EN 16602-70-37:2014

SLOVENSKI STANDARD
01-januar-2015
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Space product assurance - Determination of the susceptibility of metals to stress-
corrosion cracking
Raumfahrtproduktsicherung - Bestimmung der Anfälligkeit von Metallen für
Spannungsrisskorrosion
Assurance produit des projets spatiaux - Détermination de la susceptibilité des métaux à
la fissuration par corrosion sous contrainte
Ta slovenski standard je istoveten z: EN 16602-70-37:2014
ICS:
49.140 Vesoljski sistemi in operacije Space systems and
operations
77.060 Korozija kovin Corrosion of metals
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 16602-70-37
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2014
ICS 49.025.01; 49.140
English version
Space product assurance - Determination of the susceptibility of
metals to stress-corrosion cracking
Assurance produit des projets spatiaux - Détermination de Raumfahrtproduktsicherung - Bestimmung der Anfälligkeit
la susceptibilité des métaux à la fissuration par corrosion von Metallen für Spannungsrisskorrosion
sous contrainte
This European Standard was approved by CEN on 25 October 2014.

CEN and CENELEC 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-CENELEC Management Centre or to any CEN and CENELEC
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 and CENELEC member into its own language and notified to the CEN-CENELEC Management Centre
has the same status as the official versions.

CEN and CENELEC members are the national standards bodies and national electrotechnical committees of Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia,
Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.

CEN-CENELEC Management Centre:
Avenue Marnix 17, B-1000 Brussels
© 2014 CEN/CENELEC All rights of exploitation in any form and by any means reserved Ref. No. EN 16602-70-37:2014 E
worldwide for CEN national Members and for CENELEC
Members.
Table of contents
Foreword . 5
1 Scope . 6
2 Normative references . 7
3 Terms, definitions and abbreviated terms . 9
3.1 Terms defined in other standards . 9
3.2 Terms specific to the present standard . 9
3.3 Abbreviated terms. 10
3.4 Symbols . 11
4 Principles . 12
4.1 Overview . 12
4.2 Tensile test . 12
4.3 Fracture toughness test . 12
4.3.1 Overview . 12
4.3.2 Determination of fracture toughness using the K test method . 12
Ic
4.3.3 Determination of fracture toughness using the J test method . 13
Ic
4.3.4 Characterization of fracture toughness using the R-curve test method . 13
4.3.5 Characterization of fracture toughness using the CTOD test method . 13
4.4 Fatigue test . 14
4.4.1 General . 14
4.4.2 Force controlled constant amplitude axial fatigue test . 14
4.4.3 Strain-controlled fatigue test . 14
4.5 Fatigue crack propagation test . 14
4.5.1 Stable crack growth rate. 14
4.5.2 Crack propagation threshold . 15
4.6 Fracture and fatigue test in special environment . 15
4.7 Stress corrosion cracking test . 15
4.7.1 Overview . 15
4.7.2 Stress corrosion cracking test using smooth specimens . 15
4.7.3 Stress corrosion cracking test using pre-cracked specimens . 16
4.8 Creep test . 16
4.9 Test results presentation. 16
5 Requirements . 17
5.1 Customer agreement . 17
5.2 Tensile testing . 17
5.2.1 General . 17
5.2.2 Tensile testing of weldments . 17
5.3 Fracture toughness test . 18
5.3.1 K test method . 18
Ic
5.3.2 J test method . 18
Ic
5.3.3 R-curve test method . 18
5.3.4 CTOD test method . 18
5.4 Fatigue test . 19
5.4.1 Force controlled constant amplitude axial fatigue test . 19
5.4.2 Strain-controlled fatigue test . 19
5.5 Fatigue crack propagation test . 20
5.5.1 Determination of fatigue crack growth rate . 20
5.5.2 Determination of a fatigue crack propagation threshold . 20
5.6 Fracture and fatigue tests in special environments . 21
5.7 Stress corrosion cracking test . 21
5.7.1 Stress corrosion cracking test using smooth specimens . 21
5.7.2 Stress corrosion cracking test using pre-cracked specimens . 21
5.8 Creep test . 21
5.9 Evaluation of test results . 21
5.10 Storage . 22
5.11 Reporting . 22
5.12 Quality assurance . 22
5.12.1 General . 22
5.12.2 Calibration . 22
5.12.3 Quality control of raw materials . 23
5.12.4 Nonconformance . 23
5.12.5 Traceability and records . 23
Annex A (normative) Request for mechanical testing of materials – DRD . 24
Annex B (normative) Proposal for mechanical testing of materials – DRD . 26
Annex C (normative) Report of mechanical testing of materials – DRD . 28
Annex D (informative) References . 31
Bibliography . 32

Foreword
This document (EN 16602-70-37:2014) has been prepared by Technical
Committee CEN/CLC/TC 5 “Space”, the secretariat of which is held by DIN.
This standard (EN 16602-70-37:2014) originates from ECSS-Q-ST-70-45C.
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 April 2015,
and conflicting national standards shall be withdrawn at the latest by April
2015.
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.
This document has been prepared under a mandate given to CEN by the
European Commission and the European Free Trade Association
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, Former Yugoslav Republic of Macedonia, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,
Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United
Kingdom.
Scope
This Standard specifies requirements for mechanical testing of metallic
materials to be used in the fabrication of spacecraft hardware.
This Standard establishes the requirements for most relevant test methods
carried out to assess the tensile, fatigue and fracture properties of metallic
materials. It does not give a complete review of all the existing test methods for
the evaluation of mechanical properties of metallic materials.
Furthermore, this Standard specifies requirements for the evaluation,
presentation and reporting of test results.
This standard may be tailored for the specific characteristic and constrains of a
space project in conformance with ECSS-S-ST-00.

Normative references
The following normative documents contain provisions which, through
reference in this text, constitute provisions of this ECSS Standard. For dated
references, subsequent amendments to, or revision of any of these publications
do not apply, However, parties to agreements based on this ECSS Standard are
encouraged to investigate the possibility of applying the more recent editions of
the normative documents indicated below. For undated references, the latest
edition of the publication referred to applies.

EN reference Reference in text Title
EN 16601-00-01 ECSS-S-ST-00-01 ECSS system — Glossary of terms
EN 16602-10-09 ECSS-Q-ST-10-09 Space product assurance — Nonconformance control
system
EN 16602-70 ECSS-Q-ST-70 Space product assurance — Materials, mechanical
parts and processes
EN 16602-70-37 ECSS-Q-ST-70-37 Space product assurance — Determination of the
susceptibility of metals to stress-corrosion cracking
EN 16602-70-46 ECSS-Q-ST-70-46 Space product assurance — Requirements for
manufacturing and procurement of threaded fasteners
ASTM E 139 Standard test methods for conducting creep, creep-
rupture, and stress-rupture tests of metallic materials
ASTM E 399 Standard test method for plane-strain fracture
toughness of metallic materials
ASTM E 466 Standard practice for conducing force controlled
constant amplitude axial fatigue tests of metallic
materials
ASTM E 561 Standard practice for R-curve determination
ASTM E 606 Standard practice for strain-controlled fatigue testing
ASTM E 647 Standard test method for measurement of fatigue
crack growth rates
ASTM E 739 Standard practice for statistical analysis of linear or
linarized stress-life (S-N) and strain-life (e-N) fatigue
data
ASTM E 1290 Standard test method for crack-tip opening displace-
ment (CTOD) fracture toughness measurement
ASTM E 1820 Standard test method for measurement of fracture
toughness
EN 10002-1 Metallic materials — Tensile testing — Part 1: Method
of test at ambient temperature
EN 10002-2 Metallic materials — Tensile testing — Part 2:
Verification of the force measuring system of the
tensile testing machines
EN 10002-4 Metallic materials — Tensile testing — Part 4:
Verification of the extensometers used in uniaxial
testing
ESDU 96013:1996 Fracture toughness (KIc) values of some aluminium
alloys
ISO 7539-6:2003 Corrosion of metals and alloys — Stress corrosion
testing — Part 6: Preparation and use of pre-cracked
specimens for tests under constant load or constant
displacement
Terms, definitions and abbreviated terms
3.1 Terms defined in other standards
For the purpose of this Standard, the terms and definitions from
ECSS-S-ST-00-01 and ECSS-Q-ST-70 apply.
3.2 Terms specific to the present standard
3.2.1 crack tip plastic zone
plastically deformed region in a material adjacent to a crack tip
3.2.2 creep
time-dependent increase in strain in a material resulting from force
3.2.3 damage tolerance
in a material or structure, the capability to withstand stresses or loads in the
presence of defects
3.2.4 failure
condition generally caused by break or collapse so that a structural element can
no longer fulfil its purpose
3.2.5 fatigue
in a material, the failure phenomenon which results from repeated fluctuation
of stress
3.2.6 fracture toughness
inherent resistance of a material in the presence of a crack-like defect
3.2.7 finite life range
life range, in which all test pieces before a predetermined number of cycles fail
3.2.8 mechanical properties
those properties of a material that are associated with elastic and inelastic
reaction when force is applied, or that involve the relationship between stress
and strain
3.2.9 mechanical testing
determination of mechanical properties
3.2.10 raw material
material from which specimens are manufactured
3.2.11 specimen
representative fraction of material tested or analysed in order to determine
mechanical properties
3.2.12 transition range
-6 -7
predetermined number of cycles of stress cycles (typically 5 x 10 to 5 x 10
cycles), where failure as well as non-failure occur.
3.2.13 threaded fastener
device composed by a cylindrical screwed bar provided with a head and a
metal collar, screwed internally, to fit the cylindrical bar that is to hold parts
firmly together in an assembly
3.2.14 weld heat affected zone (HAZ)
portion of material in a welded joint whose microstructure and physical
properties are affected by the heat input during welding
3.3 Abbreviated terms
For the purpose of this Standard, the abbreviated terms from ECSS-S-ST-00-01
and the following apply:
Abbreviation Meaning
American Society for Testing and Materials
ASTM
European Committee for Standardization
CEN
crack tip opening displacement
CTOD
engineering sciences data unit
ESDU
heat affected zone
HAZ
International Organization for Standardization
ISO
nonconformance report
NCR
non-destructive inspection
NDI
raw material certificate
RMC
3.4 Symbols
Symbol Meaning
compact tension specimen
C(T)
J-integral
J
J-integral plane-strain fracture toughness
JIc
stress intensity factor
K
stress intensity plane-strain fracture toughness
KIc
maximum stress intensity factor
Kmax
opening mode of loading
Mode I
stress ratio
R
specimen stress ratio
Rsx
middle tension specimen
M(T)
crack growth rate
da/dn
stress intensity factor range
ΔK
fatigue crack propagation threshold
ΔKth
threshold stress intensity factor for susceptibility
KISCC
to stress corrosion cracking
Principles
4.1 Overview
This Standard specifies requirements to conduct tests in order to characterize
mechanical behaviour and properties of metallic materials. Selection criteria of
mechanical tests are based on the significance and use of each specified test
method. Test methods, which are covered in this Standard, are characterized in
the following paragraphs.
4.2 Tensile test
Tensile tests provide information on the strength and ductility of materials
under uniaxial tensile stresses. Test results can be used in comparing materials,
alloy development, design and quality control. The test method covers the
tension testing of metallic materials in any form at room temperature, and
specifically the methods determine yield strength, yield point elongation,
tensile strength, elongation and reduction of area.
4.3 Fracture toughness test
4.3.1 Overview
This test refers to methods to determine fracture toughness of metallic materials
using the following parameters: stress intensity factor (K), J-integral (J), R-curve
and crack tip opening displacement (CTOD). The fracture toughness
determined in accordance with this method is for opening mode (Mode I) of
loading.
4.3.2 Determination of fracture toughness using
the K test method
Ic
This method provides the measurement of crack-extension resistance at the
start of a crack extension for slow rates of loading and when the crack-tip
plastic zone is small compared to both the crack size and to the specimen
dimension in the direction of the constraint.
The method covers the determination of linear elastic plane-strain fracture
toughness (KIc) of metallic materials by tests using a variety of fatigue-
precracked specimens.
4.3.3 Determination of fracture toughness using
the J test method
Ic
This method provides the measurement of crack-extension resistance near the
onset of stable crack extension for slow rates of loading and substantial plastic
deformation.
The method covers the determination of the J-integral plane-strain fracture
toughness (JIc) of metallic materials.
4.3.4 Characterization of fracture toughness
using the R-curve test method
This method provides a characterization of the resistance to fracture of metallic
materials during incremental slow stable crack extension and result from
growth of the plastic zone as the crack extends from a sharp notch. Materials
that can be tested for R-curve development are not limited by strength,
thickness, or toughness provided that specimens are of sufficient size to remain
predominantly elastic.
The method covers the determination of resistance to fracturing of metallic
materials by R-curves obtained by testing compact tension specimens C(T) or
middle tension specimens M(T).
4.3.5 Characterization of fracture toughness
using the CTOD test method
This test method provides a characterization of the fracture toughness of
metallic materials and is used for materials that exhibit a change from ductile to
brittle behaviour with decreasing temperature. This method is also used to
characterize the toughness of materials for which the properties and thickness
of interest preclude the determination of KIc fracture toughness in accordance
with ASTM E 399.
The specimen dimensions can affect the values of CTOD. For this reason
specimens of same dimensions are used when comparing test results.
The method covers the determination of critical crack tip opening displacement
(CTOD) values at one or more of several crack extension events. These CTOD is
used as measures of fracture toughness for metallic materials.
4.4 Fatigue test
4.4.1 General
Fatigue test refers to tests methods for the determination of fatigue strength of
metallic materials subjected to constant amplitude cycling loading.
4.4.2 Force controlled constant amplitude axial
fatigue test
The force controlled axial fatigue test is used to determine the effect of
variations in stress, material, geometry and surface condition on the fatigue
resistance of materials subjected to fatigue loading. The results can also be used
as a guideline for the selection of metallic materials for service under conditions
of repeated direct stress.
The method covers axial force controlled fatigue tests to obtain the fatigue
strength of materials in the fatigue regime, where the strains are predominately
elastic throughout the test.
4.4.3 Strain-controlled fatigue test
Strain-controlled fatigue is important for situations in which components or
portions of components undergo either mechanically or thermally induced
cyclic plastic strains that cause failure within relatively few cycles (i.e. fatigue
life < 10 cycles).
The method covers axial strain-controlled fatigue tests to obtain the fatigue
strength of materials in the fatigue regime where the strains are predominately
plastic.
4.5 Fatigue crack propagation test
4.5.1 Stable crack growth rate
Fatigue crack growth rate (da/dn) expressed as a function of crack tip stress
intensity factor range (∆K), characterizes a material’s resistance to stable crack
propagation under cyclic loading. Results from this test together with data on
toughness are used in the prediction of the damage tolerance behaviour
(typically the cycles or service period to grow a crack to a certain crack size, the
maximum permissible crack size and residual strength) and fatigue life
prediction for structural components.
The method covers the determination of stable crack growth rates from near-
threshold propagation regime to controlled crack propagation instability.
Results are expressed in terms of da/dn versus ∆K.
4.5.2 Crack propagation threshold
Although the fatigue-crack propagation threshold (∆Kth) is defined as the
asymptotic value of ∆K at which da/dn approaches zero, an operational, though
arbitrary, definition of ∆Kth is given for most materials. This value is defined as
∆K, which corresponds to a specified fatigue crack growth rate (typically for
-8
crack growth rates of 10 m/cycle or less).
It is found that the propagation threshold behaviour of long cracks can be
described in terms of stress ratio (R) as well as in terms of maximum stress
intensity Kmax, (see references [1], [2] and [3] in Annex D). From a practical point
of view, testing at constant Kmax allows to proceed faster compared to testing at
constant R, since load history effects are generally negligible. The approach is
based on the observation that for many alloys ∆Kth vs. Kmax relationships show a
quasi-linear dependency above certain Kmax values. Similarly, Kmax vs. R
relationships at low R values can be approximated by linear
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