oSIST prEN ISO 3845:2025

SLOVENSKI STANDARD
01-december-2025
Naftna in plinska industrija, vključno z nizkoogljično energijo - Metoda preskusa
ovalizacije s polnim obročem za oceno odpornosti jeklenih cevi proti razpokanju v
kislem okolju (ISO 3845:2024)
Oil and gas industries including lower carbon energy - Full ring ovalization test method
for the evaluation of the cracking resistance of steel line pipe in sour service (ISO
3845:2024)
Öl- und Gasindustrie einschließlich kohlenstoffarmer Energieträger - Vollring-
Ovalisierungsprüfverfahren für die Bewertung der Rissbeständigkeit von
Stahlleitungsrohren im sauren Betrieb (ISO 3845:2024)
Industries du pétrole et du gaz, y compris les énergies à faible teneur en carbone -
Méthode d'essai de déformation du diamètre d'une conduite en acier pour évaluer sa
tenue mécanique en environnement corrosif (ISO 3845:2024)
Ta slovenski standard je istoveten z: prEN ISO 3845
ICS:
75.200 Oprema za skladiščenje Petroleum products and
nafte, naftnih proizvodov in natural gas handling
zemeljskega plina equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

International
Standard
ISO 3845
First edition
Oil and gas industries including
2024-05
lower carbon energy — Full ring
ovalization test method for the
evaluation of the cracking resistance
of steel line pipe in sour service
Industries du pétrole et du gaz, y compris les énergies à
faible teneur en carbone — Méthode d'essai de déformation
du diamètre d'une conduite en acier pour évaluer sa tenue
mécanique en environnement corrosif
Reference number
ISO 3845:2024(en) © ISO 2024
ISO 3845:2024(en)
© ISO 2024
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
ii
ISO 3845:2024(en)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols and abbreviated terms. 6
5 Principle . 6
6 Reagents . 7
7 Apparatus . 8
7.1 Containment materials . .8
7.1.1 General .8
7.1.2 Lid and base .8
7.1.3 Seal rings .8
7.2 Internal loading components .8
7.3 External loading components .10
7.4 Loading component treatment .11
7.5 Ancillary components .11
8 Sampling .12
8.1 General . 12
8.2 Ultrasonic testing . 12
8.3 Magnetic particle testing/penetrant testing . 12
9 Procedure .12
9.1 General . 12
9.2 Test specimen . 12
9.2.1 Machining/Preparation . 12
9.2.2 Surface preparation . 13
9.2.3 Specimen loading . 13
9.3 Preparation of the test cell.17
9.4 Test duration and solution parameters .17
9.5 Test commencement .18
9.6 Monitoring .18
9.6.1 Test solution .18
9.6.2 Ultrasonic testing .19
9.6.3 Hydrogen permeation .19
9.6.4 Galvanic coupling .19
9.7 Test completion .19
9.8 Secondary testing .19
9.9 Evaluation of test specimen .19
9.9.1 General .19
9.9.2 Post-test non-destructive testing . 20
9.9.3 Metallographic examination . 20
10 Test report .22
Annex A (normative) Ultrasonic testing (UT) .24
Annex B (normative) Strain gauge installation .29
Annex C (normative) Analysis of test solution – Iodometric titration procedure.37
Annex D (informative) Summary of the full ring test procedure .40
Annex E (informative) Examples of types of cracking .46
Annex F (informative) Example of full ring test report and loading report .48

iii
ISO 3845:2024(en)
Annex G (informative) Guidance on acceptance criteria .51
Bibliography .52

iv
ISO 3845:2024(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
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Any trade name used in this document is information given for the convenience of users and does not
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This document was prepared by Technical Committee ISO/TC 67, Oil and gas industries including lower
carbon energy.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

v
ISO 3845:2024(en)
Introduction
Sour service cracking problems in susceptible steel line pipe are caused by the various forms of hydrogen
damage due to the presence of wet hydrogen sulfide (H S). The main mechanisms are hydrogen-induced
cracking (HIC) or stepwise cracking (SWC), sulfide stress cracking (SSC) and stress-oriented hydrogen-
induced cracking (SOHIC). An industry-proven technique for assessing the cracking resistance of steel line
pipe is to stress a full ring pipe specimen in a sour environment.
The advantages of the full ring test specified in this document are that it is not necessary to pressurize the
line pipe full ring specimen to achieve the required stress, and residual stresses are retained. Equivalent
internal stresses can be produced by ovalization of the pipe using mechanical means.
Additional advantages are more representative samples, when compared to machined four-point bend
specimens and single-sided exposure can allow in-situ inspection during test exposure.
A known stress is exerted at two regions on a full ring section of steel pipe. The pipe specimen is then
exposed internally to the sour test solution.
Ultrasonic testing can be conducted regularly on internally loaded test specimens during the exposure period
to monitor crack initiation and propagation. Hydrogen permeation measurements may also be conducted.
Both crack initiation and propagation can therefore be monitored. Finally, a metallurgical examination is
undertaken to classify any indications found by non-destructive testing (NDT), such as visual inspection,
magnetic particle testing (MT), penetrant testing (PT) or ultrasonic testing (UT).
The method has been in use since 1984, but in 1991 a Joint Industry Sponsored Project was set up with
the aim of systematically developing, defining and validating the full ring test. The resultant test method
designed to determine the susceptibility of steel line pipe, bends, flanges and fittings, including all associated
welds to hydrogen damage caused by exposure to sour environments, was published by the UK HSE as OTI
[1]
95 635 and subsequently in 2016 as BS 8701, prior to adoption as ISO 3845.

vi
International Standard ISO 3845:2024(en)
Oil and gas industries including lower carbon energy — Full
ring ovalization test method for the evaluation of the cracking
resistance of steel line pipe in sour service
WARNING — The use of this document can involve hazardous materials, operations and equipment.
It does not purport to address all the safety or environmental problems associated with its use.
Attention is drawn to national and health safety practices and regulations regarding the use of
hazardous materials prior to use, in particular for hydrogen sulfide.
1 Scope
This document gives a method for determining the resistance to cracking of steel pipes in sour service.
This test method employs a full-scale test specimen consisting of a short length of pipe (a ‘full ring’), sealed
at each end to contain the sour test environment within. The test method applies to any pipe; seamless,
longitudinally welded (with or without filler), helical welded, and to girth welds between pipes.
NOTE 1 The specimen is usually a pipe but can also consist of flange neck or section of a bend, or other tubular
component or a combination of the above.
NOTE 2 This test method can also be used for corrosion resistant alloys (CRAs).
The method utilizes ovalization by mechanical loading to produce a circumferential stress, equal to the
target hoop stress, at two diametrically opposite locations on the inside surface of the test specimen. The
test specimen is then subjected to single sided exposure to the sour test environment.
NOTE 3 The test also allows measurement of hydrogen permeation rates.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements 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 2400, Non-destructive testing — Ultrasonic testing — Specification for calibration block No. 1
ISO 3059, Non-destructive testing — Penetrant testing and magnetic particle testing — Viewing conditions
ISO 3452 (all parts), Non-destructive testing – Penetrant testing
ISO 4787, Laboratory glass and plastic ware — Volumetric instruments — Methods for testing of capacity and for use
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
ISO 7963, Non-destructive testing — Ultrasonic testing — Specification for calibration block No. 2
ISO 8044, Corrosion of metals and alloys — Vocabulary
ISO 8501-1, Preparation of steel substrates before application of paints and related products — Visual
assessment of surface cleanliness — Part 1: Rust grades and preparation grades of uncoated steel substrates and
of steel substrates after overall removal of previous coatings
ISO 9934 (all parts), Non-destructive testing — Magnetic particle testing
ISO 11666, Non-destructive testing of welds — Ultrasonic testing — Acceptance levels

ISO 3845:2024(en)
ISO 16810, Non-destructive testing – Ultrasonic testing – General principles
ISO 17635, Non-destructive testing of welds — General rules for metallic materials
ISO 17638, Non-destructive testing of welds — Magnetic particle testing
ISO 17640:2018, Non-destructive testing of welds — Ultrasonic testing — Techniques, testing levels, and
assessment
ISO 22232 (all parts), Non-destructive testing — Characterization and verification of ultrasonic test equipment
ISO 23277, Non-destructive testing of welds — Penetrant testing — Acceptance levels
ASTM D1193, Standard Specification for Reagent Water
ASTM E1237, Standard Guide for Installing Bonded Resistance Strain Gages
ASTM F21, Standard test method for hydrophobic surface films by the atomizer test
NACE TM0284: 2016, Evaluation of Pipeline and Pressure Vessel Steels for Resistance to Hydrogen-Induced
Cracking
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8044 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
ancillary components
parts of the apparatus necessary for the test which are not the loading components to impart stress (3.26)
3.2
corrosion-resistant alloy
CRA
alloy intended to be resistant to general and localized corrosion of oilfield environments that are corrosive
to carbon steels
[SOURCE: ISO 15156-1:2020, 3.6]
3.3
imperfection
discontinuity or irregularity in the product wall or on the product surface that is detectable by inspection
methods outlined in this document
3.4
indication
evidence obtained by non-destructive inspection
3.5
girth weld
butt weld joining one pipe to another (or bend or flange)
3.6
hardness
resistance of metal to plastic deformation (3.16), usually determined by indentation

ISO 3845:2024(en)
3.7
heat-affected zone
HAZ
portion of base metal not melted during brazing, cutting or welding (3.31), but whose microstructure (3.14)
and properties are altered by the thermal cycle of these processes
3.8
helical weld
DEPRECATED: spiral weld
weld running helically (spirally) around the circumference of a pipe formed from strip
3.9
hydrogen-induced cracking
HIC
planar cracking that occurs in carbon and low alloy steels (3.12) when atomic hydrogen diffuses into the
steel and then combines to form molecular hydrogen at trap sites
[SOURCE: ISO 15156-1:2020, 3.12, modified — Note 1 to entry has been removed.]
3.10
hydrogen permeation
process of atomic hydrogen diffusion through a metal
3.11
longitudinal weld
straight weld running along the longitudinal axis of a pipe
3.12
low alloy steel
steel with a total alloying element content of less than about 5 % mass fraction, but more than specified for
carbon steel
[SOURCE: ISO 15156-1:2020, 3.15]
3.13
measured strain
ε , ε , ε
1 2 3
surface strain (3.24) as measured by various techniques in one or more of three known directions at the surface
3.14
microstructure
structure of a metal as revealed by microscopic examination of a suitably prepared specimen
[SOURCE: ISO 15156-1:2020, 3.16]
3.15
modulus of elasticity
Young’s modulus
E
ratio of tensile or compressive stress (3.26) to corresponding strain (3.24) below the elastic limit
3.16
plastic deformation
permanent deformation caused by straining beyond the elastic limit
3.17
Poisson’s ratio
v
dimensionless material constant (approximately constant for steel) given by the ratio of contraction/
expansion per unit length tangential to the direction of loading over the expansion/contraction per unit
length in the direction of loading

ISO 3845:2024(en)
3.18
principal strain
ε
p
maximum and minimum strain (3.24) levels existing at a point on the test surface acting at 90° to each other
as calculated from measured strain (3.13) values
3.19
residual stress
σ
res
stress (3.26) present in a component free of external forces or thermal gradients
[SOURCE: ISO 15156-1:2020, 3.18, modified — The symbol σ has been added.]
res
3.20
sour environment
environment where hydrogen sulfide exists in the presence of water
3.21
specific service
conditions of application for the materials/components for which testing is defined to match the customer’s
requirements
Note 1 to entry: Fitness-for-purpose has also been historically used to define these same requirements.
3.22
specified minimum yield strength
SMYS
minimum yield strength (3.34) permitted for a given grade of material in product specifications
3.23
stepwise cracking
SWC
cracking that connects hydrogen-induced cracks on adjacent planes in a steel
Note 1 to entry: This term describes the crack appearance. The linking of hydrogen-induced cracks to produce stepwise
cracking is dependent on the local strain (3.24) between the cracks and the embrittlement of the surrounding steel by
dissolved hydrogen. HIC/SWC is usually associated with low-strength plate steels used in the production of pipes and
vessels.
[SOURCE: ISO 15156-1:2020, 3.21]
3.24
strain
ε
dimensionless ratio of the change in length per unit length (e.g. mm/mm)
Note 1 to entry: It is normally expressed in parts per million (ε × 10 ) of microstrain (µε).
3.25
strain gauge
device using electrical resistance, which changes in proportion to applied strain (3.24)
3.26
stress
σ
applied force per unit area existing on any object as a result of external mechanical or thermal influences
acting in that direction
ISO 3845:2024(en)
3.27
stress-oriented hydrogen-induced cracking
SOHIC
staggered small cracks formed approximately perpendicular to the principal stress (3.26) (residual or
applied) resulting in a “ladder-like” crack array linking (sometimes small) pre-existing HIC
Note 1 to entry: The mode of cracking can be categorized as SSC (3.28) caused by a combination of external stress
and the local strain (3.24) around hydrogen-induced cracks. SOHIC is related to SSC and HIC/SWC (3.23). It has been
observed in parent metal of longitudinally welded pipe and in the heat-affected zone (HAZ) (3.7) of welds in pressure
vessels. SOHIC is a relatively uncommon phenomenon usually associated with low-strength ferritic pipe and pressure
vessel steels.
[SOURCE: ISO 15156-1:2020, 3.23]
3.28
sulfide stress cracking
SSC
cracking of metal involving corrosion and tensile stress (3.29) (residual and/or applied) in the presence of
water and H S
Note 1 to entry: SSC is a form of hydrogen stress cracking (HSC) and involves the embrittlement of the metal by atomic
hydrogen that is produced by acid corrosion on the metal surface. Hydrogen uptake is promoted in the presence of
sulfides. The atomic hydrogen can diffuse into the metal, reduce ductility, and increase susceptibility to cracking.
High-strength metallic materials and hard weld zones are prone to SSC.
[SOURCE: ISO 15156-1:2020, 3.24]
3.29
tensile stress
ratio of load to original cross-sectional area
Note 1 to entry: These stresses include axial or longitudinal, circumferential or hoop and residual.
3.30
ultrasonic testing
testing of material by ultrasound for the presence of imperfections (3.3)
3.31
welding
joining of two metallic materials, usually by fusion techniques
3.32
weldment
portion of a component on which welding (3.31) has been performed, including the weld metal (3.33), the
heat-affected zone (HAZ) (3.7), and the adjacent parent metal
[SOURCE: ISO 15156-2:2020, 3.24, modified — The abbreviated term for "heat-affected zone", HAZ, has
been added.]
3.33
weld metal
portion of a weldment (3.32) that has been molten during welding (3.31)
3.34
yield strength
stress (3.26) at which a material exhibits a specified deviation from the proportionality of stress to strain (3.24)
Note 1 to entry: The deviation is expressed in terms of strain by either the offset method (usually at a strain of 0,2 %)
or the total-extension-under-load method (usually at a strain of 0,5 %).

ISO 3845:2024(en)
4 Symbols and abbreviated terms
AYS actual yield strength
CAR crack area ratio
CRA corrosion-resistant alloy
DAC distance-amplitude-corrected
E modulus of elasticity
EPDM ethylene propylene diene monomer
EPM ethylene propylene copolymer
HAZ heat-affected zone
HIC hydrogen-induced cracking
MT magnetic particle testing
NBR nitrile butadiene rubber
NDT non-destructive testing
PT penetrant testing
PTFE polytetrafluoroethylene
R 0,2 % proof stress in accordance with ISO 6892-1
p0,2
SOHIC stress-oriented hydrogen-induced cracking
SMYS specified minimum yield strength
SSC sulfide stress cracking
SWC step-wise cracking
SZC soft-zone cracking
UT ultrasonic testing
ε strain
ε principal strain
p
ʋ Poisson's ratio
σ stress
σ principal stress
p
σ residual stress
res
5 Principle
A short length of pipe (a ‘full ring’) is mechanically loaded to produce a circumferential stress equal to the
target hoop stress at two diametrically opposite locations on the inside surface of the test specimen. The
test specimen is subjected to a predetermined stress by ovalization and exposed to a sour environment.
Testing is undertaken within an enclosure or in a restricted area.

ISO 3845:2024(en)
The test specimen may be monitored throughout the test exposure to determine the extent of development
of hydrogen damage due to the presence of wet hydrogen sulfide (H S). It is then subjected to post-test non-
destructive testing and metallographic examination.
6 Reagents
6.1 The following reagent grade or higher-purity chemicals shall be used:
— sodium acetate, CH COONa;
— sodium chloride, NaCl;
— acetic acid, CH COOH;
— hydrochloric acid, HCl;
— sodium hydroxide, NaOH.
6.2 The following gases shall be used:
— hydrogen sulfide, 99,5 % minimum;
— carbon dioxide, 99,995 % minimum;
— inert gas used for the removal of oxygen, such as nitrogen, argon, or other non-reactive gas, 99,998 %
minimum.
6.3 Water, distilled or deionized, conforming to the minimum purity requirements of Type IV of ASTM
D1193 shall be used.
6.4 Test environment
6.4.1 General
The test solution used shall be reported for each test. All reagents added to the test solution shall be
measured to ±1,0 % of the quantities specified.
The test solution shall be prepared in a separate sealed vessel followed by sparging with inert gas prior to
transferring the test solution to the test cell, which has been subjected to inert gas purging in advance (see 9.5).
The test solution pH before transfer to the test cell shall be measured and verified to conform with
requirements.
The H S concentration in the solution shall be measured using the iodometric titration method described in
Annex C, or other equivalent method (e.g. photometric measurement).
6.4.2 Test solutions
The following test solutions shall be used depending on the specific test requirements:
a) NACE TM0284 Solution A: This test solution shall consist of a mass fraction of 5,0 % NaCl and 0,50 %
CH COOH in distilled or deionized water (i.e. 50,0 g of NaCl and 5,00 g of CH COOH dissolved in 945 g of
3 3
distilled or deionized water). The initial pH shall be 2,7 ± 0,1. Alteration of the test solution chemistry to
adjust pH is not allowed. If the test solution pH is out of range the solution shall be discarded.

ISO 3845:2024(en)
b) NACE TM0284 Solution C ('fitness for purpose' solution): This test solution shall consist of a mass
fraction of 5,0 % NaCl and 0,40 % CH COONa in distilled or deionized water (i.e. 50,0 g of NaCl and 4,00 g
of CH COONa dissolved in 946 g of distilled or deionized water).
The target pH shall be defined by the customer. The initial pH shall be adjusted to the target pH ±0,2 by
addition of HCl or NaOH before saturation with H S or the H S/CO gas mixture.
2 2 2
c) Customer specified/field specific test solution.
NOTE a) and b) are equivalent to the test environments defined in ISO 15156-2:2020, Annex B.
6.4.3 Test gas composition
One of the following test gases shall be used depending on the specific test requirements:
a) NACE TM0284 Solution A: H S;
b) NACE TM0284 Solution C: H S or test gas mixtures consisting of H S and CO ;
2 2 2
c) customer specified/field specific test solution: H S or test gas mixtures consisting of H S and CO or
2 2 2
H S and N .
2 2
The test gas or mixture composition shall be defined by the customer. Pre-mixed commercial test gas
mixtures shall have a composition verified by analysis. Continuously-blended test gas mixtures shall have
a composition verified by measurement. Each pure component gas used for continuously-blended test gas
mixtures shall conform to the requirements of 6.2.
7 Apparatus
7.1 Containment materials
7.1.1 General
All materials employed in the test equipment shall be resistant to the test environment over the duration of
the test.
7.1.2 Lid and base
Lid and base shall be made of:
a) polymethylmethacrylate (also known as acrylic) of appropriate thickness to avoid deformation with
surfaces pre-treated with 50 % acetic acid solution for 1 h to 2 h;
b) PTFE coated/lined steel; or
c) other materials conforming to 7.1.1.
7.1.3 Seal rings
Seal rings shall be made from material conforming to 7.1.1
NOTE NBR, EPM/EPDM and PTFE have been found to be suitable seal materials.
7.2 Internal loading components
An example of the internal loading components that may be used to apply the stress to the specimen is
shown in Figure 1.
ISO 3845:2024(en)
The turnbuckle consists of a barrel with a left- and right-handed thread bore, into which two sections screw
with the appropriate thread.
NOTE 1 ACME (ballistic) threading has been found to be suitable. Austenitic stainless steel has been found to be
reusable and has not led to detrimental galvanic effects.
The face of the load distribution block which fits against the ring section is profiled to fit the ring section to
ensure even load application.
The load distribution blocks shall consist of a galvanically compatible material to that of the internal surface
of the specimen. Loading blocks shall be sufficiently rigid so that the applied load is maintained over the
duration of the test.
NOTE 2 Low alloy steel has been found to be suitable.

ISO 3845:2024(en)
Key
1 pipe inside diameter 5 weldment
2 closed jack position 6 hydraulic jack
3 load distribution blocks 7 spacer block
4 turnbuckle 8 height adjustable supports
Figure 1 — Example of internal loading components
7.3 External loading components
External loading of the test specimen may be required, e.g. for pipe diameters <300 mm or with larger
diameter pipe of thick wall/diameter combinations which preclude internal loading. Figure 2 shows a
typical configuration of specimen and loading components. External loading imparts the target strain at the

ISO 3845:2024(en)
centre of the contact location on each block and, as such, precludes the in-test UT assessment. Internal strain
gauging is used to monitor the load application.
Loading blocks shall be sufficiently rigid so that the applied load is maintained over the duration of the test.
The internal face (contact surface) in the centre of the block shall have a machined longitudinal slot with
a minimum arc length of 75 mm or 5 % of the pipe circumference, whichever is greater, and should have
a radius typically equivalent to 1,05 to 1,10 times the anticipated maximum external radius of the test
specimen under loading.
Key
1 loading blocks with clearance holes
2 radius longitudinal slot
3 ring specimen
4 bolts with nuts/washers
Figure 2 — Example of external loading components
7.4 Loading component treatment
Both internal and external forms of loading components (see Figures 1 and 2) shall be designed for repeated
use. At the conclusion of the full ring test, any loading components that have been submerged within the test
solution shall be thoroughly wire brushed and, where practicable, submerged in oil until required for further
use. On removal from the oil, the components shall be degreased. At no time shall loading components of
either form come into contact with greases containing copper (Cu) or molybdenum disulfide (MoS ).
7.5 Ancillary components
Ancillary components in contact with or exposed to the test environment, such as thermowells, shall
conform to 7.1.1.
ISO 3845:2024(en)
8 Sampling
8.1 General
The pipe sample(s) shall be representative of the commercial product and any weld shall be made using an
appropriate welding procedure.
NOTE Additional material can be required to provide the tensile specimens for the determination of the AYS.
The pipe sample(s) to be tested shall be examined as described in 8.2 and 8.3 to ensure freedom from
imperfections to permit specimen extraction.
8.2 Ultrasonic testing
The external surface of the sample shall be 100 % inspected using the ultrasonic test procedure detailed in
Annex A. The sample shall be inspected using a compression probe and shear wave probes of angles 45°, 60°
and 70°. All indications shall be recorded.
NOTE The purpose of this inspection is to confirm suitability of the sample for extraction of the test specimen(s)
and to provide a “fingerprint” which will enable a quantitative comparison to be made with later inspections and to
avoid misinterpretation of pre-existing indications.
8.3 Magnetic particle testing/penetrant testing
The entire internal surface of the sample shall be inspected using magnetic particle testing for carbon and
low alloy steel, or penetrant testing for CRAs.
Magnetic particle testing shall be performed using a documented procedure conforming to the ISO 9934
series, ISO 3059, ISO 17635 and ISO 17638. Penetrant testing shall be performed using a documented
procedure conforming to the ISO 3452 series, ISO 3059 and ISO 23277.
9 Procedure
9.1 General
Where the test specimen contains a girth weld, it shall be positioned at the mid-length. To retain the residual
stress produced during manufacture and welding, the length of the test specimen shall be equal to or greater
than the outer diameter.
Characterization of residual stress in the test specimen should be considered to aid post-test analysis.
If the test specimen contains a specific region for assessment (e.g. a repair weld or strained area), then this
position shall be clearly marked on the external surface so that the applied load can be aligned accordingly.
NOTE 9.2.3.1 provides guidance on the alignment of seam welds, repair welds, etc. to optimize the data generated
per test specimen.
The specimen shall be grit-blasted and the ends prepared so that they can later be fitted with gas-tight seals.
An illustrated summary of the procedure is given in Annex D.
9.2 Test specimen
9.2.1 Machining/Preparation
The length of the test specimen shall be equal to or greater than the outside diameter of the line pipe sample.
The ends on the test specimen shall be machined to provide clean, flat surfaces. A groove may then be
machined in the end faces to accommodate an o-ring seal.

ISO 3845:2024(en)
9.2.2 Surface preparation
9.2.2.1 Carbon and low alloy steel
The internal surface shall be in one of two conditions:
a) prepared by grit blasting using grit with a nominal maximum diameter of 1,0 mm without re-circulation
to a minimum grade Sa. 2,5 in accordance with ISO 8501-1.
NOTE 20-40 mesh (0,84 mm to 0,40 mm) garnet grit has been found to be suitable.
b) other surface conditions as specified by the customer specified, including as-received to retain surface
features of interest.
To avoid flash rusting of the cleaned surface, after completion of grit blasting or other surface preparation,
the ring specimen shall be stored in dry air or an inert gas atmosphere prior to strain gauging, loading and
sealing.
9.2.2.2 Corrosion-resistant alloys
The internal surface shall be degreased and the adequacy of degreasing verified in accordance with
ASTM F21 or equivalent. The surface shall not be abraded.
NOTE Other surface treatments can be used if specified by the customer.
9.2.3 Specimen loading
9.2.3.1 Position of maximum stress
The specimen shall be marked such that the maximum stress shall be applied at:
a) the area adjacent to the seam weld (if present);
b) any ultrasonic indications found in the girth weld or weld repair; or
c) any other customer specified location.
NOTE 1 It is therefore useful to consider these points prior to producing the test sample, as it is possible for the
repair area in a girth weld to be positioned 180° from a seam weld, in which case both critical areas can be tested
simultaneously at or above the minimum test stress.
NOTE 2 It is common industrial practice when lengths of seam welded pipe are welded together, that the two pipe
seam welds are a minimum of 30° apart. For efficient testing, placing the seam welds 180° apart is useful as both
seams can then be tested simultaneously at or above the minimum test stress.
NOTE 3 Annex B provides details of the strain gauging technique and also shows the various combinations of ring
specimens that can be tested.
9.2.3.2 Strain gauge locations
The ring specimen shall be loaded by internal or external loading as illustrated in Figure 3 and Figure 4. To
monitor the load and determine the stress during application of the load, strain gauges shall be attached to
the internal surface in accordance with Annex B.

ISO 3845:2024(en)
Key
1 0° position for maximum target stress 4 turnbuckle
2 load distribution blocks 5 180° position for maximum target stress
3 strain gauges 6 ring specimen
Figure 3 — Example of full ring test configuration using internal loading technique
Key
1 loading blocks with clearance holes 4 strain gauges
2 0° position for maximum target stress 5 180° position for maximum target stress
3 bolts with nuts/washers 6 ring specimen
Figure 4 — Example of full ring test configuration using external loading technique

ISO 3845:2024(en)
9.2.3.3 Dimensional checks pre-loading
Measure and record:
— the specimen length;
— the wall thickness of the pipe at 0° and 180° positions;
— the outer diameter across 0° to 180° positions;
— the outer diameter across 90° to 270° positions;
— the position
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