Aerospace series - Metallic materials - Test methods - Constant amplitude fatigue testing

This European Standard defines a method to determine constant amplitude fatigue data of metallic materials and the S-N curve (or Wöhler curve).

Luft- und Raumfahrt - Metallische Werkstoffe - Prüfverfahren - Ermüdungstest mit konstanter Amplitude

Diese Europäische Norm legt ein Verfahren zur Bestimmung der Daten aus dem Ermüdungsversuch mit
konstanter Amplitude für metallische Werkstoffe und zur Erstellung der S-N-Kurve (oder Wöhlerkurve) fest.

Série aérospatiale - Matériaux métalliques - Méthodes d’essai - Essai de fatigue à amplitude constante

Cette Norme européenne définit une méthode destinée à déterminer les données relatives aux essais de fatigue à amplitude constante des matériaux métalliques et la courbe S-N (ou courbe de Wöhler).

Aeronavtika - Kovinski materiali - Preskusne metode - Preskus utrujanja z nespremenljivo amplitudo

Ta evropski standard določa metodo za določevanje podatkov utrujanja z nespremenljivo amplitudo kovinskih materialov in J-S krivulje (ali Wöhlerjeve krivulje).

General Information

Status
Published
Publication Date
12-Jul-2010
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
01-Jul-2010
Due Date
05-Sep-2010
Completion Date
13-Jul-2010

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SLOVENSKI STANDARD
SIST EN 6072:2010
01-september-2010
Aeronavtika - Kovinski materiali - Preskusne metode - Preskus utrujanja z
nespremenljivo amplitudo

Aerospace series - Metallic materials - Test methods - Constant amplitude fatigue testing

Luft- und Raumfahrt - Metallische Werkstoffe - Prüfverfahren - Ermüdungstest mit
konstanter Amplitude

Série aérospatiale - Matériaux métalliques - Méthodes d’essai - Essai de fatigue à

amplitude constante
Ta slovenski standard je istoveten z: EN 6072:2010
ICS:
49.025.05 Železove zlitine na splošno Ferrous alloys in general
SIST EN 6072:2010 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 6072:2010
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SIST EN 6072:2010
EUROPEAN STANDARD
EN 6072
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2010
ICS 49.025.05
English Version
Aerospace series - Metallic materials - Test methods - Constant
amplitude fatigue testing

Série aérospatiale - Matériaux métalliques - Méthodes Luft- und Raumfahrt - Metallische Werkstoffe -

d'essai - Essai de fatigue à amplitude constante Prüfverfahren - Ermüdungstest mit konstanter Amplitude

This European Standard was approved by CEN on 25 December 2009.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European

Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national

standards 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 translation

under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the

official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, 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 STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels

© 2010 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 6072:2010: E

worldwide for CEN national Members.
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SIST EN 6072:2010
EN 6072:2010 (E)
Contents Page

Foreword ..............................................................................................................................................................3

1 Scope ......................................................................................................................................................4

2 Normative references ............................................................................................................................4

3 Terms and definitions ...........................................................................................................................4

4 Principles of the method .......................................................................................................................5

5 Apparatus ...............................................................................................................................................5

6 Test specimens ......................................................................................................................................5

7 Procedure ...............................................................................................................................................6

8 Analysis of test results .........................................................................................................................7

9 Test report ..............................................................................................................................................7

Annex A (normative) Axial Fatigue - Cylindrical specimen ......................................................................... 13

Annex B (normative) Axial Fatigue - Flat specimen (K ==== 1,0) ...................................................................... 17

Annex C (normative) Axial Fatigue - Flat specimen - "T-Type" and mini "T-Type" specimen

(K ==== 2,3) ............................................................................................................................................... 19

Annex D (normative) Bending Fatigue - Flat specimen ............................................................................... 21

Annex E (normative) Recommendations for machining procedure of specimen ..................................... 23

E.1 Cylindrical specimens ........................................................................................................................ 23

E.2 Flat specimens .................................................................................................................................... 26

Annex F (normative) Indication of failure sites ............................................................................................. 29

Annex G (normative) Table of fatigue test results ........................................................................................ 30

Annex H (normative) Representation of fatigue data ................................................................................... 31

Annex I (informative) Example of inspection card process ......................................................................... 32

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SIST EN 6072:2010
EN 6072:2010 (E)
Foreword

This document (EN 6072:2010) 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 December 2010, and conflicting national standards shall be withdrawn

at the latest by December 2010.

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, Croatia, 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.
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SIST EN 6072:2010
EN 6072:2010 (E)
1 Scope

This European Standard defines a method to determine constant amplitude fatigue data of metallic materials

and the S-N curve (or Wöhler curve).
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.

ISO 286-1, ISO system of limits and fits — Part 1: Bases of tolerances, deviations and fits

ISO 965-1, ISO general-purpose metric screw threads — Tolerances — Part 1: Principles and basic data

ISO 1101, Geometrical Product Specifications (GPS) — Geometrical tolerancing — Tolerances of form,

orientation, location and run-out

ASTM E 466, Standard practice for conducting force controlled constant amplitude axial fatigue tests of

1)
metallic materials
ASTM E 1823, Standard terminology relating to fatigue and fracture testing
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ASTM E 1823 and the following apply.

3.1 Direction of test samples
3.1.2
cylindrical specimens
the direction of the sample is identified by the following symbols:
L : Long (grain flow direction);
LT : Long Transverse;
ST : Short Transverse.

The directions of semi-finished products of rectangular cross section for rolled or extruded products and

forgings are identified on Figure 1.

The directions of semi-finished products of circular cross section for rolled products and forged rings are

identified on Figure 2.
3.1.2
flat specimens
designation for direction of these specimens is identical to ASTM designation:
Two letters separated by a dash:
First letter : direction of load
Second letter : direction of crack propagation

The directions of semi-finished products of rectangular cross section for rolled or extruded products and hand

forgings are identified on Figure 3.

Published by: American Society for Testing and Materials (ASTM), 1916 Race Street, Philadelphia, PA 19103, USA.

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SIST EN 6072:2010
EN 6072:2010 (E)

The directions of semi-finished products of circular cross section for drawn or extruded products and hand

forgings are identified on Figure 4.
4 Principles of the method
See ASTM E 466.
5 Apparatus
See ASTM E 466 (calibrating to ISO 7500-1 is also acceptable).
6 Test specimens
6.1 General

Test specimens shall be prepared according to the requirements of the relevant Process or Material Standard.

6.2 Geometry
The geometry of test specimens is described in Annexes A to D.
6.3 Machining
6.3.1 Dimensional tolerances

Machining tolerances (according to ISO 286-1) on transverse dimensions: ISO js 12.

Form tolerances (according to ISO 1101) = ISO IT9.

Specimens shall be machined cold, without generating surface hardening nor appreciable heating of the metal.

Recommendations for machining procedure of specimens are given in Annex E for each type of specimen.

Final machining to comply with the tolerances and to obtain the surface finish required on the calibrated

section (see Annexes A to D).
6.3.2 Specimens to be heat-treated

The heat treatment should preferably be applied to the specimen blanks to avoid distortion, which cannot be

corrected by machining.
Final machining after heat treatment, in accordance with 6.3.1.

NOTE For steels treated to obtain a high UTS, it may be necessary to machine the specimens to the final dimensions

in the as-delivered condition and then protect them before heat treatment.
In general, the surface of steel and aluminium alloys specimens shall be:
— either protected against corrosion by an appropriate product,
— or machined only shortly before carrying out the test.
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SIST EN 6072:2010
EN 6072:2010 (E)
6.3.3 Grinding

Grinding of steel and titanium specimens shall only be carried out when a process is available which

guarantees no detrimental effects to the specimen surface, for example contamination.

6.4 Straightening
It is strictly forbidden to straighten a distorted specimen.

Such distortion can arise from heat treatment on specimens machined to their final dimensions.

The surface hardening generated by the mechanical equipment used to straighten the specimens affects the

mechanical properties and gives unrepresentative results.
7 Procedure
7.1 Number of specimens

A minimum of 10 fatigue specimens with valid results is necessary to determine a Wöhler curve.

Upon request, a static loaded specimen shall be performed.
7.2 Measurements of specimen dimensions

The dimensions of the test specimens shall be measured before testing and the results reported in the test

report (see Clause 9).
7.3 Test procedure

Load ratio R and K factor are given in the relevant Process or Material Standard.

The test frequency shall be not more than 170 Hz. For frequency greater than 50 Hz, it is advisable to carry

dynamic calibrations on test work.

The choice of load levels shall be done in order that test results can be regularly positioned on the S-N curve

4 6

between at least 10 and 3.10 cycles, so that a Wöhler curve can be raised. For qualification of materials,

cycling must not be stopped before 3.10 cycles, unless other conditions are specified. In case of non-failure

at 3.10 cycles (or more), specimen can be tested again at a higher load level that will lead to failure before

10 cycles. Test results must mention that specimen has been tested after a non-failure so that analysis can

take it into account.
NOTE For load ratio R < 0, it is recommended to use anti buckling equipment.

The breaking near the grip and the associated number of cycles shall be mentioned in the test report (see

Clause 9). In this case the specimen should be clamped again (if possible) and the test should be continued at

the same load level.

In order to check the reproducibility and friability of test machine, an example of inspection card is given in

Annex I.
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SIST EN 6072:2010
EN 6072:2010 (E)
8 Analysis of test results
8.1 Failure of specimens

After testing, specimens shall be examined. Failure type and sites shall be indicated (see Annex F).

8.2 Presentation of fatigue data

All the values measured and calculated from the specimens shall be reported in a table (see Annex G).

The cross section of the specimen, which has been used for calculation, shall be indicated.

8.3 Plot of the Wöhler curve

All the individual results shall be represented in a log (or semi-log) scale scheme: max. stress in MPa, σ,

versus Fatigue life, number of cycles, N (see Annex H).

The analysis of the test results shall generate a mean Wöhler curve with 50 % probability of failure, in addition

two curves for minimum and for maximum probability of failure.
9 Test report
The test report shall refer to the test method and shall include the following:

 Complete identification of the tested material including the manufacturers Name, Designation, and Batch

Number.
 All details relating to the preparation of the specimens.
 All relevant dimensions of the specimens.
 Date of test and traceability to the individual performing the test work.
 Conditioning.
 Equipment used and test parameters (R ratio, test frequency, orientation ...).
 Recorded plots/graphs (with all the points).
 Individual test results and type of failure (see Annex F and Annex G).

 Any incident which may have affected the results, and any deviation from the test method.

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SIST EN 6072:2010
EN 6072:2010 (E)
Key
L : Long (grain flow direction)
LT : Long Transverse
ST : Short Transverse

Figure 1 — Cylindrical specimens - Direction of semi-finished products of rectangular cross section

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SIST EN 6072:2010
EN 6072:2010 (E)
Key
1 Axial: corresponds to LT direction
2 Radial: corresponds to ST direction
3 Tangential: corresponds to L direction (grain flow direction)
Depending on the forging axis, the LT and ST directions can change.

Figure 2 — Cylindrical specimens - Direction of semi-finished products of circular cross section

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SIST EN 6072:2010
EN 6072:2010 (E)
Key
L : Long (grain flow direction)
LT : Long Transverse
ST : Short Transverse
Two letters separated by a dash:
First letter : direction of load
Second letter : direction of crack propagation

Figure 3 — Flat specimens - Direction of semi-finished products of rectangular cross section

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SIST EN 6072:2010
EN 6072:2010 (E)
Key
L: direction of grain flow
R: radial direction
C: circumferential direction

Figure 4 — Flat specimens - Direction of semi-finished products of circular cross section

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SIST EN 6072:2010
EN 6072:2010 (E)
Figure 5 — Tool for chamfering
(can be ordered from Recoules Society or from Rexim Werkzeug GmbH)
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SIST EN 6072:2010
EN 6072:2010 (E)
Annex A
(normative)
Axial Fatigue - Cyl
...

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