EN 3752:2003
(Main)Aerospace series - Nuts, self-locking, MJ threads, in heat resisting steel FE-PA92HT (A286), MoS2 coated - Classification: 1 100 MPa (at ambient temperature) / 425°C - Technical specification
Aerospace series - Nuts, self-locking, MJ threads, in heat resisting steel FE-PA92HT (A286), MoS2 coated - Classification: 1 100 MPa (at ambient temperature) / 425°C - Technical specification
This standard specifies the characteristics, qualification and acceptance requirements for self-locking nuts with MJ threads in FE-PA92HT, MoS2 coated.
Classification 1 100 MPa ) / 425 °C )
It is applicable whenever referenced.
Aerospace series - Nuts, self-locking, MJ threads, in heat resisting steel FE-PA92HT (A286), MoS2 coated - Classification: 1 100 MPa (at ambient temperature) / 425°C - Technical specification
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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Aerospace series - Nuts, self-locking, MJ threads, in heat resisting steel FE-PA92HT (A286), MoS2 coated - Classification: 1 100 MPa (at ambient temperature) / 425°C - Technical specificationAerospace series - Nuts, self-locking, MJ threads, in heat resisting steel FE-PA92HT (A286), MoS2 coated - Classification: 1 100 MPa (at ambient temperature) / 425°C - Technical specification49.030.30MaticeNutsICS:Ta slovenski standard je istoveten z:EN 3752:2003SIST EN 3752:2004en01-maj-2004SIST EN 3752:2004SLOVENSKI
STANDARD
SIST EN 3752:2004
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 3752January 2003ICS 49.030.30English versionAerospace series - Nuts, self-locking, MJ threads, in heatresisting steel FE-PA92HT (A286), MoS2 coated -Classification: 1 100 MPa (at ambient temperature) / 425°C -Technical specificationThis European Standard was approved by CEN on 2 June 2002.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the 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 translationunder the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and UnitedKingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2003 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 3752:2003 ESIST EN 3752:2004
EN 3752:2003 (E)2ContentspageForeword.31Scope.32Normative references.33Definitions.43.1Production batch.43.2Inspection lot.43.3Discontinuities.43.4Test temperature.43.5Simple random sampling.43.6Critical defect.43.7Major defect.43.8Minor defect.53.9Sampling plan.53.10Limiting quality.53.11Acceptable quality level (AQL).53.12Finished nut.53.13Definition document.53.14Self-locking torque.53.15Seating torque.53.16Unseating torque.53.17Breakaway torque.53.18Wrench feature torque.64Quality assurance.64.1Qualification.64.2Acceptance.65Requirements.7SIST EN 3752:2004
EN 3752:2003 (E)3ForewordThis document (EN 3752:2003) has been prepared by the European Association of Aerospace Manufacturers –Standardization (AECMA-STAN).After enquiries and votes carried out in accordance with the rules of this Association, this Standard has receivedthe approval of the National Associations and the Official Services of the member countries of AECMA, prior to itspresentation to CEN.This European Standard shall be given the status of a national standard, either by publication of an identical text orby endorsement, at the latest by July 2003, and conflicting national standards shall be withdrawn at the latest byJuly 2003.According to the CEN/CENELEC Internal Regulations, the national standards organizations of the followingcountries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal,Slovakia, Spain, Sweden, Switzerland and the United Kingdom.1 ScopeThis standard specifies the characteristics, qualification and acceptance requirements for self-locking nuts with MJthreads in FE-PA92HT, MoS2 coated.Classification 1 100 MPa 1) / 425 °C 2)It is applicable whenever referenced.2 Normative referencesISO 2859-1Sampling procedures for inspection by attributes – Part 1: Sampling schemes indexed byacceptance quality limit (AQL) for lot-by-Iot inspectionISO 3452Non destructive testing – Penetrant inspection – General principlesISO 3534Statistics – Vocabulary and symbolsISO 4288Geometrical Product Specifications (GPS) – Surface texture: Profile method – Rules andprocedures for the assessment of surface textureISO 5855-2Aerospace – MJ threads – Part 2: Limit dimensions for bolts and nutsISO 7481Aerospace – Nuts, self-locking, with maximum operating temperature less than or equal to425 °C – Test methodsEN 2491Aerospace series – Molybdenum disulphide dry lubricants – Coating methodsEN 3042Aerospace series - Quality assurance - EN aerospace products - Qualification procedure
1)Corresponds to the minimum tensile stress which the nut is able to withstand at ambient temperature without breaking orcracking when tested with a bolt of a higher strength class.2)Maximum test temperature of the partsSIST EN 3752:2004
EN 3752:2003 (E)4ASTM E112-88Standard Test Methods for Determining Average Grain size 3)3 DefinitionsFor the purposes of this standard, the following definitions apply:3.1 Production batchQuantity of finished nuts manufactured, using the same process, from a single material cast (single heat of alloy),having the same number (of product standard or definition document), thread code and diameter, heat treatedtogether to the same specified condition and produced as one continuous run.3.2 Inspection lotQuantity of nuts from a single production batch with the same number (of product standard or definition document)which completely defines the nut.3.3 Discontinuities3.3.1 Crack : Rupture in the material which may extend in any direction and which may be intercrystalline ortranscrystalline in character.3.3.2 Seam : Open surface defect3.3.3 Lap : Surface defect caused by folding over metal fins or sharp corners and then rolling or forging them intothe surface.3.3.4 Inclusions : Non-metallic particles originating from the material manufacturing process. These particlesmay be isolated or arranged in strings.3.4 Test temperatureAmbient temperature, unless otherwise specified3.5 Simple random samplingThe taking of n items from a population of N items in such a way that all possible combinations of n items have thesame probability of being chosen 5)3.6 Critical defectA defect that, according to judgement and experience, is likely to result in hazardous or unsafe conditions forindividuals using, maintaining, or depending upon the considered product, or that is likely to prevent performance ofthe function of a major end item 5).3.7 Major defectA defect other than critical, that is likely to result in a failure or to reduce materially the usability of the consideredproduct for its intended purpose 5)
3)Published by: American Society for Testing and Materials (ASTM), 1916 Race street, Philadephia, PA 19103, USASIST EN 3752:2004
EN 3752:2003 (E)53.8 Minor defectA defect that is not likely to reduce materially the usability of the considered product for its intended purpose, orthat is a departure from established specification having little bearing on the effective use or operation of thisproduct 5).3.9 Sampling planA plan according to which one or more samples are taken in order to obtain information and possibly to reach adecision 4).3.10 Limiting qualityIn a sampling plan, the quality level which corresponds to the specified 10 % probability of acceptance.3.11 Acceptable 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 ofsampling inspection can be considered satisfactory as a process average 5).3.12 Finished nutA nut ready for use, inclusive of any possible treatments and/or surface coatings, as specified in the productstandard or definition document.3.13 Definition documentDocument specifying all the requirements for finished nuts3.14 Self-locking torqueThe torque to be applied to the nut or bolt to maintain its movement of rotation in relation to the associated part, theassembly being under no axial load and the nut locking system being completely engaged with the bolt (minimumprotrusion of two pitches, including the end chamfer).3.15 Seating torqueThe tightening torque to be applied to the nut or bolt to introduce or to increase the axial load in the assembly.3.16 Unseating torqueThe untightening torque to be applied to the nut or bolt to reduce or remove the axial load in the assembly.3.17 Breakaway torqueThe torque required to start unscrewing the nut or bolt with respect to the associated part, with the nut lockingdevice still fully engaged on the bolt, but after the axial load in the assembly has been removed by unscrewing halfa turn followed by a halt in rotational movement.
4)Definition taken from ISO 3534SIST EN 3752:2004
EN 3752:2003 (E)63.18 Wrench feature torqueThe torque to be applied to the wrenching feature of the nut.4 Quality assurance4.1 QualificationEN 3042Qualification 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 simple 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 thedesign and manufacturing conditions are identical.Table 2 indicates the allocation of nut specimens for the inspections and tests.4.2 Acceptance4.2.1 PurposeThe purpose of acceptance inspections and tests is to check, as simply as possible, by a method representative ofactual use conditions, with the uncertainty inherent to statistical sampling, that the nuts constituting the batchsatisfy the requirements of this standard.4.2.2 ConditionsAcceptance inspections and tests (requirements, methods, numbers of nuts) are specified in table 1 ; they shall becarried out on each production batch or inspection lot. Nuts from the batch or lot to be tested shall be selected bysimple 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 beperformed during the acceptance inspection and testing. In this case, the number of nuts submitted to theseinspections and tests is the same as that submitted for qualification inspection and tests.4.2.3 ResponsibilityAcceptance inspections and tests shall be carried out by the manufacturer, or under his responsibility.4.2.4 Inspection and test reportA test report showing actual numerical values shall be provided if specified in the purchase order.SIST EN 3752:2004
EN 3752:2003 (E)75 RequirementsSee table 1.Table 1: Technical requirements and test methodsClauseCharacteristicRequirementInspection and test methodQ/A
Sample sizeQ5.1MaterialIn accordance with the productstandard or definition documentChemical analysis or certificate ofconformity issued by themanufacturer of the semi-finishedproductAQ465.2Dimensions,tolerances andtolerances of formand positionIn accordance with the productstandard or definition documentStandard gaugingATables 3 and 45.3ManufacturingQ5.3.1FormingNuts shall be formed by a hot orcold forming process.If hot formed, the formingtemperature shall not exceed 1150 °C and they shall be aircooled or faster.The equipment shall ensure auniform temperature throughoutthe production batch.The method of forming shall beindicated.Q5.3.2Heat treatmentThe heat treatment medium oratmosphere shall not cause anysurface contamination except aspermitted by 5.5.5.Any scale which will not beremoved by subsequentmachining shall be removed byabrasive blasting.Calibration of the heat treatmentequipment shall be confirmed.Appropriate equipment5.3.2.1Solution andprecipitation heattreatmentSolution treat (if applicable) at atemperature of 900 °C to 980 °C,held at the selected temperaturewithin ± 15 °C for between 1 hmin. and 2 h max., quench in oil,or alternative medium or faster.Precipitation treat at 720 °C + 10°C held at temperature for 16 h ±15 min cooled in air or faster.(continued)SIST EN 3752:2004
EN 3752:2003 (E)8Table 1 (continued)ClauseCharacteristicRequirementInspection and test methodQ/A 1)Sample sizeQ465.3.3Bearing surfaceperpendicularityIn accordance with the productstandard or definitiondocumentFor non-floating plate nutshaving a bearing surfaceexceeding 1,5 times the threadnominal diameter, theperpendicularity requirementshall, unless otherwisespecified by the productstandard or definitiondocument, apply only to th
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