ISO 15156-2:2020
(Main)Petroleum and natural gas industries — Materials for use in H2S-containing environments in oil and gas production — Part 2: Cracking-resistant carbon and low-alloy steels, and the use of cast irons
Petroleum and natural gas industries — Materials for use in H2S-containing environments in oil and gas production — Part 2: Cracking-resistant carbon and low-alloy steels, and the use of cast irons
This document gives requirements and recommendations for the selection and qualification of carbon and low-alloy steels for service in equipment used in oil and natural gas production and natural gas treatment plants in H2S-containing environments, whose failure can pose a risk to the health and safety of the public and personnel or to the environment. It can be applied to help to avoid costly corrosion damage to the equipment itself. It supplements, but does not replace, the materials requirements of the appropriate design codes, standards or regulations. This document addresses the resistance of these steels to damage that can be caused by sulfide stress cracking (SSC) and the related phenomena of stress-oriented hydrogen-induced cracking (SOHIC) and soft-zone cracking (SZC). This document also addresses the resistance of these steels to hydrogen-induced cracking (HIC) and its possible development into stepwise cracking (SWC). This document is concerned only with cracking. Loss of material by general (mass loss) or localized corrosion is not addressed. Table 1 provides a non-exhaustive list of equipment to which this document is applicable, including exclusions. This document applies to the qualification and selection of materials for equipment designed and constructed using load controlled design methods. For design utilizing strain-based design methods, see ISO 15156-1:2020, Clause 5. Annex A lists SSC-resistant carbon and low alloy steels, and A.2.4 includes requirements for the use of cast irons. This document is not necessarily suitable for application to equipment used in refining or downstream processes and equipment.
Industries du pétrole et du gaz naturel — Matériaux pour utilisation dans des environnements contenant de l'hydrogène sulfuré (H2S) dans la production de pétrole et de gaz — Partie 2: Aciers au carbone et aciers faiblement alliés résistant à la fissuration, et utilisation de fontes
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INTERNATIONAL ISO
STANDARD 15156-2
Fourth edition
2020-11
Petroleum and natural gas
industries — Materials for use in H S-
2
containing environments in oil and
gas production —
Part 2:
Cracking-resistant carbon and low-
alloy steels, and the use of cast irons
Industries du pétrole et du gaz naturel — Matériaux pour utilisation
dans des environnements contenant de l'hydrogène sulfuré (H S) dans
2
la production de pétrole et de gaz —
Partie 2: Aciers au carbone et aciers faiblement alliés résistants à la
fissuration, et utilisation de fontes
Reference number
ISO 15156-2:2020(E)
©
ISO 2020
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ISO 15156-2:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
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ISO 15156-2:2020(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 3
4 Symbols and abbreviated terms . 6
5 Purchasing information . 7
6 Factors affecting the behaviour of carbon and low alloy steels in H S-containing
2
environments . 7
7 Qualification and selection of carbon and low-alloy steels with resistance to SSC,
SOHIC and SZC . 8
7.1 Option 1 — Selection of SSC-resistant steels (and cast irons) using A.2 . 8
7.1.1 For p < 0,3 kPa (0,05 psi) . 8
HS
2
7.1.2 For p ≥ 0,3 kPa (0,05 psi) . 8
HS
2
7.2 Option 2 — Selection of steels for specific sour-service applications or for ranges
of sour service . 8
7.2.1 Sulfide stress cracking . 8
7.2.2 SOHIC and SZC .10
7.3 Hardness requirements .10
7.3.1 General.10
7.3.2 Parent metals .10
7.3.3 Welds .11
7.4 Other fabrication methods .16
8 Evaluation of carbon and low alloy steels for their resistance to HIC/SWC .16
9 Marking, labelling, and documentation .17
Annex A (normative) SSC-resistant carbon and low alloy steels (and requirements and
recommendations for the use of cast irons) .18
Annex B (normative) Qualification of carbon and low-alloy steels for H S service by
2
laboratory testing .27
Annex C (informative) Determination of H S partial pressure and use of alternative parameters .35
2
Annex D (informative) Recommendations for determining pH .40
Annex E (informative) Information that should be supplied for material purchasing .45
Bibliography .47
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ISO 15156-2:2020(E)
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 documents 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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 67, Materials, equipment and offshore
structures for petroleum, petrochemical and natural gas industries, in collaboration with the European
Committee for Standardization (CEN) Technical Committee CEN/TC 12, Materials, equipment and
offshore structures for petroleum, petrochemical and natural gas industries, in accordance with the
Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This fourth edition cancels and replaces the third edition (ISO 15156-2:2015), which has been
technically revised. The main changes compared to the previous edition are as follows:
— corrections of temperature conversion for welding (see A.2.1.4), vold deformation and stress relief
(see A.2.1.6), identification stamping (see A.2.1.9), tubulars and tubular components (see A.2.2.3.4),
compressor impellers (see A.2.3.3.2);
— title change from Shear rams to Rams in A.2.3.2.2;
— addition of C110 and changes the designation of C95 to R95 in Table A.3;
— reference change to NACE TM0316 in Table B.1;
— addition of reference to BS 8701 in B.4.3;
— changes and additions to Table B.3;
— modification of Annex C to include alternative parameters and expanded explanation for the use of
chemical activity and fugacity, and to provide some general guidance for the use of thermodynamic
modeling for the determination of environmental severity.
A list of all parts in the ISO 15156 series can be found on the ISO website.
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.
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ISO 15156-2:2020(E)
Introduction
The consequences of sudden failures of metallic oil and gas field components, associated with their
exposure to H S-containing production fluids, led to the preparation of the first edition of NACE MR0175,
2
which was published in 1975 by the National Association of Corrosion Engineers, now known as NACE
International.
The original and subsequent editions of NACE MR0175 established limits of H S partial pressure above
2
which precautions against sulfide stress cracking (SSC) were always considered necessary. They
also provided guidance for the selection and specification of SSC-resistant materials when the H S
2
thresholds were exceeded. In more recent editions, NACE MR0175 has also provided application limits
for some corrosion-resistant alloys, in terms of environmental composition and pH, temperature and
H S partial pressures.
2
In separate developments, the European Federation of Corrosion issued EFC Publication 16 in 1995 and
EFC Publication 17 in 1996. These documents are generally complementary to those of NACE though
they differed in scope and detail.
In 2003, the publication of the ISO 15156-series and NACE MR0175/ISO 15156 was completed for the
first time. These technically identical documents utilized the above sources to provide requirements
and recommendations for materials qualification and selection for application in environments
containing wet H S in oil and gas production systems. They are complemented by NACE TM0177 and
2
NACE TM0284 test methods.
The revision of this document, i.e. ISO 15156-2,involves a consolidation of all changes agreed
and published in the Technical Circular 1, ISO 15156-2:2015/Cir.1:2017, the Technical Circular 2,
ISO 15156-2:2015/Cir.2:2018 and the Technical Circular 3, ISO 15156-2:2015/Cir.3:2019, published by
the ISO 15156 series Maintenance Agency secretariat at DIN.
The changes were developed by and approved by the ballot of, representative groups from within
the oil and gas production industry. The great majority of these changes stem from issues raised by
document users. A description of the process by which these changes were approved can be found at
the ISO 15156 series maintenance website: www .iso .org/ iso15156maintenance.
When found necessary by oil and gas production industry experts, future interim changes to this
document will be processed in the same way and will lead to interim updates to this document in
the form of Technical Corrigenda or Technical Circulars. Document users should be aware that such
documents can exist and can impact the validity of the dated references in this document.
The ISO 15156 series Maintenance Agency at DIN was set up after approval by the ISO Technical
Management Board given in document 34/2007. This document describes the make up of the agency,
which includes experts from NACE, EFC and ISO/TC 67, and the process for approval of amendments.
It is available from the ISO 15156 series maintenance website and from the ISO/TC 67 Secretariat. The
website also provides access to related documents that provide more detail of the ISO 15156 series
maintenance activities.
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INTERNATIONAL STANDARD ISO 15156-2:2020(E)
Petroleum and natural gas industries — Materials
for use in H S-containing environments in oil and gas
2
production —
Part 2:
Cracking-resistant carbon and low-alloy steels, and the use
of cast irons
WARNING — Carbon and low-alloy steels and cast irons selected using this document are
resistant to cracking in defined H S-containing environments in oil and gas production but
2
not necessarily immune to cracking under all service conditions. It is the equipment user's
responsibility to select the carbon and low alloy steels and cast irons suitable for the intended
service.
1 Scope
This document gives requirements and recommendations for the selection and qualification of carbon
and low-alloy steels for service in equipment used in oil and natural gas production and natural gas
treatment plants in H S-containing environments, whose failure can pose a risk to the health and safety
2
of the public and personnel or to the environment. It can be applied to help to avoid costly corrosion
damage to the equipment itself. It supplements, but does not replace, the materials requirements of the
appropriate design codes, standards or regulations.
This document addresses the resistance of these steels to damage that can be caused by sulfide stress
cracking (SSC) and the related phenomena of stress-oriented hydrogen-induced cracking (SOHIC) and
soft-zone cracking (SZC).
This document also addresses the resistance of these steels to hydrogen-induced cracking (HIC) and its
possible development into stepwise cracking (SWC).
This document is concerned only with cracking. Loss of material by general (mass loss) or localized
corrosion is not addressed.
Table 1 provides a non-exhaustive list of equipment to which this document is applicable, including
exclusions.
This document applies to the qualification and selection of materials for equipment designed and
constructed using load controlled design methods. For design utilizing strain-based design methods,
see ISO 15156-1:2020, Clause 5.
Annex A lists SSC-resistant carbon and low alloy steels, and A.2.4 includes requirements for the use of
cast irons.
This document is not necessarily suitable for application to equipment used in refining or downstream
processes and equipment.
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ISO 15156-2:2020(E)
Table 1 — List of equipment
This document is applicable to materials used
Exclusions
for the following equipment
Drilling, well construction and well-servicing Equipment exposed only to drilling fluids of controlled
a
equipment composition
Drill bits
b
Blowout preventer (BOP) shear blades
Drilling riser systems
Work strings
c
Wireline and wireline equipment
Surface and intermediate casing
d
Wells, including subsurface equipment, gas lift Sucker rod pumps and sucker rods
equipment, wellheads and christmas trees
Electric submersible pumps
Other artificial lift equipment
Slips
Flow-lines, gathering lines, field facilities and field Crude oil storage and handling facilities operating at a
processing plants total absolute pressure below 0,45 MPa (65 psi)
Water-handling equipment Water-handling facilities operating at a total absolute
pressure below 0,45 MPa (65 psi)
Water injection and water disposal equipment
Natural gas treatment plants —
Transportation pipelines for liquids, gases and Lines handling gas prepared for general commercial
multiphase fluids and domestic use
For all equipment above Components loaded only in compression
a
See A.2.3.2.3 for more information.
b
See A.2.3.2.1 for more information.
c
Wireline lubricators and lubricator connecting devices are not excluded.
d
For sucker rod pumps and sucker rods, reference can be made to NACE MR0176.
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 6506 (all parts), Metallic materials — Brinell hardness test
ISO 6507 (all parts), Metallic materials — Vickers hardness test
ISO 6508 (all parts), Metallic materials — Rockwell hardness test
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
ISO 10423, Petroleum and natural gas industries — Drilling and production equipment — Wellhead and
christmas tree equipment
ISO 15156-1:2020, Petroleum and natural gas industries — Materials for use in H S-containing
2
environments in oil and gas production — Part 1: General principles for selection of cracking-resistant
materials
ISO 15156-3, Petroleum and natural gas industries — Materials for use in H S-containing environments in
2
oil and gas production — Part 3: Cracking-resistant CRAs (corrosion-resistant alloys) and other alloys
2 © ISO 2020 – All rights reserved
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ISO 15156-2:2020(E)
1)
NACE TM0177 , Laboratory testing of metals for resistance to sulfide stress cracking and stress corrosion
cracking in H S environments
2
NACE TM0284, Evaluation of pipeline and pressure vessel steels for resistance to hydrogen-induced cracking
NACE TM0316, Four-point bend testing of materials for oil and gas applications
2)
SAE AMS-2430 , Shot Peening
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 15156-1 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
Brinell hardness
HBW
hardness value of a material measured normally using a 10 mm diameter tungsten carbide ball indenter
with a force of 29,42 kN
Note 1 to entry: The measurement shall be in accordance with the ISO 6506 series. Here, ASTM E10 is equivalent
to ISO 6506-1.
3.2
bubble-point pressure
p
B
pressure under which gas bubbles form in a liquid at a particular operating temperature
Note 1 to entry: See C.2.
3.3
burnishing
process of smoothing surfaces using frictional contact between the material and some other hard
pieces of material, such as hardened steel balls
3.4
casting
metal that is obtained at or near its finished shape by the solidification of molten metal in a mould
3.5
cast iron
iron-carbon alloy containing approximately 2 % to 4 % mass fraction carbon
3.5.1
grey cast iron
cast iron that displays a grey fracture surface due to the presence of flake graphite
3.5.2
white cast iron
cast iron that displays a white fracture surface due to the presence of cementite
1) www .nace .org
2) www .sae .org
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ISO 15156-2:2020(E)
3.5.3
malleable iron
white cast iron that is thermally treated to convert most or all of the cementite to graphite (temper carbon)
3.5.4
ductile iron
nodular cast iron
cast iron that has been treated while molten with an element (usually magnesium or cerium) that
spheroidizes the graphite
3.6
cementite
microstructural constituent of steels composed principally of iron carbide (Fe C)
3
3.7
cold deforming
cold forging
cold forming
cold working
deforming metal plastically under conditions of temperature and strain rate that induce strain-
hardening, usually, but not necessarily, conducted at room temperature
3.8
fitness-for-purpose
suitability for use under the expected service conditions
3.9
free-machining steel
steel to which elements such as sulfur, selenium and lead have been added intentionally to improve
machineability
3.10
lower critical temperature
temperature of a ferrous metal at which austenite begins to form during heating or at which the
transformation of austenite is completed during cooling
3.11
nitriding
case-hardening process in which nitrogen is introduced into the surface of metallic materials (most
commonly ferrous alloys)
EXAMPLE Liquid nitriding, gas nitriding, ion nitriding and plasma nitriding.
3.12
normalize
heating a ferrous metal to a suitable temperature above the transformation range (austenitizing),
holding at temperature for a suitable time and then cooling in still air (or protective atmosphere) to a
temperature substantially below the transformation range
3.13
plastically deformed
permanently deformed by stressing beyond the limit of elasticity, i.e. the limit of proportionality of
stress to strain
3.14
pressure-containing part
part whose failure to function as intended results in a release of retained fluid to the atmosphere
EXAMPLE Valve bodies, bonnets and stems.
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ISO 15156-2:2020(E)
3.15
quenched and tempered
quench hardened and then tempered
3.16
Rockwell C hardness
HRC
hardness value of a material measured using a Rockwell C diamond cone indenter with a force of 1 471 N
Note 1 to entry: The measurement shall be in accordance with the ISO 6508 series. Here, ASTM E18 is equivalent
to ISO 6508-1.
3.17
shot-peening
inducing compressive stresses in the surface layer of a material by bombarding it with a selected
medium (usually round steel shot) under controlled conditions
3.18
stress relief
heating a metal to a suitable temperature, holding at that temperature long enough to reduce residual
stresses, and then cooling slowly enough to minimize the development of new residual stresses
3.19
tempering
heat treatment by heating to a temperature below the lower critical temperature, for the purpose
of decreasing the hardness and increasing the toughness of hardened steel, hardened cast iron and,
sometimes, normalized steel
3.20
tensile strength
ultimate strength
ratio of maximum load to original cross-sectional area
Note 1 to entry: See ISO 6892-1.
3.21
test batch
group of items representing a production batch whose conformity with a specified requirement can be
determined by testing representative samples in accordance with a defined procedure
3.22
tubular component
cylindrical component (pipe) having a longitudinal hole, used in drilling/production operations for
conveying fluids
3.23
Vickers hardness
HV
hardness value of a material using a diamond pyramid indenter and one of a variety of possible
applied loads
Note 1 to entry: The measurement shall be in accordance with the ISO 6507 series. Here, ASTM E384 is equivalent
to ISO 6507-1.
3.24
weldment
portion of a component on which welding has been performed, including the weld metal, the heat-
affected zone, and the adjacent parent metal
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ISO 15156-2:2020(E)
3.25
weld metal
portion of a weldment that has been molten during welding
3.26
wrought
formed to a desired shape by working (rolling, extruding, forging, etc.), usually at an elevated
temperature
4 Symbols and abbreviated terms
AYS actual yield strength
CLR crack length ratio
CSR crack surface ratio
CTR crack thickness ratio
DCB double cantilever beam (test)
FPB four-point bend (test)
HBW Brinell hardness
HIC hydrogen-induced cracking
HRC Rockwell hardness (scale C)
HSC hydrogen stress cracking
OCTG oil country tubular goods, i.e. casing, tubing and drill pipe
p partial pressure of H S
2
HS
2
p partial pressure of CO
2
CO
2
R 0,2 % proof stress in accordance with ISO 6892-1
p0,2
SMYS specified minimum yield strength
SOHIC stress-oriented hydrogen-induced cracking
SSC sulfide stress cracking
SWC stepwise cracking
SZC soft-zone cracking
T temperature
UNS Unified Numbering System (from SAE-ASTM, Metals and alloys in the Unified Numbering System)
UT uniaxial tensile (test)
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ISO 15156-2:2020(E)
5 Purchasing information
5.1 The preparation of material purchasing specifications can require co-operation and exchange of
data between the equipment user, the equipment supplier and the material manufacturer to ensure that
the material purchased conforms with ISO 15156-1 and this document.
5.2 The following information shall be provided:
— preferred material types and/or grades (if known);
— equipment type (if known);
— reference to this document;
— acceptable bases for selection of materials for SSC resistance (see Clause 7);
— requirements for HIC resistance (see Clause 8).
5.3 The equipment user and the equipment supplier/material manufacturer may agree that carbon or
low-alloy steels other than those described and/or listed in Annex A may be selected subject to suitable
qualification testing in accordance with Annex B and ISO 15156-1. The qualification requirements may
be extended to include resistance to SOHIC and SZC.
If the purchaser intends to make use of such agreements, extensions and qualifications, the appropriate
additional information shall be clearly indicated in the materials purchasing specification. This
information may include
— requirements for SSC testing (see 7.1 and 7.2),
— service conditions for specific sour-service application, and
— other special requirements.
5.4 Annex C describes how to calculate the H S partial pressure and Annex D gives guidance on how to
2
determine the pH-value of a fluid.
5.5 The information required for material purchasing shall be entered on suitable data sheets.
Suggested formats are given in Annex E.
6 Factors affecting the behaviour of carbon and low alloy steels in H S-
2
containing environments
The behaviour of carbon and low-alloy steels in H S-containing environments is affected by complex
2
interactions of parameters, including the following:
a) chemical composition, method of manufacture, product form, strength, hardness of the material
and its local variations, amount of cold work, heat-treatment condition, microstructure,
microstructural uniformity, grain size and cleanliness of the material;
b) H S partial pressure or equivalent concentration in the water phase;
2
c) chloride ion concentration in the water phase;
d) acidity (pH) of the water phase;
e) presence of sulfur or other oxidants;
f) exposure to non-production fluids;
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ISO 15156-2:2020(E)
g) exposure temperature;
h) total tensile stress (applied plus residual);
i) exposure time.
These factors shall be considered when using this document for the selection of materials suitable for
environments containing H S in oil and gas production systems.
2
7 Qualification and selection of carbon and low-alloy steels with resistance to
SSC, SOHIC and SZC
7.1 Option 1 — Selection of SSC-resistant steels (and cast irons) using A.2
7.1.1 For p < 0,3 kPa (0,05 psi)
HS
2
The selection of materials for SSC resistance for p below 0,3 kPa (0,05 psi) is not considered in detail
HS
2
in this document. Normally, no special precautions are required for the selection of steels for use under
these conditions, nevertheless, highly susceptible steels can crack. Additional information on factors
affecting susceptibility of steels and attack by cracking mechanisms other than SSC is given in 7.2.1.
7.1.2 For p ≥ 0,3 kPa (0,05 psi)
HS
2
If the partial pressure of H S in the gas is equal to or greater than 0,3 kPa (0,05 psi), SSC-resistant steels
2
shall be selected using A.2.
NOTE 1 The steels described or listed in A.2 are considered resistant to SSC in oil and natural-gas production
and natural-gas treatment plants.
NOTE 2 Users concerned with the occurrence of SOHIC and/or SZC can refer to Option 2 (see 7.2.2).
NOTE 3 For HIC and SWC, see Clause 8.
7.2 Option 2 — Selection of
...
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 15156-2
ISO/TC 67
Petroleum and natural gas
Secretariat: NEN
industries — Materials for use in H S-
2
Voting begins on:
2020-06-19 containing environments in oil and
gas production —
Voting terminates on:
2020-09-11
Part 2:
Cracking-resistant carbon and low-
alloy steels, and the use of cast irons
Industries du pétrole et du gaz naturel — Matériaux pour utilisation
dans des environnements contenant de l'hydrogène sulfuré (H2S)
dans la production de pétrole et de gaz —
Partie 2: Aciers au carbone et aciers faiblement alliés résistants à la
fissuration, et utilisation de fontes
ISO/CEN PARALLEL PROCESSING
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 15156-2:2020(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
©
NATIONAL REGULATIONS. ISO 2020
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ISO/FDIS 15156-2:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/FDIS 15156-2:2020(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 3
4 Symbols and abbreviated terms . 6
5 Purchasing information . 6
6 Factors affecting the behaviour of carbon and low alloy steels in H S-containing
2
environments . 7
7 Qualification and selection of carbon and low-alloy steels with resistance to SSC,
SOHIC and SZC . 8
7.1 Option 1 — Selection of SSC-resistant steels (and cast irons) using A.2 . 8
7.1.1 For p < 0,3 kPa (0,05 psi) . 8
HS
2
7.1.2 For p ≥ 0,3 kPa (0,05 psi) . 8
HS
2
7.2 Option 2 — Selection of steels for specific sour-service applications or for ranges
of sour service . 8
7.2.1 Sulfide stress-cracking . 8
7.2.2 SOHIC and SZC .10
7.3 Hardness requirements .10
7.3.1 General.10
7.3.2 Parent metals .10
7.3.3 Welds .10
7.4 Other fabrication methods .16
8 Evaluation of carbon and low alloy steels for their resistance to HIC/SWC .16
9 Marking, labelling, and documentation .17
Annex A (normative) SSC-resistant carbon and low alloy steels (and requirements and
recommendations for the use of cast irons) .18
Annex B (normative) Qualification of carbon and low-alloy steels for H S service by
2
laboratory testing .27
Annex C (informative) Determination of H S partial pressure and use of alternative parameters .35
2
Annex D (informative) Recommendations for determining pH .40
Annex E (informative) Information that should be supplied for material purchasing .45
Bibliography .47
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ISO/FDIS 15156-2:2020(E)
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 documents 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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 67, Materials, equipment and offshore
structures for petroleum, petrochemical and natural gas industries, in collaboration with the European
Committee for Standardization (CEN) Technical Committee CEN/TC 12, Materials, equipment and
offshore structures for petroleum, petrochemical and natural gas industries, in accordance with the
Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This fourth edition cancels and replaces the third edition (ISO 15156-2:2015), which has been
technically revised. The main changes compared to the previous edition are as follows:
— corrections of temperature conversion for welding (see A.2.1.4), vold deformation and stress relief
(see A.2.1.6), identification stamping (see A.2.1.9), tubulars and tubular components (see A.2.2.3.4),
compressor impellers (see A.2.3.3.2);
— title change from Shear rams to Rams in A.2.3.2.2;
— addition of C110 and changes the designation of C95 to R95 in Table A.3;
— reference change to NACE TM0316 in Table B.1;
— addition of reference to BS 8701 in B.4.3;
— changes and additions to Table B.3;
— modification of Annex C to include alternative parameters and expanded explanation for the use of
chemical activity and fugacity, and to provide some general guidance for the use of thermodynamic
modeling for the determination of environmental severity.
A list of all parts in the ISO 15156 series can be found on the ISO website.
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.
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ISO/FDIS 15156-2:2020(E)
Introduction
The consequences of sudden failures of metallic oil and gas field components, associated with their
exposure to H S-containing production fluids, led to the preparation of the first edition of NACE MR0175,
2
which was published in 1975 by the National Association of Corrosion Engineers, now known as NACE
International.
The original and subsequent editions of NACE MR0175 established limits of H S partial pressure above
2
which precautions against sulfide stress-cracking (SSC) were always considered necessary. They
also provided guidance for the selection and specification of SSC-resistant materials when the H S
2
thresholds were exceeded. In more recent editions, NACE MR0175 has also provided application limits
for some corrosion-resistant alloys, in terms of environmental composition and pH, temperature and
H S partial pressures.
2
In separate developments, the European Federation of Corrosion issued EFC Publication 16 in 1995 and
EFC Publication 17 in 1996. These documents are generally complementary to those of NACE though
they differed in scope and detail.
In 2003, the publication of the ISO 15156-series and NACE MR0175/ISO 15156 was completed for the
first time. These technically identical documents utilized the above sources to provide requirements
and recommendations for materials qualification and selection for application in environments
containing wet H S in oil and gas production systems. They are complemented by NACE TM0177 and
2
NACE TM0284 test methods.
The revision of this document, i.e. ISO 15156-2,involves a consolidation of all changes agreed
and published in the Technical Circular 1, ISO 15156-2:2015/Cir.1:2017, the Technical Circular 2,
ISO 15156-2:2015/Cir.2:2018 and the Technical Circular 3, ISO 15156-2:2015/Cir.3:2019, published by
the ISO 15156 series Maintenance Agency secretariat at DIN.
The changes were developed by and approved by the ballot of, representative groups from within
the oil and gas production industry. The great majority of these changes stem from issues raised by
document users. A description of the process by which these changes were approved can be found at
the ISO 15156 series maintenance website: www .iso .org/ iso15156maintenance.
When found necessary by oil and gas production industry experts, future interim changes to this
document will be processed in the same way and will lead to interim updates to this document in
the form of Technical Corrigenda or Technical Circulars. Document users should be aware that such
documents can exist and can impact the validity of the dated references in this document.
The ISO 15156 series Maintenance Agency at DIN was set up after approval by the ISO Technical
Management Board given in document 34/2007. This document describes the make up of the agency,
which includes experts from NACE, EFC and ISO/TC 67, and the process for approval of amendments.
It is available from the ISO 15156 series maintenance website and from the ISO/TC 67 Secretariat. The
website also provides access to related documents that provide more detail of the ISO 15156 series
maintenance activities.
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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 15156-2:2020(E)
Petroleum and natural gas industries — Materials
for use in H S-containing environments in oil and gas
2
production —
Part 2:
Cracking-resistant carbon and low-alloy steels, and the use
of cast irons
WARNING — Carbon and low-alloy steels and cast irons selected using this document are
resistant to cracking in defined H S-containing environments in oil and gas production but
2
not necessarily immune to cracking under all service conditions. It is the equipment user's
responsibility to select the carbon and low alloy steels and cast irons suitable for the intended
service.
1 Scope
This document gives requirements and recommendations for the selection and qualification of carbon
and low-alloy steels for service in equipment used in oil and natural gas production and natural gas
treatment plants in H S-containing environments, whose failure can pose a risk to the health and safety
2
of the public and personnel or to the environment. It can be applied to help to avoid costly corrosion
damage to the equipment itself. It supplements, but does not replace, the materials requirements of the
appropriate design codes, standards or regulations.
This document addresses the resistance of these steels to damage that can be caused by sulfide stress-
cracking (SSC) and the related phenomena of stress-oriented hydrogen-induced cracking (SOHIC) and
soft-zone cracking (SZC).
This document also addresses the resistance of these steels to hydrogen-induced cracking (HIC) and its
possible development into stepwise cracking (SWC).
This document is concerned only with cracking. Loss of material by general (mass loss) or localized
corrosion is not addressed.
Table 1 provides a non-exhaustive list of equipment to which this document is applicable, including
exclusions.
This document applies to the qualification and selection of materials for equipment designed and
constructed using load controlled design methods. For design utilizing strain-based design methods,
see ISO 15156-1:2020, Clause 5.
Annex A lists SSC-resistant carbon and low alloy steels, and A.2.4 includes requirements for the use of
cast irons.
This document is not necessarily suitable for application to equipment used in refining or downstream
processes and equipment.
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ISO/FDIS 15156-2:2020(E)
Table 1 — List of equipment
This document is applicable to materials used
Exclusions
for the following equipment
Drilling, well construction and well-servicing Equipment exposed only to drilling fluids of controlled
a
equipment composition
Drill bits
b
Blowout preventer (BOP) shear blades
Drilling riser systems
Work strings
c
Wireline and wireline equipment
Surface and intermediate casing
d
Wells, including subsurface equipment, gas lift Sucker rod pumps and sucker rods
equipment, wellheads and christmas trees
Electric submersible pumps
Other artificial lift equipment
Slips
Flow-lines, gathering lines, field facilities and field Crude oil storage and handling facilities operating at a
processing plants total absolute pressure below 0,45 MPa (65 psi)
Water-handling equipment Water-handling facilities operating at a total absolute
pressure below 0,45 MPa (65 psi)
Water injection and water disposal equipment
Natural gas treatment plants —
Transportation pipelines for liquids, gases and Lines handling gas prepared for general commercial
multiphase fluids and domestic use
For all equipment above Components loaded only in compression
a
See A.2.3.2.3 for more information.
b
See A.2.3.2.1 for more information.
c
Wireline lubricators and lubricator connecting devices are not excluded.
d
For sucker rod pumps and sucker rods, reference can be made to NACE MR0176.
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 6506 (all parts), Metallic materials — Brinell hardness test
ISO 6507 (all parts), Metallic materials — Vickers hardness test
ISO 6508 (all parts), Metallic materials — Rockwell hardness test
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
ISO 10423, Petroleum and natural gas industries — Drilling and production equipment — Wellhead and
christmas tree equipment
ISO 15156-1:2020, Petroleum and natural gas industries — Materials for use in H S-containing
2
environments in oil and gas production — Part 1: General principles for selection of cracking-resistant
materials
ISO 15156-3, Petroleum and natural gas industries — Materials for use in H2S-containing environments in
oil and gas production — Part 3: Cracking-resistant CRAs (corrosion-resistant alloys) and other alloys
2 © ISO 2020 – All rights reserved
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ISO/FDIS 15156-2:2020(E)
1)
NACE TM0177 , Laboratory testing of metals for resistance to sulfide stress cracking and stress corrosion
cracking in H S environments
2
NACE TM0284, Evaluation of pipeline and pressure vessel steels for resistance to hydrogen-induced cracking
NACE TM0316, Four-point bend testing of materials for oil and gas applications
2)
SAE AMS-2430 , Shot Peening
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 15156-1 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
Brinell hardness
HBW
hardness value of a material measured normally using a 10 mm diameter tungsten carbide ball indenter
with a force of 29,42 kN
Note 1 to entry: The measurement shall be in accordance with the ISO 6506 series. Here, ASTM E10 is equivalent
to ISO 6506-1.
3.2
bubble-point pressure
p
B
pressure under which gas bubbles form in a liquid at a particular operating temperature
Note 1 to entry: See C.2.
3.3
burnishing
process of smoothing surfaces using frictional contact between the material and some other hard
pieces of material, such as hardened steel balls
3.4
casting
metal that is obtained at or near its finished shape by the solidification of molten metal in a mould
3.5
cast iron
iron-carbon alloy containing approximately 2 % to 4 % mass fraction carbon
3.5.1
grey cast iron
cast iron that displays a grey fracture surface due to the presence of flake graphite
3.5.2
white cast iron
cast iron that displays a white fracture surface due to the presence of cementite
1) www .nace .org
2) www .sae .org
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ISO/FDIS 15156-2:2020(E)
3.5.3
malleable iron
white cast iron that is thermally treated to convert most or all of the cementite to graphite (temper carbon)
3.5.4
ductile iron
nodular cast iron
cast iron that has been treated while molten with an element (usually magnesium or cerium) that
spheroidizes the graphite
3.6
cementite
microstructural constituent of steels composed principally of iron carbide (Fe C)
3
3.7
cold deforming
cold forging
cold forming
cold working
deforming metal plastically under conditions of temperature and strain rate that induce strain-
hardening, usually, but not necessarily, conducted at room temperature
3.8
fitness-for-purpose
suitability for use under the expected service conditions
3.9
free-machining steel
steel to which elements such as sulfur, selenium and lead have been added intentionally to improve
machineability
3.10
lower critical temperature
temperature of a ferrous metal at which austenite begins to form during heating or at which the
transformation of austenite is completed during cooling
3.11
nitriding
case-hardening process in which nitrogen is introduced into the surface of metallic materials (most
commonly ferrous alloys)
EXAMPLE Liquid nitriding, gas nitriding, ion nitriding and plasma nitriding.
3.12
normalize
heating a ferrous metal to a suitable temperature above the transformation range (austenitizing),
holding at temperature for a suitable time and then cooling in still air (or protective atmosphere) to a
temperature substantially below the transformation range
3.13
plastically deformed
permanently deformed by stressing beyond the limit of elasticity, i.e. the limit of proportionality of
stress to strain
3.14
pressure-containing part
part whose failure to function as intended results in a release of retained fluid to the atmosphere
EXAMPLE Valve bodies, bonnets and stems.
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ISO/FDIS 15156-2:2020(E)
3.15
quenched and tempered
quench hardened and then tempered
3.16
Rockwell C hardness
HRC
hardness value of a material measured using a Rockwell C diamond cone indenter with a force of 1 471 N
Note 1 to entry: The measurement shall be in accordance with the ISO 6508 series. Here, ASTM E18 is equivalent
to ISO 6508-1.
3.17
shot-peening
inducing compressive stresses in the surface layer of a material by bombarding it with a selected
medium (usually round steel shot) under controlled conditions
3.18
stress relief
heating a metal to a suitable temperature, holding at that temperature long enough to reduce residual
stresses, and then cooling slowly enough to minimize the development of new residual stresses
3.19
tempering
heat treatment by heating to a temperature below the lower critical temperature, for the purpose
of decreasing the hardness and increasing the toughness of hardened steel, hardened cast iron and,
sometimes, normalized steel
3.20
tensile strength
ultimate strength
ratio of maximum load to original cross-sectional area
Note 1 to entry: See ISO 6892-1.
3.21
test batch
group of items representing a production batch whose conformity with a specified requirement can be
determined by testing representative samples in accordance with a defined procedure
3.22
tubular component
cylindrical component (pipe) having a longitudinal hole, used in drilling/production operations for
conveying fluids
3.23
Vickers hardness
HV
hardness value of a material using a diamond pyramid indenter and one of a variety of possible
applied loads
Note 1 to entry: The measurement shall be in accordance with the ISO 6507 series. Here, ASTM E384 is equivalent
to ISO 6507-1.
3.24
weldment
portion of a component on which welding has been performed, including the weld metal, the heat-
affected zone, and the adjacent parent metal
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ISO/FDIS 15156-2:2020(E)
3.25
weld metal
portion of a weldment that has been molten during welding
3.26
wrought
formed to a desired shape by working (rolling, extruding, forging, etc.), usually at an elevated
temperature
4 Symbols and abbreviated terms
AYS actual yield strength
CLR crack length ratio
CSR crack surface ratio
CTR crack thickness ratio
DCB double cantilever beam (test)
FPB four-point bend (test)
HBW Brinell hardness
HIC hydrogen-induced cracking
HRC Rockwell hardness (scale C)
HSC hydrogen stress cracking
OCTG oil country tubular goods, i.e. casing, tubing and drill pipe
p partial pressure of H S
2
HS
2
R 0,2 % proof stress in accordance with ISO 6892-1
p0,2
SMYS specified minimum yield strength
SOHIC stress-oriented hydrogen-induced cracking
SSC sulfide stress-cracking
SWC stepwise cracking
SZC soft-zone cracking
T temperature
UNS Unified Numbering System (from SAE-ASTM, Metals and alloys in the Unified Numbering System)
UT uniaxial tensile (test)
5 Purchasing information
5.1 The preparation of material purchasing specifications can require co-operation and exchange of
data between the equipment user, the equipment supplier and the material manufacturer to ensure that
the material purchased conforms with ISO 15156-1 and this document.
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ISO/FDIS 15156-2:2020(E)
5.2 The following information shall be provided:
— preferred material types and/or grades (if known);
— equipment type (if known);
— reference to this document;
— acceptable bases for selection of materials for SSC resistance (see Clause 7);
— requirements for HIC resistance (see Clause 8).
5.3 The equipment user and the equipment supplier/material manufacturer may agree that carbon or
low-alloy steels other than those described and/or listed in Annex A may be selected subject to suitable
qualification testing in accordance with Annex B and ISO 15156-1. The qualification requirements may
be extended to include resistance to SOHIC and SZC.
If the purchaser intends to make use of such agreements, extensions and qualifications, the appropriate
additional information shall be clearly indicated in the materials purchasing specification. This
information may include
— requirements for SSC testing (see 7.1 and 7.2),
— service conditions for specific sour-service application, and
— other special requirements.
5.4 Annex C describes how to calculate the H S partial pressure and Annex D gives guidance on how to
2
determine the pH-value of a fluid.
5.5 The information required for material purchasing shall be entered on suitable data sheets.
Suggested formats are given in Annex E.
6 Factors affecting the behaviour of carbon and low alloy steels in H S-
2
containing environments
The behaviour of carbon and low-alloy steels in H S-containing environments is affected by complex
2
interactions of parameters, including the following:
a) chemical composition, method of manufacture, product form, strength, hardness of the material
and its local variations, amount of cold work, heat-treatment condition, microstructure,
microstructural uniformity, grain size and cleanliness of the material;
b) H S partial pressure or equivalent concentration in the water phase;
2
c) chloride ion concentration in the water phase;
d) acidity (pH) of the water phase;
e) presence of sulfur or other oxidants;
f) exposure to non-production fluids;
g) exposure temperature;
h) total tensile stress (applied plus residual);
i) exposure time.
These factors shall be considered when using this document for the selection of materials suitable for
environments containing H S in oil and gas production systems.
2
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ISO/FDIS 15156-2:2020(E)
7 Qualification and selection of carbon and low-alloy steels with resistance to
SSC, SOHIC and SZC
7.1 Option 1 — Selection of SSC-resistant steels (and cast irons) using A.2
7.1.1 For p < 0,3 kPa (0,05 psi)
HS
2
The selection of materials for SSC resistance for p below 0,3 kPa (0,05 psi) is not considered in detail
HS
2
in this document. Normally, no special precautions are required for the selection of steels for use under
these conditions, nevertheless, highly susceptible steels can cra
...
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