the end chamfer). 3.15 Seating torque
27、The tightening torque to be applied to the nut or bolt to introduce or to increase the axial load in the assembly. 3.16 Unseating torque The untightening torque to be applied to the nut or bolt to reduce or remove the axial load in the assembly. 3.17 Breakaway torque The torque required to start uns
28、crewing the nut or bolt with respect to the associated part, with the nut locking device still fully engaged on the bolt, but after the axial load in the assembly has been removed by unscrewing half a turn followed by a halt in rotational movement. 3.18 Wrench feature torque The torque to be applied
29、 to the wrenching feature of the nut. 5) Definition taken from IS0 3534 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-,-,-CEN PRENr3752 94 W 3404589 O080
30、992 597 D Page 6 prEN 3752 : 1994 4 Quality assurance 4.1 Qualification EN 3042 Qualification inspections and tests (requirements, methods, numbers of nuts) are specified in table 1. They shall be carried out on : - each type and diameter of nut ; - 46 nuts selected from a single inspection lot by s
31、imple random sampling. The test programme may possibly be reduced, or the qualification of a nut be granted without inspection or testing : any such decision shall be based on the results obtained on similar types and diameters of nuts provided that the design and manufacturing conditions are identi
32、cal. Table 2 indicates the allocation of nut specimens for the inspections and tests. 4.2 Acceptance 4.2.1 Purpose The purpose of acceptance inspections and tests is to check, as simply as possible, by a method representative of actual use conditions, with the uncertainty inherent to statistical sam
33、pling, that the nuts constituting the batch satisfy the requirements of this standard. 4.2.2 Conditions Acceptance inspections and tests (requirements, methods, numbers of nuts) are specified in table 1 ; they shall be carried out on each production batch or inspection lot. Nuts from the batch or lo
34、t to be tested shall be selected by simple random sampling. Each nut may be submitted to several inspections or tests. If a more stringent inspection is deemed necessary, all or part of the qualification inspections and tests may be performed during the acceptance inspection and testing. In this cas
35、e, the number of nuts submitted to these inspections and tests is the same as that submitted for qualification inspection and tests. 4.2.3 Responsibility Acceptance inspections and tests shall be carried out by the manufacturer, or under his responsibility. 4.2.4 Inspection and test report A test re
36、port showing actual numerical values shall be provided if specified in the purchase order. 5 Requirements See table 1. Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking permitted without licen
37、se from IHS-,-,-I Inspection and test method :hemical analysis of .ertificate of conformity ssued by the manufacturer if the semi-finished product ;tandard gauging CEN PRENa3752 94 3404589 0080993 423 M Clause 5.1 5.2 5.3 - 5.3.1 - 5.3.2 5.3.2.1 Page 7 prEN 3752 : 1994 Table 1 - Technical requiremen
38、ts and test methods :haracteristic naterial limensions, olerances and olerances of orm and iosition ulanufacturing -arming Heat treatment Solution and precipitation heat treatmer Requirement i accordance with the product tandard or definition document n accordance with the product ;tandard or defini
39、tion document Juts shall be formed by a hot or :old forming process. f hot formed, the forming :emperahre shall not exceed I 150 OC and they shall be air :ooled or faster. The equipment shall ensure a Jniform temperature throughout the production batch. The heat treatment medium or atmosphere shall
40、not cause any surface contamination except as permitted by 5.5.5. Any scale which will not be removed by subsequent machining shall be removed by abrasive blasting. Solution treat (if applicable) at a temperature of 900 OC to 980 OC held at the selected temperature within I 15 OC for between 1 h min
41、. and 2 h max. quench in oil, or alternative medium or faster. Precipitation treat at 720 OC + 10 OC held at temperature for 16 h I 15 min cooled in air or faster. The method of forming shall )e indicated. Calibration of the heat treatment equipment shall be confirmed. Appropriate equipment LIA I O
42、A - - Q A - O 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-,-,-Page 8 prEN 3752 : 1994 Inspection and test method Table 1 (continued) QIA ) - Clai 5.3.3
43、 - 5.3.4 5.3.5 5.3.6 See EN 2491. 3.4 - O A Characteristic Bearing surface perpendicularity Thread deformation (form out of round) Surface roug hness Surface coating Mechanical properties Requirement In accordance with the product standard or definition document. For non-floating plate nuts having a
44、 bearing surface exceeding 1,5 times the thread nominal diameter, the perpendicularity requirement shall, unless otherwise specified by the product standard or definition document, apply only to that portion of the bearing surface of the part contained within a diameter equal to 1,5 times the thread
45、 nominal diameter. Threads in the locking region may be deformed in any manner provided that the nut meets the requirements of this standard. Any tool marks shall blend smoothly without any abrupt changes. The finished nuts shall allow the “GO“ thread plug gauge to enter a minimum of three turns bef
46、ore engagement of the locking element for nuts having overall length of thread portion not less than 1,2 times the nominal thread diameter. After coating a bolt with IS0 5855-2 threads shall be able to be hand threaded 1,5 turns minimum in the nut. Finished nuts having shorter threaded portion shall
47、 allow the “GO“ thread plug gauge to enter a minimum of three quarters of a turn. In accordance with the product standard or definition document prior to surface coating In accordance with the product standard or definition document A test sample shall be selected from each size of bar, wire, sheet
48、or strip taken from each cast, and shall be heat treated together with a production batch of nuts. The sample selected shall be sufficient to provide tensile test pieces. The test pieces shall meet the mechanical properties required by the material standard. SO 7481 l-3- t+ IS0 4288 - Visual :xamina
49、tion ;ample size 46 Tables 3 and 4 46 Tables 3 and 4 3 Tables 3 and 4 43 Tables 3 and 4 (continued) 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-,-,- Clau - 5.4.1 5.4.1. 5.4.1. 5.4.2 5.4.3 5.4.3. CEN PRENx3752 94 3404589 0080995 2Tb Page 9 prEN 3752 : 1994
