SIST EN ISO 15156-2:2004
(Main)Petroleum, petrochemical 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 (ISO 15156-2:2003)
Petroleum, petrochemical 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 (ISO 15156-2:2003)
Erdöl- und Erdgasindustrie - Werkstoffe für den Einsatz in H2S-haltiger Umgebung bei der Öl- und Gasgewinnung - Teil 2: Gegen Rissbildung beständige unlegierte und niedriglegierte Stähle und Gusseisen (ISO 15156-2:2003)
Dieser Teil von ISO 15156 nennt Anforderungen und gibt Empfehlungen für die Auswahl und Qualifizierung von unlegierten und niedriglegierten Stählen für den Einsatz in Einrichtungen der Öl- und Gasgewinnung und in Erdgasaufbereitungsanlagen im Bereich H2S-haltiger Umgebungen, deren Versagen ein mögliches Gesundheits- und Sicherheitsrisiko für die Allgemeinheit und das Personal oder für die Umwelt darstellt. Er kann angewendet werden zur Vermeidung kostspieliger Beschädigungen infolge von Korrosion der Anlage selbst. Er ergänzt, ersetzt aber nicht die in einschlägigen Berechnungscodes, Normen oder Regelwerken vorgegebenen Anforderungen an Werkstoffe.
Dieser Teil von ISO 15156 behandelt die Beständigkeit dieser Stähle gegen Schäden, die durch schwefelwasserstoffinduzierte Spannungsrisskorrosion (SSC) sowie die damit zusammenhängende spannungsorientierte wasserstoffinduzierte Rissbildung (SOHIC) und Weichzonenrissbildung (SZC) verursacht werden können.
Dieser Teil von ISO 15156 behandelt auch die Beständigkeit dieser Stähle gegen wasserstoffinduzierte Rissbildung (HIC) und die daraus entstehende mögliche Stufenrissbildung (SWC).
Dieser Teil von ISO 15156 bezieht sich nur auf die Rissbildung. Materialschwund auf Grund allgemeiner
(Gewichtsschwund) oder örtlicher Korrosion wird nicht angesprochen.
Tabelle 1 enthält als nicht erschöpfende Liste eine Übersicht von Ausrüstungen, die in den Anwendungsbereich von ISO 15156 fallen.
Tabelle 1 enthält auch eine Liste der Ausrüstungen, die unter den vorgegebenen Umständen vom Anwendungsbereich von ISO 15156 ausgenommen sein können.
Dieser Teil von ISO 15156 gilt für die Qualifizierung und Auswahl von Werkstoffen für Ausrüstungen, die unter Verwendung konventioneller Kriterien für die elastische Auslegung bemessen und gebaut wurden. Für Auslegungen, die auf Plastizitätskriterien (z. B. Verformung und Grenzzustände) beruhen, siehe ISO 15156-1, Abschnitt 5.
WARNHINWEIS: Nach diesem Teil von ISO 15156 ausgewählte unlegiert
Industries du pétrole, pétrochimiques et du gaz naturel - Matériaux pour utilisation dans des environnements contenant de l'hydrogene sulfuré (H2S) dans la production de pétrole et de gaz - Partie 2: Aciers au carbone et aciers faiblement alliés résistants a la fissuration, et utilisation de fontes (ISO 15156-2:2003)
Petroleum, petrochemical 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 (ISO 15156-2:2003)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 15156-2:2004
01-maj-2004
Petroleum, petrochemical 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 (ISO 15156-2:2003)
Petroleum, petrochemical 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 (ISO 15156-2:2003)
Erdöl- und Erdgasindustrie - Werkstoffe für den Einsatz in H2S-haltiger Umgebung bei
der Öl- und Gasgewinnung - Teil 2: Gegen Rissbildung beständige unlegierte und
niedriglegierte Stähle und Gusseisen (ISO 15156-2:2003)
Industries du pétrole, pétrochimiques et du gaz naturel - Matériaux pour utilisation dans
des environnements contenant de l'hydrogene sulfuré (H2S) dans la production de
pétrole et de gaz - Partie 2: Aciers au carbone et aciers faiblement alliés résistants a la
fissuration, et utilisation de fontes (ISO 15156-2:2003)
Ta slovenski standard je istoveten z: EN ISO 15156-2:2003
ICS:
75.180.10 Oprema za raziskovanje in Exploratory and extraction
odkopavanje equipment
77.060 Korozija kovin Corrosion of metals
SIST EN ISO 15156-2:2004 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST EN ISO 15156-2:2004
---------------------- Page: 2 ----------------------
SIST EN ISO 15156-2:2004
---------------------- Page: 3 ----------------------
SIST EN ISO 15156-2:2004
---------------------- Page: 4 ----------------------
SIST EN ISO 15156-2:2004
INTERNATIONAL ISO
STANDARD 15156-2
First edition
2003-12-15
Petroleum and natural gas industries —
Materials for use in H S-containing
2
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 15156-2:2003(E)
©
ISO 2003
---------------------- Page: 5 ----------------------
SIST EN ISO 15156-2:2004
ISO 15156-2:2003(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO 2003
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2003 — All rights reserved
---------------------- Page: 6 ----------------------
SIST EN ISO 15156-2:2004
ISO 15156-2:2003(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
7.2 Option 2: Selection of steels for specific sour service applications or for ranges of sour
service. 8
7.3 Hardness requirements. 10
7.4 Other fabrication methods . 16
8 Evaluation of carbon and low alloy steels for their resistance to HIC/SWC. 16
9 Marking. 16
Annex A (normative) SSC-resistant carbon and low alloy steels (and requirements and
recommendations for the use of cast irons). 17
Annex B (normative) Qualification of carbon and low alloy steels for H S service by laboratory
2
testing. 26
Annex C (informative) Determination of H S partial pressure . 34
2
Annex D (informative) Recommendations for determining pH. 36
Annex E (informative) Information to be supplied for material purchasing . 41
Bibliography . 43
© ISO 2003 — All rights reserved iii
---------------------- Page: 7 ----------------------
SIST EN ISO 15156-2:2004
ISO 15156-2:2003(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 15156-2 was prepared by Technical Committee ISO/TC 67, Materials, equipment and offshore strcutures
for petroleum and natural gas industries.
ISO 15156 consists of the following parts, under the general title Petroleum and natural gas industries —
Materials for use in H S-containing environments in oil and gas production:
2
Part 1: General principles for selection of cracking-resistant materials
Part 2: Cracking-resistant carbon and low alloy steels, and the use of cast irons
Part 3: Cracking-resistant CRAs (corrosion-resistant alloys) and other alloys
iv © ISO 2003 — All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 15156-2:2004
ISO 15156-2:2003(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, which was
2
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 which
2
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 thresholds were
2
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
2
pressures. NACE MR0175 is complemented by NACE TM0177-96 and NACE TM0284 test methods.
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 differ in
scope and detail.
This part of ISO 15156 utilizes 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
2
systems.
Changes will be incorporated into this part of ISO 15156 by amendment or revision in accordance with
Interpretation and maintenance of ISO 15156 by ISO/TC 67/WG 7, copies of which can be obtained from the
ISO/TC 67 Secretariat. Experts from both NACE and EFC are members of ISO/TC 67/WG 7.
© ISO 2003 — All rights reserved v
---------------------- Page: 9 ----------------------
SIST EN ISO 15156-2:2004
---------------------- Page: 10 ----------------------
SIST EN ISO 15156-2:2004
INTERNATIONAL STANDARD ISO 15156-2:2003(E)
Petroleum and natural gas industries — Materials for use in
H S-containing environments in oil and gas production —
2
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 part of ISO 15156 are
resistant to cracking in defined H S-containing environments in oil and gas production but not
2
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 part of ISO 15156 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 could pose a risk to the health and safety of the public
2
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 part of ISO 15156 addresses the resistance of these steels to damage that may be caused by sulfide
stress-cracking (SSC) and the related phenomena of stress-oriented hydrogen-induced cracking (SOHIC) and
soft-zone cracking (SZC).
This part of ISO 15156 also addresses the resistance of these steels to hydrogen-induced cracking (HIC) and
its possible development into stepwise cracking (SWC).
This part of ISO 15156 is only concerned 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 part of ISO 15156 is applicable, including
permitted exclusions.
This part of ISO 15156 applies to the qualification and selection of materials for equipment designed and
constructed using conventional elastic design criteria. For designs utilizing plastic criteria (e.g. strain-based
and limit-state designs), see ISO 15156-1:2001, 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 part of ISO 15156 is not necessarily suitable for application to equipment used in refining or downstream
processes and equipment.
© ISO 2003 — All rights reserved 1
---------------------- Page: 11 ----------------------
SIST EN ISO 15156-2:2004
ISO 15156-2:2003(E)
Table 1 — List of equipment
ISO 15156 is applicable to materials used
Permitted exclusions
for the following equipment
a
Drilling, well construction and well-servicing Equipment only exposed to drilling fluids of controlled composition
equipment
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 Crude oil storage and handling facilities operating at a total absolute
field processing plants 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)
Natural gas treatment plants
Transportation pipelines for liquids, gases and Lines handling gas prepared for general commercial and domestic use
multiphase fluids
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 permitted exclusions.
d
For sucker rod pumps and sucker rods, reference can be made to NACE MR0176.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 6506-1, Metallic materials — Brinell hardness test — Part 1: Test method
ISO 6507-1, Metallic materials — Vickers hardness test — Part 1: Test method
ISO 6508-1, Metallic materials — Rockwell hardness test — Part 1: Test method (scales A, B, C, D, E, F, G,
H, K, N, T)
ISO 6892, Metallic materials — Tensile testing at ambient temperature
ISO 10423, Petroleum and natural gas industries — Drilling and production equipment — Wellhead and
christmas tree equipment
ISO 15156-1:2001, Petroleum and natural gas industries — Materials for use in H S-containing environments
2
in oil and gas production — Part 1: General principles for selection of cracking-resistant materials
2 © ISO 2003 — All rights reserved
---------------------- Page: 12 ----------------------
SIST EN ISO 15156-2:2004
ISO 15156-2:2003(E)
1)
NACE TM0177-96 , 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
2)
EFC Publications Number 16 , Guidelines on materials requirements for carbon and low alloy steels for H S-
2
containing environments in oil and gas production
3)
SAE AMS-S-13165 , Shot peening of metal parts
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 15156-1 and the following apply.
3.1
Brinell hardness
HBW
hardness value, measured in accordance with ISO 6506-1, normally using a 10-mm diameter tungsten ball
and a force of 29,42 kN
3.2
bubble-point pressure
p
B
pressure under which gas bubbles will form in a liquid at a particular operating temperature
NOTE See C.2.
3.3
burnish
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 % 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) NACE International, P.O. Box 2183140, Houston, Texas 77218-8340, USA
2) European Federation of Corrosion, available from The Institute of Materials, 1 Carlton House Terrace, London SW1Y
5DB, UK [ISBN 0-901716-95-2]
3) Society of Automotive Engineers (SAE), 400 Commonwealth Drive, Warrendale, PA 15096-0001 USA
© ISO 2003 — All rights reserved 3
---------------------- Page: 13 ----------------------
SIST EN ISO 15156-2:2004
ISO 15156-2:2003(E)
3.5.3
malleable cast iron
white cast iron that is thermally treated to convert most or all of the cementite to graphite (temper carbon)
3.5.4
ductile cast 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 working
cold deforming
cold forging
cold forming
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)
EXAMPLES Liquid nitriding, gas nitriding, ion nitriding and plasma nitriding.
3.12
normalizing
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 parts
those parts whose failure to function as intended would result in a release of retained fluid to the atmosphere
NOTE Examples are valve bodies, bonnets and stems.
4 © ISO 2003 — All rights reserved
---------------------- Page: 14 ----------------------
SIST EN ISO 15156-2:2004
ISO 15156-2:2003(E)
3.15
quenched and tempered
quench hardened and then tempered
3.16
Rockwell C hardness
HRC
hardness value, measured in accordance with ISO 6508, obtained using a diamond cone indenter and a force
of 1 471 N
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 relieving
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 See ISO 6892.
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, measured in accordance with ISO 6507-1, obtained using a diamond pyramid indenter and
one of a variety of possible applied loads
3.24
weldment
that portion of a component on which welding has been performed, including the weld metal, the heat-affected
zone (HAZ), and the adjacent parent metal
3.25
weld metal
that portion of a weldment that has been molten during welding
© ISO 2003 — All rights reserved 5
---------------------- Page: 15 ----------------------
SIST EN ISO 15156-2:2004
ISO 15156-2:2003(E)
3.26
wrought metal
metal in the solid condition that is formed to a desired shape by working (rolling, extruding, forging, etc.),
usually at an elevated temperature
4 Symbols and abbreviated terms
For the purposes of this document, the abbreviated terms given in ISO 15156-1 and the following apply.
AYS actual yield strength
CLR crack length ratio
CR c-ring (test)
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
HV Vickers hardness
OCTG oil country tubular goods, i.e. casing, tubing and drill pipe
p partial pressure of H S
H S 2
2
R 0,2 % proof stress in accordance with ISO 6892
p0,2
SMYS specified minimum yield strength
SOHIC stress-oriented hydrogen-induced cracking
SSC sulfide stress-cracking
SWC stepwise cracking
SZC soft-zone cracking
UNS Unified Numbering System (from SAE-ASTM, Metals and alloys in the Unified Numbering System)
UT uniaxial tensile (test)
6 © ISO 2003 — All rights reserved
---------------------- Page: 16 ----------------------
SIST EN ISO 15156-2:2004
ISO 15156-2:2003(E)
5 Purchasing information
5.1 The preparation of material purchasing specifications might require co-operation and exchange of data
between the equipment user, the equipment supplier and the material manufacturer to ensure that the
material purchased complies with ISO 15156-1 and this part of ISO 15156.
5.2 The following information shall be provided:
preferred material types and/or grades (if known);
equipment type (if known);
reference to this part of ISO 15156;
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, 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-containing
2
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;
© ISO 2003 — All rights reserved 7
---------------------- Page: 17 ----------------------
SIST EN ISO 15156-2:2004
ISO 15156-2:2003(E)
g) exposure temperature;
h) total tensile stress (applied plus residual);
i) exposure time.
These factors shall be considered when using this part of ISO 15156 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)
H S
2
The selection of materials for SSC resistance for p below 0,3 kPa (0,05 psi) is not considered in detail in
H S
2
this part of ISO 15156. Normally, no special precautions are required for the selection of steels for use under
these conditions, nevertheless, highly susceptible steels can crack. Further 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 W 0,3 kPa (0,05 psi)
H S
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, refer to Clause 8.
7.2 Option 2: Selection of steels for specific sour service applications or for ranges of sour
service
7.2.1 Sulfide stress-cracking (SSC)
7.2.1.1 General
Option 2 allows the user to qualify and select materials for SSC resistance for specific sour service
applications or for ranges of sour service.
The use of Option 2 may require knowledge of both the in situ pH and the H S partial pressure and their
2
variations with time (see ISO 15156-1).
Option 2 facilitates the purchase of bulk materials, such as OCTG or line pipe, where the economic incentive
to use materials not described nor listed in Annex A outweighs the additional qualification and other costs that
might be incurred. Steels for other equipment may also be qualified. In some cases this will require agreement
between the supplier and the equipment user with respect to test and acceptance requirements. Such
agreements shall be documented.
Option 2 can also facilitate fitness-for-purpose evaluations of existing carbon or low alloy steel equipment
exposed to sour service conditions more severe than assumed in the current design.
8 © ISO 2003 — All rights reserved
---------------------- Page: 18 ----------------------
SIST EN ISO 15156-2:2004
ISO 15156-2:2003(E)
7.2.1.2 SSC Regions of environmental severity
The severity of the sour environment, determined in accordance with ISO 15156-1, with respect to SSC of a
carbon or low alloy steel shall be assessed using Figure 1.
Key
X H S partial pressure, kPa
2
Y in situ pH
0 Region 0
1 SSC Region 1
2 SSC Region 2
3 SSC Region 3
In defining the severity of the H S-containing environment, the possibility of exposure to unbuffered condensed aqueous
2
phases of low pH during upset operating conditions or downtime, or to acids used for well stimulation and/or the backflow
of stimulation acid, after reaction should be considered.
NOTE 1 The discontinuities in the figure below 0,3 kPa (0,05 psi) and above 1 MPa (150 psi) partial pressure H S
2
reflect uncertainty with respect to the measurement of H S partial pressure (low H S) and steel’s performance outside
2 2
these limits (both low and high H S).
2
NOTE 2 Guidance on the ca
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.