Aerospace series - Pipe coupling 8°30' up to 28 000 kPa - Dynamic beam seal - Metric series - Technical specification

This standard specifies the required characteristics, inspection and test methods, quality assurance and procurement
requirements for metric series 8 30' dynamic beam seal pipe couplings, for temperature ranges type II and III according
to ISO 6771 and nominal pressure up to 28 000 kPa.

Luft- und Raumfahrt - Rohrverschraubung 8°30' bis 28 000 kPa - Dichtlippe - Metrische Reihe - Technische Lieferbedingungen

Série aérospatiale - Système de raccordement 8°30' jusqu'à 28 000 kPa - Joint à lèvre - Série métrique - Spécification technique

Aerospace series - Pipe coupling 8°30' up to 28 000 kPa - Dynamic beam seal - Metric series - Technical specification

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EN 3275:2004
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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Aerospace series - Pipe coupling 8°30' up to 28 000 kPa - Dynamic beam seal - Metric series - Technical specificationLuft- und Raumfahrt - Rohrverschraubung 8°30' bis 28 000 kPa - Dichtlippe - Metrische Reihe - Technische LieferbedingungenSérie aérospatiale - Systeme de raccordement 8°30' jusqu'a 28 000 kPa - Joint a levre - Série métrique - Spécification techniqueAerospace series - Pipe coupling 8°30' up to 28 000 kPa - Dynamic beam seal - Metric series - Technical specification49.080Aerospace fluid systems and componentsICS:Ta slovenski standard je istoveten z:EN 3275:2002SIST EN 3275:2004en01-maj-2004SIST EN 3275:2004SLOVENSKI

SIST EN 3275:2004

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EN 3275:2002 (E)ContentsForeword31
Normative references43
Terms and definitions55
Requirements, inspection and test methods76
Quality assurance217
Preparation for delivery22Annex A (normative)
Production batch identification272SIST EN 3275:2004

EN 3275:2002 (E)ForewordThis document (EN 3275:2002) has been prepared by the European Association of Aerospace Manufacturers(AECMA).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 toits presentation to CEN.This European Standard shall be given the status of a national standard, either by publication of an identical textor by endorsement, at the latest by October 2002, and conflicting national standards shall be withdrawn at thelatest by October 2002.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, Iceland, Ireland, Italy Luxembourg, Malta, Netherlands, Norway, Portugal, Spain,Sweden, Switzerland and United Kingdom.3SIST EN 3275:2004

EN 3275:2002 (E)1
ScopeII and III accordingto ISO 6771 and nominal pressure up to 28 000 kPa.2

Normative referencesThis European Standard incorporates by dated or undated reference provisions from other publications. Thesenormative references are cited at the appropriate places in the text and the publications are listed hereafter. Fordated references, subsequent amendments to or revisions of any of these publications apply to this EuropeanStandard only when incorporated in it by amendment or revision. For undated references, the latest edition of thepublication referred to applies (including amendments).ISO 468,

Surface roughness — Parameters, their values and general rules for specifying requirements.ISO 2685,

Aircraft — Environmental test procedure for airborne equipment — Resistance to fire in designated firezones.ISO 2859-1,

Sampling procedures for inspection by attributes — Part 1: Sampling schemes indexed by acceptancequality limit (AQL) for lot-by-lot-inspection.ISO 6771,

Aerospace — Fluid systems and components — Pressure and temperature classifications.ISO 6772,

Aerospace — Fluid systems — Impulse testing of hydraulic hose, tubing and fitting assemblies.ISO 7137,

Aircraft — Environmental conditions and test procedures for airborne equipment.ISO 7257,

Aircraft — Hydraulic tubing joints and fittings — Rotary flexure test.ISO 8625-1,

Aerospace — Fluid systems — Vocabulary — Part 1: General terms and definitions relating topressure.ISO 9538,

Aerospace — Hydraulic tubing joints and fittings — Planar flexure test.EN 2813,

Aerospace series — Aluminium alloy AL-P6061-T6 — Drawn tube for pressure applications - 0,6 mm £a £ 12,5 mm.1)EN 3042,

Aerospace series — Quality assurance — EN aerospace products — Qualification procedure.EN 3120,

Aerospace series — Titanium alloy TI-P64003 — Cold worked and stress relieved — Seamless tube forpressure systems — 4 mm £ D £ 51 mm -690 MPa

1 030 MPa.1)EN 10204,
Metallic products — Types of inspection documents.TR 2674,

Aerospace series — Design and construction of pipelines for fluids in liquid or gaseous condition — Rigidlines, installation.2)MIL-H-5606,

Hydraulic fluid, Petroleum Base, Aircraft, Missile and Ordnance.3)MIL-H-8446,
Hydraulic fluid, Nonpetroleum Base, Aircraft.3)
1) Published as AECMA Prestandard at the date of publication of this standard

2) Published as AECMA Technical Report at the date of publication of this standard

3) Published by: Department of Defense (DoD), the Pentagon, Washington, D.C. 20301.4SIST EN 3275:2004

EN 3275:2002 (E)3

SymbolsAElongation, in percentD0Actual outside diameter of pipe, in millimetresD1Actual inside diameter of pipe, in millimetresDNNominal outside diameter of pipePWorking pressure, in megapascalsRmTensile strength, in megapascalsRp0,20,2 % proof stress, in megapascalssxAxial stress due to pressure, in megapascals4

Terms and definitionsFor the purposes of this standard, the following terms and definitions apply:4.1

PressureNominal pressure, proof pressure, impulse pressure, burst pressure according to ISO 8625-1.4.2

Coupling4.2.1Coupling assemblyassembled and torque-tightened nut, ferrule and pipe mating with e.g. unions, tees or elbows (See figure 1)Key1Dynamic beam seal2Ferrule3Nut4Union endFigure 1 — Example of coupling assembly4.2.2Straight couplingunion connecting pipe to pipe5SIST EN 3275:2004

EN 3275:2002 (E)4.2.3Forged parts; shaped partscouplings machined out of individual forging blanks. For crosses, tees and elbows machined out of bar or plate stockthe term "shaped" may be used4.3

Surface defects4.3.1Surface irregularitynonconformity with general surface appearance, possible defect4.3.2Crackclean (crystalline) fracture passing through or across the grain boundaries that possibly follows inclusions of foreignelements. Cracks are normally caused by overstressing the metal during forging or other forming operations, orduring heat treatment. Where parts are subject to significant reheating, cracks are usually discoloured by scale4.3.3Folddoubling over of metal, which can occur during the forging operation. Folds can occur at or near the intersection ofdiameter changes and are especially prevalent with non-circular necks, shoulders and heads4.3.4Lapfold-like machining defect4.3.5Seam(1)usually a surface opening or crack resulting from a defect obtained during casting or forging(2)extraneous material, stringer in the material, which is not homogeneous with base metal4.3.6Pitvoid or hole in the surface as caused, for example, by corrosion4.4

Quality assurance4.4.1Production batcha definite quantity of some commodity or service produced at one time under conditions that are presumed uniform4.4.2Delivery batchbatch consisting of couplings with the same identity block which may come from different production batches.4.4.3Acceptable quality level (AQL)when a continuing series of lots is considered, a quality level which for the purposes of sampling inspection is thelimit of a satisfactory process average6SIST EN 3275:2004

EN 3275:2002 (E)4.4.4Qualificationtesting required to demonstrate successful performance of the coupling assembly in simulated service (overload,destructive and fatigue tests)4.4.5Major 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 purpose4.4.6Minor defecta defect that is not likely to reduce materially the usability of the considered product for its intended purpose, or thatis a departure from established specification having little bearing on the effective use or operation of this product5

Requirements, inspection and test methodsSee table 1 and table 2.5.1

Test conditions and preparation of specimens for qualificationTests fluids. Unless otherwise specified, tests shall be carried out using e.g. a petroleum base hydraulic fluid toMIL-H-5606 for coupling assemblies of type II temperature range and a silicate ester base hydraulic fluid toMIL-H-8446 for those of type III temperature range. Water may be used, whenever practical, for proof, burst, stresscorrosion and re-use capability testing. For other than hydraulic system applications, it is preferable to use systemfluid for leakage (gaseous pressure) and proof testing. When specified in the test method, the test fluid is used asa lubricant.Specimen preparation. Shaped parts shall be machined with the grain flow of the bar or plate in the direction ofthe fluid. Specimens shall be assembled as illustrated in table 2. Installations on the pipe end shall be in accordancewith TR 2674. Prior to testing, all couplings shall be assembled using the maximum specified torque. Except, whenspecified in table 2, the coupling shall be assembled using the minimum installation torque for at least half of thespecimens, and maximum torques for the remainder.Pipe assembly. The method of joining the pipe to the coupling end (brazing, welding, mechanical attachment, etc.)shall not be detrimental to the properties, strength or geometry of the pipe and the coupling end. The joint shall bein accordance with the design instructions and shall be inspected by direct measurement, X-ray or other non-destructive methods.7SIST EN 3275:2004

EN 3275:2002 (E)Table 1 — Requirements, inspection and test methodsClauseCharacteristicRequirementInspection and test methodQaAa5.2bMaterialsConformity with the productstandardsChemical analysis or certificate ofcompliance to EN 10204 issued bythe semi-finished productmanufacturer.X100 %X100 %5.3bDimensionsFluid passagesConformity with the productstandardsConformity with the productstandardsSuitable measuring instrumentsA ball with a diameter 0,5 mm lessthan the minimum diameter speci-fied for the passage shall passthrough the coupling.X100 %X100 %X50 %X20 %5.4bProductidentificationMarking according toproduct standards anddefinition documentsincluding batch identificationof Annex A. It shall belegible and shall notadversely affect the materialor the functioning of theproducts.Visual examinationX100 %X100 %5.5bSurfaceroughnessConformity with the productstandardsInterpreted in accordancewith ISO 468Suitable measuring instruments orvisual-tactile samplesX100 %X100 %5.6bSurfacetreatmentConformity with the productstandardsVisual examinationThe thread shall be tested using agauge with a tolerance class of4h6h.X100 %X100 %5.7bSurface defectsThreadsParts shall be free fromsurface defects indicated in4.3 liable to have anadverse affect on their cha-racteristics and endurance.Threads may be cut, rolledor ground, except titaniumalloys which shall be cut orrolled. The external threadsof couplings should berolled and, if machined,shall have an arithmeticalmean deviation, Ra, of theprofile of 3,2 µm orsmoother in accordancewith ISO 468.The grain flow in rolledthreads shall be continuousand follow the generalthread contour with themaximum density at thethread root. Visual inspection using suitable me-thodsVisual examinationThread flanks in rolled threads shallbe examined by micro-examination.Specimens shall be taken from thefinished part by sectioning on alongitudinal plane across thethreaded area. The specimens shallbe polished and etched to revealthe surface defects.X100 %X100 %X10 %X100 %X100 %X5 %8SIST EN 3275:2004

EN 3275:2002 (E)Table 1 (continued)ClauseCharacteristicRequirementInspection and test methodQaAa5.7(con-tinued)Laps, cracks, surfaceirregularities and seams(see 4.3) are notacceptable on any part ofthe pressure thread flank, inthe thread root or on thenon-pressure thread flank.Laps and seams, depths ofwhich are within the limitsof table, are acceptable onthe crest and the non-pressure thread flank abovethe pitch diameter.DNDepthmm050608101214 to 320,150,180,180,200,230,255.8Proof pressureThe coupling assemblyshall withstand a pressureequal to twice the nominalpressure of the fluid systemfor 5 min at ambienttemperature withoutleakage and shall not showany evidence of permanentdeformation or other mal-function when using thespecified torque values.The coupling assembly shall beconnected to a pressure sourcewith one end free to move. Rate of pressure increase shall be(150 000 ± 37 500 )kPa/min.X5.9GaseouspressureThe coupling assemblyshall withstand a gaseouspressure equal to thenominal pressure for 5 min,at ambient temperature.There shall be no visibleformation of bubbles after1 min at pressure or othermalfunction that wouldaffect assembly ordisassembly when using thetorque values specified.The coupling assembly shall besolvent cleaned and air dried priorto testing. It shall be assembled andtightened to the minimum torquesspecified in table 3. It shall then bepressurized with nitrogen to thenominal pressure. This pressureshall be maintained for 5 min whilethe specimens are immersed inwater or suitable oil (see figure 2).X9SIST EN 3275:2004

EN 3275:2002 (E)Table 1 (continued)ClauseCharacteristicRequirementInspection and test methodQaAa5.10HydraulicimpulseresistanceThe coupling assemblyshall withstand 200 000impulse pressure cycleswithout leakage.The coupling assembly shall beimpulse tested at the temperaturesand in the sequence specified inISO 6772.X5.11Minimum burstpressureThe coupling assemblyshall withstand a pressureequal to four times thenominal pressure of thefluid system for 5 min, when tested at ambienttemperature.There shall be no leakageor burst.Pipe expansion ispermissible. The couplingassemblies need not meetany disassembly orassemblies requirementsafter this test.The coupling assembly shall beconnected to a pressure sourcewith one end free to move. Rate of pressure increase shall be(150 000 ± 37 500) kPa/min.X5.12Flexure fatigueresistanceCoupling assembly weldedto pipes shall achieve atarget minimum flexurefatigue stress of 130 MPafor 107 cycles.For other methods ofjoining the coupling to thepipe the minimum flexurefatigue levels for eachDN size shall be as shownin table 4a or 4b.In accordance with either ISO 7257or ISO 9538. The bending stressshall be determined prior to theapplication of internal pressure.In order to obtain the true bendingstress, it is always necessary tomeasure the strain dynamically atthe flexure test frequency. Thetolerance for the specified bendingstress shall be from 0% to 10%.NOTE

If it is desired to express thestress in terms of combined pressureand bending stress, the axial pressurestress is calculated by the formula:X10SIST EN 3275:2004

EN 3275:2002 (E)Table 1 (continued)ClauseCharacteristicRequirementInspection and test methodQaAa5.12(con-tinued)Specimens according to figure3 shall pass this test withoutleakage from the couplingassembly or the pipe/couplinginterface. Recorded S/N curves shallshow characteristics equal toor greater than those of figure4.Thrustwire coupling assembliesshall achieve the flexurefatigue stress of 130 MPa for107 cycles, measured at thepipe/ coupling P×

D21D20 D215.13Stress corrosionresistanceThe coupling assembly shallwithstand salt spray exposurewithout any of the followingdefects:a) Indications of cracking orpitting of the exposed surfaceswhen visually examined at 10times magnification.b) Indications of inter- ortransgranular corrosive attackduring metallurgicalexamination of longitudinal andtransverse sections of thecoupling assembly.The coupling assembly shall be installedin a test apparatus (see figure 5) whichimposes a bending stress level equal to(85 ± 5) % of Rp0,2 of the pipematerial at the beam seal interface.Internal pressure equal to thenominal pressure of the hydraulicsystem shall be applied withoutremoving the bending stress. Thecoupling assembly shall then besubjected to the salt spray test inaccordance with ISO 7137.After exposure, the couplingassembly shall be subjected to theminimum burst pressure test. Thecoupling assembly shall then becleaned and subjected to micro-examination by sectioning.X11SIST EN 3275:2004

EN 3275:2002 (E)Table 1 (continued)ClauseCharacteristicRequirementInspection and test methodQaAa5.14Re-usecapabilityThe coupling assemblyshall withstand 25 repeatedassemblies, without any ofthe following defects:a) leakage at any of theproof pressure tests. b) Inability to tighten thecoupling by hand;c) nut deformationd) excessive galling ordamage to any surfaces ofthe coupling assemblywhich prevents thespecified tightening torquesfrom being appliedsmoothly;e) gaseous leakage afterthe final tighteningoperation.The torque to damage shallalso be determined and thevalues recorded. Forcouplings in titanium alloy itshall not be less thantwo times the maximumtorque, according to table 3up to DN 18 or 202 N m starting from DN 20. Forother materials values to bespecified.Damage is defined as oneor more of the followingdefects:a) distortion or cracking oft


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