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STANDARD
SIST EN 2002-005:2009
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 2002-005November 2007ICS 49.025.10 English VersionAerospace series - Test methods for metallic materials - Part005: Uninterrupted creep and stress-rupture testingSérie aérospatiale - Méthodes d'essais applicables auxmatériaux métalliques - Partie 005 : Essai non interrompude fluage et essai de rupture par fluageLuft- und Raumfahrt - Prüfverfahren für metallischeWerkstoffe - Teil 005: Kriech- und Zeitstandversuch unterkonstanter ZugbeanspruchungThis European Standard was approved by CEN on 23 June 2007.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 CEN 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 CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2007 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 2002-005:2007: ESIST EN 2002-005:2009
EN 2002-005:2007 (E) 2 Contents Page Foreword.3 1 Scope.4 2 Normative references.4 3 Principle.4 4 Terms and definitions.4 5 Symbols and abbreviations.7 6 Specification of test requirements.9 7 Testing equipment.9 8 Proportional test pieces.11 9 Non-proportional test pieces.13 10 Preparation of test piece from sample.13 11 Measurement of cross-sectional area.14 12 Marking the original gauge length.14 13 Heating of test piece.14 14 Temperature control and observations.14 15 Loading of the test piece.14 16 Stress rupture test.15 17 Creep strain test – Determination of total plastic strain.15 18 Test report.16
SIST EN 2002-005:2009
EN 2002-005:2007 (E) 3 Foreword This document (EN 2002-005:2007) has been prepared by the Aerospace and Defence Industries Association of Europe - Standardization (ASD-STAN). After enquiries and votes carried out in accordance with the rules of this Association, this Standard has received the approval of the National Associations and the Official Services of the member countries of ASD, prior to its presentation to CEN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by May 2008, and conflicting national standards shall be withdrawn at the latest by May 2008. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom.
SIST EN 2002-005:2009
EN 2002-005:2007 (E) 4 1 Scope This standard applies to uninterrupted constant-load tensile creep strain and stress-rupture testing of metallic materials governed by aerospace standards. It defines the properties that may need to be determined and the terms used in describing tests and test pieces. It specifies the dimensions of test pieces and the method of testing. The duration of the creep strain and stress-rupture tests complying with this standard shall be less than 10 000 h and at temperatures not exceeding 1 100 °C. This standard may also apply to metallic materials for test durations exceeding 10 000 h and/or for test temperatures exceeding 1 100 °C providing that previous agreement has been reached between the manufacturer and the purchaser. 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 the referenced document (including any amendments) applies. EN ISO 7500-1, Metallic materials — Verification of static uniaxial testing machines — Part 1: Tension/compression testing machines — Verification and calibration of the force-measuring system (ISO 7500-1:2004) EN ISO 9513, Metallic materials — Calibration of extensometers used in uniaxial testing (ISO 9513:1999) ASTM E 1012-91, Practice for verification of specimen alignment under tensile loading. 1) 3 Principle The test consists in maintaining a test piece at a uniform temperature and subjecting it to a constant tensile force at that temperature in order to determine specified properties. 4 Terms and definitions For the purposes of this document, the following terms and definitions apply. 4.1
test piece portion of the test sample on which the creep strain or stress-rupture test is carried out (see Figures 1 to 5) 4.2
proportional test piece these test pieces have an original basis gauge length (Lo = Leo' or Ls') which bears a specified relationship to the cross-sectional area This ensures that comparable values for percentage elongation after rupture (A) are obtained from test pieces of different size but having the same relationship. The relationship Lo = 5,65oS which for test pieces of circular cross section gives a value of Lo = 5 do has been accepted by international agreement and is preferred in the use of this standard. The relationship is indicated in the symbol for percentage elongation after rupture (A) as a subscript, e.g. A5' representing the ratio Lo/d.
1) Published by American Society for Testing and Materials (ASTM), 1916 Race Street, Philadelphia, PA 19103. SIST EN 2002-005:2009
EN 2002-005:2007 (E) 5 4.3
non-proportional test piece in cases where the original basis gauge length has not the defined relationship to the cross-sectional area, a subscript shall be used with the symbol for elongation A to indicate the gauge length, i.e. A40 mm 4.4
gauge length a length of the test piece on which elongation is measured at any moment during the test 4.5
measurement gauge length (Lm) the measurement gauge length shall be defined as either the extensometer gauge length Leo for test pieces measured with extensometers gripping the parallel portion of the specimen or small annular ridges, when these are used, or the shoulder gauge length Ls for test pieces where extension is measured between points including the transition radii and/or gripping portions of the test piece The measurement gauge length (Lm) is to be used only for the numerator in elongation calculations; that is, the change in length of that part of the test piece defined as Lm, whereas the basis gauge length, i.e. Leo' or Ls', is to be used for the denominator. 4.6
extensometer gauge length (Leo) where an extensometer is attached directly to the parallel portion of the unloaded test piece, the extensometer gauge length (Leo) is equal to the distance between the points of contact of the extensometer measured at room temperature, and shall also be used as the corresponding basis gauge length Alternatively, the extensometer may be attached to annular ridges on the parallel portion. In these cases, the basis gauge length to be used as the denominator in the elongation calculations shall be the equivalent gauge length, calculated as shown (see 4.7). 4.7
basis gauge length for elongation calculations (Leo' or Ls') the equivalent gauge length, i.e. the parallel length which would give the same extension, including all loaded portions of the test piece between the measuring points, except the gripped ends It shall be used as the denominator in all elongation calculations. For stress-rupture test pieces, it is recommended that Leo' or Ls' be calculated from the following equation: Leo' or Ls' = Lc + 2 []∑=×kiiioLdd12n)/( = 5,65oS where: Lc is the parallel length between the annular ridges or test piece ends, with a diameter do, k is the number of sections of length Li with increasing diameter of di at the two transition radii. The correct Lc shall be selected, so that the effective gauge length equals 5,65 oS. It is recommended to use n = 6 as a basis for comparison, although the actual n for many aerospace materials is > 6. This is based on the "power law" creep relationship: ε.p = nKσ 4.8
shoulder gauge length (Ls) where the extension is measured at the test piece ends, or between reference marks on the enlarged ends of the test piece, the shoulder gauge length (Ls) shall be denoted The basis gauge length shall be calculated as in 4.7 and based on room temperature measurements, including all loaded portions of the test piece between the measuring points, except the gripped ends. SIST EN 2002-005:2009
EN 2002-005:2007 (E) 6 4.9
parallel length (Lc) the length of the parallel portion of the test piece For some test pieces, Lc will be less than Lm, the applicable original gauge length. 4.10
extension (∆Le) the increase of the extensometer gauge length from the initial length, Leo or Leo', indicated at the test temperature before loading, to a value Le at a given moment during the test. 4.11
final measurement length after rupture (Lu) the measure of the applicable gauge length (Leu or Lsu) after the test piece has ruptured, measured at room temperature This may include the unstressed test piece ends, if the total length is used as the gauge length. 4.12
percentage elongation after rupture (A) the permanent increase in length (Lu – Lm) of the applicable measurement gauge length, expressed as a percentage of the original applicable basis gauge length (Leo' or Ls'), for example: A = eo'eo'uLLL− × 100, all measurements being made at room temperature 4.13
percentage extension during testing (Af) the increase of the applicable gauge length, at a given time under full load, expressed as a percentage of the original applicable gauge length The initial plastic strain during loading shall not be included in Af, just the elongation after attainment of full load (see Figure 6). 4.14
percentage total plastic strain (Ap) the total plastic extension of the original applicable measurement gauge length (Leo or Ls) inclusive of any plastic extensions during loading (i.e. the total extension excluding elastic extensions), expressed as a percentage of the original applicable basis gauge length (see Figures 6 and 7) 4.15
original section (So) the cross-sectional area of the gauge length of the test piece, determined before testing 4.16
final section (Su) the minimum cross-sectional area of the test piece, after rupture 4.17
percentage reduction of area after rupture (Z) the maximum decrease of the cross-sectional area (So – Su) expressed as a percentage of the original cross-sectional area (So), i.e. Z = ouoSSS−× 100 SIST EN 2002-005:2009
EN 2002-005:2007 (E) 7 4.18
stress (σ) the force on the test piece divided by the original cross-sectional area of the parallel portion It should be noted that the thermal expansion of the test piece during heating increases the effective cross-sectional area. The effective stress is therefore slightly less than σ, which is based on room temperature. 4.19
rupture complete fracture of the test piece within the original gauge length under constant force and at constant temperature 4.20
time to rupture (tr) the total time, at the test temperature and the test force, to the rupture of the test piece (see Figure 7) 4.21
time to specified total plastic strain (tp) the total time, at the test temperature and including the portion of the loading time after the loading curve deviates from an extension of the linear-elastic modulus line, until the specified total plastic strain (Ap) is reached (see Figure 6) 4.22
theoretical stress concentration factor (Kt) the ratio of the greatest in the region of a notch as determined by the theory of elasticity to the corresponding nominal stress Kt = nom.peakσσ where Kt is the theoretical stress concentration factor; σpeak is the peak stress by notch; σnom. is the nominal stress. 5 Symbols and abbreviations See Table 1 and Figures 1 to 5. SIST EN 2002-005:2009
EN 2002-005:2007 (E) 8 Table 1 Symbol Unit Designation a mm Thickness of test section of test piece of rectangular cross-section A % Percentage elongation after rupture Af % Percentage strain during testing Ap % Percentage total plastic strain α ° Notch angle b mm Width of test section of test piece of rectangular cross-section d mm Diameter of test section of test piece of circular cross-section dn mm Diameter of test piece at root of notch Dn mm Diameter of the parallel portion of a notched test piece of circular cross-section Kt – Theoretical stress concentration factor of a notched test piece Lc mm Parallel length Le mm Extensometer gauge length (Leo = initial ; Leu = final) Lo, Leo' or Ls' mm Basis gauge length for elongation calculations ∆Le mm Extension of extensometer gauge length Lm mm Measurement gauge length Ln mm Parallel length of the test piece containing the notch Ls mm Shoulder gauge length for test without extensometer on the parallel length
(Lso = initial; Lsu = final) Lt mm Total length of the test piece Lu mm Final measurement length after rupture r mm Transition radius rn mm Notch root radius δ MPa Stress, based on room temperature cross-sectional area So mm2 Original room temperature cross-sectional area of test section Su mm2 Minimum cross-sectional area of test section after rupture t h Time of the test under specified conditions for temperature and stress tp h Time to specified total plastic strain tr h Time to rupture θT °C Test temperature Z % Percentage reduction of area after rupture
SIST EN 2002-005:2009
EN 2002-005:2007 (E) 9 6 Specification of test requirements The material standard shall state the following: type of test piece (see Clauses 8 and 9); specified test temperature (θT); specified test stress (σ); time the test piece shall be simultaneously under the specified conditions of temperature and stress (t); maximum soaking time where applicable (see Clause 13); criterion of acceptance which may be one of the following: a) a statement of the percentage total plastic strain (Ap) or percentage total strain (Af) that shall not be exceeded; b) a requirement that the test piece shall not rupture before the end of the test time specified above; c) any other requirement specified, such as minimum percent elongation at fracture. 7 Testing equipment
7.1 Load calibration The testing machine shall be calibrated at intervals not exceeding one year in accordance with EN ISO 7500-1 and shall be at grade 1,0 or better. The machine should be equipped with a device which minimizes shock when the test piece ruptures (only with more than 1 test device). 7.2 Strain calibration The instruments used for the measurements of creep strain shall have an accuracy within 0,006 % of the gauge length or 1 % of the total creep strain to be measured, whichever is the greater. They shall be calibrated at intervals not exceeding one year in accordance with EN ISO 9513, class 0.5. Calibration should be checked at more frequent. More frequent spot checks are recommended. 7.3 Calibration for long-term tests Where long-term tests are carried out in excess of one year the testing machine and extensometer shall be calibrated immediately before and on the completion of such tests. 7.4 Extensometer requirements If an extensometer is used, it shall be capable of measuring the extension on opposite sides of the test piece, and the readings shall be averaged. An extensometer that measures the extension on each side and gives only the average reading, or measures only one length may be used by agreement between the manufacturer and the purchaser of the material being tested. Any parts of the extensometer projecting beyond the furnace shall be so designed or protected that short period changes of temperature or draughts do not affect readings. It is advisable to maintain reasonable stability of the temperature of the air surrounding the testing machine. A temperature-compensated extensometer is recommended. 7.5 Machine alignment Test pieces shall be held by a positive means, in such a way that the load can be applied as axially as possible. If bending is not measured as in 17a), then the machine grips shall be checked on at least an annual basis with a strain-gauged test piece at room temperature. The difference between strains on any two opposing sides of the test piece shall not be more than 10 % of the mean strain, at the lowest force used on the machine during tests. The ASTM E 1012 may be referred to for a verification method. SIST EN 2002-005:2009
EN 2002-005:2007 (E) 10 7.6 Measurement of temperature Temperature measuring equipment with a sensibility of at least 1 °C shall be used to ensure tha
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