EN ISO 17781:2017

Petroleum, petrochemical and natural gas industries - Test methods for quality control of microstructure of ferritic/austenitic (duplex) stainless steels (ISO 17781:2017)

ISO 17781:2017 specifies quality control testing methods and test conditions for the characterization of microstructure in relation to relevant properties in ferritic/austenitic (duplex) stainless steel components supplied in the solution annealed condition and fabrication welds in the as welded condition.
ISO 17781:2017 supplements the relevant product and fabrication standards with respect to destructive testing methods including sampling of test specimens, test conditions and test acceptance criteria to show freedom from deleterious intermetallic phases and precipitates in duplex stainless steels. In addition, this document specifies the documentation of testing and test results by the testing laboratory.
NOTE 1       This document is based upon experience with duplex stainless steels in offshore oil and gas industry applications including topside and subsea hydrocarbon service, sea water service, as well as structural use.
NOTE 2       The austenite spacing is relevant to the susceptibility of duplex stainless steels to hydrogen-induced stress cracking (HISC) in subsea applications where cathodic protection is applied. This falls outside the scope of this document. Reference is made to DNV/GL RP-F112[4].

Erdöl-, petrochemische und Erdgasindustrie - Prüfverfahren für die Qualitätslenkung von Mikrostrukturen von ferritisch/austenitisch nichtrostenden Duplexstählen (ISO 17781:2017)

Industries du pétrole, de la pétrochimie et du gaz naturel - Méthodes d'essai pour le contrôle de la qualité de la microstructure des aciers inoxydables austénitiques/ferritiques (duplex) (ISO 17781:2017)

ISO 17781:2017 spécifie les méthodes et les conditions d'essai de contrôle de la qualité pour caractériser la microstructure par rapport aux propriétés pertinentes des composants en acier inoxydable ferritique/austénitique (duplex) fournis à l'état recuit et les soudures de fabrication à l'état brut de soudage.
ISO 17781:2017 complète les normes de fabrication du produit concerné par rapport aux méthodes d'essais destructifs, y compris le prélèvement des éprouvettes, les conditions d'essai et les critères d'acceptation des essais, pour démontrer l'absence de phases intermétalliques préjudiciables et de précipités dans les aciers inoxydables duplex. De plus, le présent document précise la documentation des essais et des résultats des essais par le laboratoire d'essai.
NOTE 1    Le présent document se fonde sur l'expérience acquise avec des aciers inoxydables duplex dans des applications de plates-formes d'extraction en mer de pétrole et de gaz, y compris dans le cadre d'un fonctionnement en milieu hydrocarbure sous-marin ou en surface ou en service dans l'eau de mer ou pour une utilisation structurelle.
NOTE 2    L'espacement austénitique est pertinent pour la sensibilité des aciers inoxydables duplex à la fissuration par contrainte induite par l'hydrogène (HISC) dans les applications sous-marines en présence d'une protection cathodique. Cela ne relève pas du domaine d'application du présent document. Cela relève du domaine d'application du DNV/GL RP-F112[4].

Petrokemična industrija ter industrija za predelavo nafte in zemeljskega plina - Preskusne metode za kontrolo kakovosti mikrostrukture avstenitno-feritnega (dupleksnega) nerjavnega jekla (ISO 17781:2017)

Ta dokument določa preskusne metode za kontrolo kakovosti in preskusne pogoje za karakterizacijo mikrostrukture glede na ustrezne lastnosti komponent iz avstenitno-feritnega (dupleksnega) nerjavnega jekla, ki so dobavljene v žarjenem stanju, in proizvodnih zvarov v varjenem stanju.
Ta dokument dopolnjuje ustrezne standarde proizvodov in izdelave v zvezi s porušitvenimi preskusnimi metodami, vključno z vzorčenjem, preskusnimi pogoji in merili sprejemljivosti preskusa, za dokazovanje neprisotnosti zdravju škodljivih intermetalnih faz in izločkov v dupleksnih nerjavnih jeklih. Dokument poleg tega določa dokumentacijo za preskušanje in rezultate preskusa iz laboratorija za preskušanje.
OPOMBA 1: Ta dokument temelji na izkušnjah z dupleksnimi nerjavnimi jekli, ki se uporabljajo v industriji za predelavo nafte in zemeljskega plina, med drugim v sistemih za rokovanje z ogljikovodiki, sistemih za rokovanje z morsko vodo in uporabo v strukturah na palubi in pod morsko gladino.
OPOMBA 2: Avstenitni razmak je pomemben za določanje občutljivosti dupleksnega nerjavnega jekla na inducirano vodikovo napetostno pokanje (HISC) pri uporabi pod vodo, kjer se uporablja katodna zaščita. Slednje ne spada na področje uporabe tega dokumenta. Dokument se sklicuje na dokument DNV/GL RP-F112[4].

General Information

• Status: Published
• Publication Date: 29-Aug-2017
• Withdrawal Date: 27-Feb-2018
• ICS: 75.180.01 - Equipment for petroleum and natural gas industries in general
• ICS: 77.140.20 - Stainless steels
• Technical Committee: CEN/TC 12 - Materials, equipment and offshore structures for petroleum and natural gas industries
• Drafting Committee: CEN/TC 12 - Materials, equipment and offshore structures for petroleum and natural gas industries
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 30-Aug-2017
• Completion Date: 30-Aug-2017
• Ref Project: SIST EN ISO 17781:2017 - Petroleum, petrochemical and natural gas industries - Test methods for quality control of microstructure of austenitic/ferritic (duplex) stainless steel (ISO 17781:2017)

Overview

EN ISO 17781:2017 - Petroleum, petrochemical and natural gas industries - Test methods for quality control of microstructure of ferritic/austenitic (duplex) stainless steels - specifies standardized destructive test methods, sampling, test conditions and reporting for assessing the microstructure of duplex stainless steels. It applies to components supplied in the solution‑annealed condition and to fabrication welds in the as‑welded condition. The standard is intended to demonstrate freedom from deleterious intermetallic phases and precipitates that can reduce corrosion resistance and toughness in oil & gas service.

Key Topics

• Microstructural examination: specimen preparation, etching and metallographic evaluation to detect phases and precipitates.
• Ferrite content measurement: standardized methods and reporting to verify phase balance (typical duplex ferrite fraction ranges cited in the standard).
• Destructive tests covered: Charpy V‑notch impact testing, corrosion testing and other techniques to show material fitness for service.
• Sampling and specimen selection: procedures for casting test blocks and weld sampling to ensure representative testing.
• Acceptance criteria and documentation: criteria to demonstrate absence of harmful intermetallic phases (e.g., sigma σ, chi χ) and required test records from the testing laboratory.
• Relevant metallurgical context: duplex steels are high‑chromium (≈19–33 %) alloys with 35–65 % ferrite in solution‑annealed products; susceptibility to precipitation and embrittlement occurs in temperature ranges noted in the standard (intermetallic phases ~590 °C–1000 °C; alpha‑prime decomposition ~300 °C–540 °C).

Applications

• Quality control for offshore and onshore oil & gas equipment (topside and subsea), seawater service components and structural elements where duplex stainless steels are specified.
• Used by manufacturers, fabricators and welding contractors to qualify product batches and welding procedures.
• Employed by testing laboratories, inspection and QC engineers, purchasers and certification bodies to ensure delivered components meet microstructural integrity requirements and to document compliance in procurement and fabrication workflows.

Related Standards (examples)

• ISO 148‑1 - Charpy impact test methods
• ISO 15614‑1 - Welding procedure qualification
• ASTM A1084 - Detecting detrimental phases in lean duplex stainless steels
• ASTM E3, E562 - Metallographic specimen preparation and analysis
• DNV/GL RP‑F112 - Guidance on austenite spacing and hydrogen‑induced stress cracking (HISC) - noted as outside EN ISO 17781’s scope

EN ISO 17781:2017 is a practical reference for ensuring duplex stainless steel components perform reliably in demanding petroleum, petrochemical and natural gas environments by standardizing how microstructure is tested, evaluated and documented.

Standards Content (Sample)

SLOVENSKI STANDARD
01-november-2017
3HWURNHPLþQDLQGXVWULMDWHULQGXVWULMD]DSUHGHODYRQDIWHLQ]HPHOMVNHJDSOLQD
3UHVNXVQHPHWRGH]DNRQWURORNDNRYRVWLPLNURVWUXNWXUHDYVWHQLWQRIHULWQHJD
GXSOHNVQHJDQHUMDYQHJDMHNOD,62
Petroleum, petrochemical and natural gas industries - Test methods for quality control of
microstructure of austenitic/ferritic (duplex) stainless steel (ISO 17781:2017)
Erdöl-, petrochemische und Erdgasindustrie - Werkstofftestanforderungen für
nichtrostenden Duplexstahl (ISO 17781:2017)
Industries du pétrole, de la pétrochimie et du gaz naturel - Méthodes d'essai de contrôle
de la qualité de la microstructure des aciers inoxydables (duplex)
austénitiques/ferritiques (ISO 17781:2017)
Ta slovenski standard je istoveten z: EN ISO 17781:2017
ICS:
75.180.01 Oprema za industrijo nafte in Equipment for petroleum and
zemeljskega plina na splošno natural gas industries in
general
77.140.20 Visokokakovostna jekla Stainless steels
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 17781
EUROPEAN STANDARD
NORME EUROPÉENNE
August 2017
EUROPÄISCHE NORM
ICS 75.180.01
English Version
Petroleum, petrochemical and natural gas industries - Test
methods for quality control of microstructure of
ferritic/austenitic (duplex) stainless steels (ISO
17781:2017)
Industries du pétrole, de la pétrochimie et du gaz Erdöl-, petrochemische und Erdgasindustrie -
naturel - Méthodes d'essai de contrôle de la qualité de Prüfverfahren für die Qualitätslenkung von
la microstructure des aciers inoxydables (duplex) Microstrukturen von austenitisch/ferritisch
austénitiques/ferritiques (ISO 17781:2017) nichtrostendem Duplexstahl (ISO 17781:2017)
This European Standard was approved by CEN on 1 July 2017.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

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

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 17781:2017 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
European foreword
This document (EN ISO 17781:2017) has been prepared by Technical Committee ISO/TC 67 “Materials,
equipment and offshore structures for petroleum, petrochemical and natural gas industries” in
collaboration with Technical Committee CEN/TC 12 “Materials, equipment and offshore structures for
petroleum, petrochemical and natural gas industries” the secretariat of which is held by NEN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by February 2018, and conflicting national standards
shall be withdrawn at the latest by February 2018.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 17781:2017 has been approved by CEN as EN ISO 17781:2017 without any modification.

INTERNATIONAL ISO
STANDARD 17781
First edition
2017-07
Petroleum, petrochemical and
natural gas industries — Test
methods for quality control of
microstructure of ferritic/austenitic
(duplex) stainless steels
Industries du pétrole, de la pétrochimie et du gaz naturel — Méthodes
d’essai de contrôle de la qualité de la microstructure des aciers
inoxydables (duplex) austénitiques/ferritiques
Reference number
ISO 17781:2017(E)
©
ISO 2017
ISO 17781:2017(E)
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2017 – All rights reserved

ISO 17781:2017(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 2
3.1 Terms and definitions . 2
3.2 Abbreviated terms . 3
4 Sampling of test specimens . 4
4.1 General . 4
4.2 Casting test blocks. 6
4.3 Welds in the as welded condition . 6
5 Test methods . 7
5.1 General . 7
5.2 Microstructural examination . 7
5.2.1 General. 7
5.2.2 Preparation of specimen . 7
5.2.3 Etching of specimens . . 7
5.2.4 Microstructural evaluation of test specimens . 8
5.3 Ferrite content measurement .10
5.3.1 Test standard and conditions .10
5.3.2 Acceptance criteria .11
5.3.3 Reporting .11
5.4 Charpy V-notch impact toughness test .11
5.4.1 Test standard and conditions .11
5.4.2 Acceptance criteria .11
5.4.3 Reporting .12
5.5 Corrosion test .12
5.5.1 Test standard and conditions .12
5.5.2 Preparation of test specimens .13
5.5.3 Acceptance criteria .13
5.5.4 Reporting .13
Annex A (informative) Chemical compositions of duplex stainless steels .14
Annex B (informative) Preparation and etching for microstructural examination .16
Bibliography .18
ISO 17781:2017(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 on 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 the following
URL: w w w . i s o .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.
iv © ISO 2017 – All rights reserved

ISO 17781:2017(E)
Introduction
The aim of this document is to establish common test methods for quality control of microstructure of
ferritic/austenitic (duplex) stainless steels for the oil and gas industry, enabling the manufacturers to
apply the same test procedures for their clients.
Duplex stainless steels have a dual phase microstructure consisting of ferrite and austenite. Ideally,
these phases are present in equal proportions; although in alloys which are commercially available, the
ferrite phase volume fraction can vary between 35 % and 65 % for products in the solution annealed
condition. They are characterized by high-chromium (19 % to 33 %) and low-nickel contents compared
with austenitic stainless steels.
Duplex stainless steels are prone to precipitation of intermetallic phases, carbides and/or nitrides
possibly causing embrittlement and reduced corrosion resistance. The formation of intermetallic
phases such as Sigma, σ, and Chi, χ, occurs depending on exposure time in the approximate temperature
range 590 °C to 1 000 °C (1 094 °F to 1 832 °F) and decomposition of ferrite to Alpha Prime occurs in the
range 300 °C to 540 °C (572 °F to 1 004 °F).
The microstructure of components or fabrication welds is affected by amongst others the thermal-
mechanical history associated with hot working, solution annealing and with subsequent forming
and welding. The destructive test methods with acceptance criteria specified herein are considered
relevant to verify that exposure time at above stated temperature ranges have been within acceptable
limits and to ensure that desired corrosion resistance and mechanical properties are obtained in final
products.
INTERNATIONAL STANDARD ISO 17781:2017(E)
Petroleum, petrochemical and natural gas industries —
Test methods for quality control of microstructure of
ferritic/austenitic (duplex) stainless steels
1 Scope
This document specifies quality control testing methods and test conditions for the characterization
of microstructure in relation to relevant properties in ferritic/austenitic (duplex) stainless steel
components supplied in the solution annealed condition and fabrication welds in the as welded
condition.
This document supplements the relevant product and fabrication standards with respect to destructive
testing methods including sampling of test specimens, test conditions and test acceptance criteria to
show freedom from deleterious intermetallic phases and precipitates in duplex stainless steels. In
addition, this document specifies the documentation of testing and test results by the testing laboratory.
NOTE 1 This document is based upon experience with duplex stainless steels in offshore oil and gas industry
applications including topside and subsea hydrocarbon service, sea water service, as well as structural use.
NOTE 2 The austenite spacing is relevant to the susceptibility of duplex stainless steels to hydrogen-induced
stress cracking (HISC) in subsea applications where cathodic protection is applied. This falls outside the scope of
[4]
this document. Reference is made to DNV/GL RP-F112 .
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 148-1, Metallic materials — Charpy pendulum impact test — Part 1: Test method
1)
ISO 15614-1 , Specification and qualification of welding procedures for metallic materials — Welding
procedure test — Part 1: Arc and gas welding of steels and arc welding of nickel and nickel alloys)
ASTM A 370, Standard test methods and definitions for mechanical testing of steel products
ASTM A 1058, Standard test methods and definitions for mechanical testing of steel products — Metric
ASTM A 1084, Standard test method for detecting detrimental phases in lean duplex austenitic/ferritic
stainless steels
ASTM E 3, Standard practice for preparation of metallographic specimens
ASTM E 562, Standard test method for determining volume fraction by systematic manual point count
ASTM E 1245, Standard practice for determining the inclusion or second-phase constituent content of
metals by automatic image analysis
ASTM G 48, Standard test methods for pitting and crevice corrosion resistance of stainless steels and
related alloys by use of ferric chloride solution
1)  For the purpose of this document, the following documents are considered equivalent: ASME Boiler and
[2]
pressure vessel code, section IX Welding and brazing qualifications .
ISO 17781:2017(E)
3 Terms, definitions and abbreviated terms
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
NOTE For limitations in chemical composition of each specific material grade of duplex stainless steel,
reference is made to the appropriate product standards or UNS number. For nominal chemical composition of
duplex stainless steels and grouping of different types, used within this document, reference is made to Annex A.
3.1 Terms and definitions
3.1.1
centreline intermetallic stringer
group of intermetallic phases (3.1.4) aligned within the mid-thickness area due to alloy segregation
Note 1 to entry: They can be observed as both continuous and discontinuous precipitates.
3.1.2
fabrication
building of structures or equipment by cutting, bending, and assembling processes such as welding,
riveting, threaded fasteners or other joining methods
3.1.3
ferritic/austenitic (duplex) steel
stainless steel (3.1.8) with a high-chromium mass fraction (19 % to 33 %) with or without molybdenum
additions up to 5 %, and a nickel mass fraction intermediate to those of ferritic and austenitic
stainless steels
3.1.4
intermetallic phase
solid-state compounds, containing two or more metallic elements, whose ordered structure differs
from that of its constituents
Note 1 to entry: In duplex stainless steel, the most relevant phases are identified as σ-phase, χ-phase and R-phase.
3.1.5
lot
finite quantity of products from the same heat (or melt), same manufacturing process steps and same
heat treatment load
Note 1 to entry: For continuous and semi-continuous furnaces, the lot definition should comply with the
applicable product standards.
3.1.6
non-metallic precipitate
solid-state compounds, containing two or more elements, whose ordered structure differs from that of
its constituents
Note 1 to entry: In duplex stainless steel, the relevant non-metallic precipitates are chromium carbides and
nitrides.
2 © ISO 2017 – All rights reserved

ISO 17781:2017(E)
3.1.7
pitting resistance equivalent number
PREN
number indicating the resistance of stainless steel (3.1.8) to pitting corrosion related to chemical
composition and derived from one of the equations PREN = % Cr + 3,3 % Mo + 16 % N or PREN = % Cr +
3,3 × % (Mo + 0,5W) + 16 × % N (mass fraction)
Note 1 to entry: All PREN limits are absolute limits based upon the heat analysis. The calculated value is not to be
rounded.
3.1.8
stainless steel
steel with at least 10,5 % mass fraction or more chromium, possibly with other elements added to
secure special properties
3.1.9
type 20Cr duplex Group A
ferritic/austenitic stainless steel (3.1.8) alloys with 24,0 ≤ PREN < 28,0
3.1.10
type 20Cr duplex Group B
ferritic/austenitic stainless steel (3.1.8) alloys with 28,0 ≤ PREN < 30,0
3.1.11
type 22Cr duplex
ferritic/austenitic stainless steel (3.1.8) alloys with 30,0 ≤ PREN < 40,0 and Cr ≥ 19 % (mass fraction)
3.1.12
type 25Cr duplex
ferritic/austenitic stainless steel (3.1.8) alloys with 40,0 ≤ PREN < 48,0
3.1.13
type 27Cr duplex
ferritic/austenitic stainless steel (3.1.8) alloys with 48,0 ≤ PREN ≤ 55,0 and Cr ≤ 33,0 % (mass fraction)
3.2 Abbreviated terms
For the purposes of this document, the following abbreviated terms are used.
ASTM American society for testing and materials
CVN Charpy V-notch
HIP hot isostatically-pressed
NA not applicable
OD outside diameter
PREN pitting resistance equivalent number
QL quality level
T ruling section thickness
UNS unified numbering system
ISO 17781:2017(E)
4 Sampling of test specimens
4.1 General
The test samples shall be made from a sacrificial product or from a prolongation/extension of a
product in the final solution annealed condition with location of test specimens as defined in Table 1
representing the thickest product within the lot. Alternatively, a representative test block may be used
when agreed with the purchaser.
4 © ISO 2017 – All rights reserved

ISO 17781:2017(E)
Table 1 — Sampling of test specimens dependent of product
Product
a
Product Test sample Test method Test direction Thickness location
dimension
Plates, and Prolongation of All CVN Transverse Mid-thickness
seamless tubes, the product
b
Corrosion, Transverse Full thickness
pipes and fit-
Microstructure
tings
Welded pipes Prolongation or All CVN Transverse Mid-thickness
and fittings welded exten-
c b
Corrosion , Transverse Full thickness
sion piece
Microstructure
Bars and long Prolongation OD or section CVN Longitudinal Mid-thickness
solid forgings thickness
b
Corrosion, Transverse Surface to centre
without weld <50 mm (2 in)
Microstructure
end
OD or section CVN Longitudinal 1/4 thickness
thickness
b
Corrosion, Transverse Surface to centre
≥50 mm (2 in)
Microstructure
d
Flanges and Sacrificial prod- All CVN Both longitudinal Mid-thickness
other hollow uct or prolonga- and tangential to weld end
contour shaped tion at weld end centre bore
forgings with
b
Corrosion, Longitudinal or Full thickness
weld end includ-
Microstructure tangential weld end
ing tees
HIP products Sacrificial prod- All CVN Any direction Mid-thickness
with weld end uct or prolonga- weld end
tion at weld end
b
Corrosion, Any direction Full thickness
with greatest
Microstructure weld end
wall thickness
HIP products Sacrificial prod- Section thick- CVN Any direction Mid-thickness
without weld uct or prolon- ness <50 mm
b
Corrosion, Any direction Surface to centre
b
end gation at cross (2 in)
Microstructure
section with
Section thick- CVN Any direction 1/4 thickness
greatest wall
ness ≥50 mm
b
thickness
Corrosion, Any direction Surface to centre
(2 in)
Microstructure
Castings Sacrificial Test block CVN Any direction Mid-thickness
product or test thickness Corrosion,
block (see 4.2) <50 mm (2 in) Microstructure
Test block CVN Any direction Within hatched
thickness Corrosion, area (see Figure 1)
≥50 mm (2 in) Microstructure
a
For definition of test directions, reference is made to ASTM A 370/ASTM A 1058.
b
For products with large sections, the corrosion test specimen shall be taken transverse to the longitudinal axis with
dimensions of approximately 6 mm × 25 mm (1⁄4 in × 1 in) by thickness. For very large sections, the thickness dimension of
the specimen can be cut so that one-half to two-thirds of the product thickness is tested.
c
For welded products, the test specimens for corrosion testing and microstructure examination shall include weld
metal and the heat affected zone of parent metal. For products with wall thickness exceeding 25 mm, more than one (1)
specimen can be taken to cover full thickness. In such a case, all specimens shall fulfil the specified criteria.
d
When flange body thickness <50 mm (2 in) or weld end OD ≤100 mm (4 in), test specimens may be taken from the
flange body mid-thickness in tangential direction.
For all products, the mid-length of the test specimens shall be located one T or minimum 50 mm
...