SIST EN 14870-4:2023

SLOVENSKI STANDARD
01-september-2023
Industrija za predelavo nafte in zemeljskega plina - Indukcijska cevna kolena,
fitingi in prirobnice za naftovodne transportne sisteme - 4. del: Tovarniško hladno
upognjena cevna kolena (ISO 15590-4:2019, spremenjen)
Petroleum and natural gas industries - Induction bends, fittings and flanges for pipeline
transportation systems - Part 4: Factory cold bends (ISO 15590-4:2019, modified)
Erdöl- und Erdgasindustrie - Induktionsbögen, Zubehörteile und Flansche für
Fernleitungen - Teil 4: Durch werkseitige Kaltverformung gefertigte Rohrbögen (ISO
15590-4:2019, modifiziert)
Industries du pétrole et du gaz naturel - Coudes d'induction, raccords et brides pour
systèmes de transport par conduites - Partie 4 : Coudes fabriqués à froid en usine (ISO
15590-4:2019, modifiée)
Ta slovenski standard je istoveten z: EN 14870-4:2023
ICS:
75.200 Oprema za skladiščenje Petroleum products and
nafte, naftnih proizvodov in natural gas handling
zemeljskega plina equipment
83.140.30 Polimerne cevi in fitingi za Plastics pipes and fittings for
snovi, ki niso tekočine non fluid use
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 14870-4
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2023
EUROPÄISCHE NORM
ICS 75.200
English Version
Petroleum and natural gas industries - Induction bends,
fittings and flanges for pipeline transportation systems -
Part 4: Factory cold bends (ISO 15590-4:2019, modified)
Industries du pétrole et du gaz naturel - Coudes Erdöl- und Erdgasindustrie - Induktionsbögen,
d'induction, raccords et brides pour systèmes de Zubehörteile und Flansche für Fernleitungen - Teil 4:
transport par conduites - Partie 4 : Coudes fabriqués à Durch werkseitige Kaltverformung gefertigte
froid en usine (ISO 15590-4:2019, modifiée) Rohrbögen (ISO 15590-4:2019, modifiziert)
This European Standard was approved by CEN on 10 April 2023.

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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 14870-4 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 8
4 Symbols and abbreviated terms . 11
4.1 Symbols . 11
4.2 Abbreviated terms . 11
5 General requirements . 12
5.1 Units of measurement . 12
5.2 Rounding . 12
5.3 Conformance to this document . 12
6 Designation of cold bends . 12
7 Design . 13
8 Information provided by the purchaser . 13
8.1 General information . 13
8.2 Additional information . 13
8.3 Information on the mother pipe . 14
9 Manufacturing . 15
9.1 Mother pipe . 15
9.2 Qualification test bend . 15
9.3 Production cold bending . 16
9.4 Post-bending heat treatment . 16
9.5 Forming and sizing after bending . 17
9.6 Strip/plate end welds . 17
9.7 Jointers and girth welds . 17
9.8 End preparation . 17
10 Testing and inspection . 17
10.1 General requirements . 17
10.2 Extent of testing and inspection . 19
10.2.1 Qualification test bend . 19
10.2.2 Production bends . 21
10.2.3 Production test bends . 21
10.3 Chemical composition . 21
10.4 Physical testing . 21
10.4.1 General. 21
10.4.2 Tensile testing . 22
10.4.3 Charpy V-notch impact testing . 22
10.4.4 Through-thickness hardness testing . 23
10.4.5 Surface hardness testing . 24
10.4.6 Metallographic examination . 24
10.4.7 Guided bend testing . 24
10.4.8 Flattening tests . 25
10.5 Non-destructive testing . 25
10.5.1 Visual inspection . 25
10.5.2 Weld seam testing . 26
10.5.3 Inspection of bend ends . 26
10.5.4 Magnetic particle testing or liquid-penetrant testing on the bend body . 26
10.5.5 Ultrasonic testing on the bend body . 26
10.5.6 Level of residual magnetism . 26
10.5.7 Repairs . 26
10.5.8 NDT personnel . 27
10.6 Dimensions . 27
10.7 Gauging . 30
10.8 Hydrostatic testing . 30
11 Inspection document . 30
12 Marking . 30
Annex A (normative) Manufacturing procedure specification . 32
A.1 General . 32
A.2 Manufacturing procedure specification . 32
Annex B (normative) PSL 2S cold bends ordered for sour service . 34
B.1 Introduction . 34
B.2 Additional information provided by the purchaser. 34
B.3 Manufacturing. 34
B.3.1 Manufacturing procedure. 34
B.3.2 Pipe manufacturing . 34
B.4 Testing and inspection. 34
B.4.1 Tensile properties . 34
B.4.2 HIC/SWC test . 35
B.4.3 SSC test . 35
B.4.4 Requirements . 36
B.4.5 Hardness test . 36
B.5 Hard spots . 36
B.6 Inspection . 37
B.7 Non-destructive inspection . 37
B.7.1 Laminar imperfections at the pipe ends . 37
B.7.2 Ultrasonic testing on the bend body . 37
B.7.3 Ultrasonic inspection of SAW seam welds . 37
B.7.4 Non-destructive inspection of HFW weld seams . 37
Bibliography . 38

European foreword
This document (EN 14870-4:2023) has been prepared by 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 and CYS.
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 December 2023, and conflicting national standards shall
be withdrawn at the latest by December 2023.
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.
A list of all parts in the EN 14870 series can be found on the CEN website.
The text of ISO 15590-4:2019 has been adopted by CEN/TC 12 with some modifications to exclude the
aspects that are covered by CEN/TC 234 “Gas infrastructure”. These modifications are indicated by a
vertical line in the left margin of the text.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,
Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the United
Kingdom.
Introduction
This document makes reference to line pipe and bends with delivery conditions based on ISO 3183.
This document contains additional requirements for special applications as follows:
— Manufacturing procedure specification (Annex A);
— PSL 2S cold bends ordered for sour service (Annex B).
The requirements of the annexes apply only where they are specified on the purchase order. This
document does not provide guidance on when it is necessary to specify the above supplementary
requirements defined in the annexes. It is the responsibility of the purchaser to specify, based upon the
intended use and design requirements, the supplementary requirements that will apply for a particular
purchase order.
Further or differing requirements can be needed for individual applications. This document is not
intended to inhibit a manufacturer from offering, or the purchaser from accepting, alternative equipment
or engineering solutions for the individual application. This can be particularly applicable where there is
innovative or developing technology. Where an alternative is offered, it is the responsibility of the
manufacturer to identify and provide details of any variations from this document.
ISO 15590-4:2019, developed within ISO/TC 67/SC 2, has been adopted as EN 14870-4:2023
(ISO 15590-4:2019, modified).
The scope of ISO/TC 67/SC 2 is pipeline transportation systems for the petroleum and natural gas
industries without exclusions. However, in CEN the scopes of CEN/TC 12 and CEN/TC 234 overlapped
until 1995. This scope overlap caused problems for the parallel procedure for the above-mentioned item.
The conflict in scope was resolved when both the CEN Technical Committees concerns and the CEN
Technical Board decided to amend the scope of CEN/TC 12 by explicitly excluding “on-land supply systems
used by the gas supply industry excluding gas infrastructure from the input of gas into the on-shore
transmission network up to the inlet connection of gas appliances”.
1 Scope
This document specifies the technical delivery conditions for bends made by the cold bending process for
bend with radii 5xOD or higher for use in pipeline transportation systems for the petroleum and natural
gas industries as defined in ISO 13623. Short radius factory cold bends should not be used for pipeline.
NOTE 1 ISO 13623 is modified adopted as EN 14161 to exclude on-land supply systems used by the European
gas supply industry from the input of gas into the on-land transmission network up to the inlet connection of gas
appliances.
This document also specifies the requirements for the manufacture of two product specification levels
(PSLs) of cold bends corresponding to product specification levels given for pipe in ISO 3183. This
document is applicable to cold bends made from seamless and welded pipe of unalloyed or low-alloy
steels.
NOTE 2 These are typically C-Mn steels or low-alloy steels that are appropriate for the corresponding level and
grade of line pipe in accordance with ISO 3183.
This document is not applicable to the selection of the cold bend product specification level. It is the
responsibility of the purchaser to specify the PSL, based upon the intended use and design requirements.
NOTE 3 See also ISO 3183:2012, Introduction.
This document is not applicable to field cold bends and pipeline bends made by other manufacturing
processes.
On-land supply systems used by the European gas supply industry from the input of gas into the on-land
transmission network up to the inlet connection of gas appliances are excluded from the scope of this
document.
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.
EN 10204, Metallic products — Types of inspection documents
ISO 80000-1:2009, Quantities and units — Part 1: General
ISO 148-1, Metallic materials — Charpy pendulum impact test — Part 1: Test method
ISO 3183:2012, Petroleum and natural gas industries — Steel pipe for pipeline transportation systems
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 6892-2, Metallic materials — Tensile testing — Part 2: Method of test at elevated temperature
ISO 7438, Metallic materials — Bend test

This document is superseded by ISO 3183:2019 after publication of ISO 15590-1:2018. As ISO 3183:2019 is
published as ISO supplement to API Spec 5L, this document maintains the references to particular sections in ISO
3183:2012, which are considered still accurate.
ISO 7539-2, Corrosion of metals and alloys — Stress corrosion testing — Part 2: Preparation and use of
bent-beam specimens
ISO 8501-1:2007, Preparation of steel substrates before application of paints and related products — Visual
assessment of surface cleanliness — Part 1: Rust grades and preparation grades of uncoated steel substrates
and of steel substrates after overall removal of previous coatings
ISO 9712, Non-destructive testing — Qualification and certification of NDT personnel
ISO 10474, Steel and steel products — Inspection documents
ISO 10893-4, Non-destructive testing of steel tubes — Part 4: Liquid penetrant inspection of seamless and
welded steel tubes for the detection of surface imperfections
ISO 10893-5, Non-destructive testing of steel tubes — Part 5: Magnetic particle inspection of seamless and
welded ferromagnetic steel tubes for the detection of surface imperfections
ISO 10893-8, Non-destructive testing of steel tubes — Part 8: Automated ultrasonic testing of seamless and
welded steel tubes for the detection of laminar imperfections
ISO 10893-9, Non-destructive testing of steel tubes — Part 9: Automated ultrasonic testing for the detection
of laminar imperfections in strip/plate used for the manufacture of welded steel tubes
ISO 10893-10:2011, Non-destructive testing of steel tubes — Part 10: Automated full peripheral ultrasonic
testing of seamless and welded (except submerged arc-welded) steel tubes for the detection of longitudinal
and/or transverse imperfections
ISO 10893-11:2011, Non-destructive testing of steel tubes — Part 11: Automated ultrasonic testing of the
weld seam of welded steel tubes for the detection of longitudinal and/or transverse imperfections
ISO 13623, Petroleum and natural gas industries — Pipeline transportation systems
ASNT SNT-TC-1A, Recommended Practice No. SNT-TC-1A: Personnel Qualification and Certification in
Nondestructive Testing
ASTM A370, Standard Test Methods and Definitions for Mechanical Testing of Steel Products
ASTM A435, Standard Specification for Straight-Beam Ultrasonic Examination of Steel Plates
ASTM A578/A578M, Standard Specification for Straight-Beam Ultrasonic Examination of Rolled Steel
Plates for Special Applications
ASTM E18, Standard Test Methods for Rockwell Hardness of Metallic Materials
ASTM E92, Standard Test Method for Vickers Hardness of Metallic Materials
ASTM E112, Standard Test Methods for Determining Average Grain Size
ASTM E165, Standard Test Method for Liquid Penetrant Examination

This document is modified adopted as EN 14161 to exclude on-land supply systems used by the European gas
supply industry from the input of gas into the on-land transmission network up to the inlet connection of gas
appliances.
ASTM E213, Standard Practice for Ultrasonic Testing of Metal Pipe and Tubing
ASTM E214, Standard Practice for Ultrasonic Pulse-Echo Straight-Beam Contact Testing
ASTM E340, Standard Test Method for Macroetching Metals and Alloys
ASTM E709, Standard Guide for Magnetic Particle Testing
ASTM E797, Standard Practice for Measuring Thickness by Manual Ultrasonic Pulse-Echo Contact Method
ASTM G39, Standard Practice for Preparation and Use of Bent-Beam Stress-Corrosion Test Specimens
NACE TM0177:2016, Laboratory Testing of Metals for Resistance to Sulfide Stress Cracking in Hydrogen
Sulfide (H S) Environments
NACE TM0284:2016, Standard Test Method — Evaluation of Pipeline and Pressure Vessel Steels for
Resistance to Hydrogen-Induced Cracking
3 Terms and definitions
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:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
3.1
arc
curved portion of a bend
3.2
agreed
agreed upon by the manufacturer (3.17) and purchaser (3.21), and specified in the purchase order
3.3
bend angle
amount of directional change through the cold bend
3.4
bend qualification test
qualification test that produces a cold bend in accordance with the MPS (3.18) and demonstrates that
bends that meet the specified requirements of this document can be produced
3.5
bend radius
distance from the centre of curvature to the centreline axis of the bent pipe
3.6
chord
line segment connecting start and stop points of the bend zone measured at the centreline axis
3.7
defect
imperfection (3.11) of a size and/or population density greater than specific acceptance criteria
Note 1 to entry: The specific acceptance criteria are specified in ISO 3183.
3.8
extrados
outer curved section of the arc (3.1)
3.9
heat
batch of steel prepared in one steel-making operation
3.10
if agreed
required to be as prescribed, or more stringent than is prescribed, if agreed upon by the manufacturer
(3.17) and the purchaser (3.21) and specified in the purchase order
3.11
imperfection
discontinuity or irregularity in the product wall or on the product surface that is detectable through
inspection methods
3.12
indication
evidence obtained by non-destructive inspection (3.20)
3.13
cold bending
controlled bending process using presses at room temperature
3.14
inspection
activities, such as measuring, examining, testing, weighing or gauging one or more characteristics of a
product and comparing the results of such activities with the specified requirements in order to
determine conformity
3.15
intrados
inner curved section of the arc (3.1)
3.16
lamination
internal metal separation that creates layers, generally parallel to the pipe/bend surface
3.17
manufacturer
firm, company, or corporation responsible for making and marking the product
3.18
manufacturing procedure specification
MPS
document that specifies the properties and description of the mother pipe (3.19), the cold bending
procedure, the post-bending heat treatment equipment and cycle, if applicable, the qualification bend
testing results, the non-destructive testing procedures and the weld end bevel details used for the
manufacture of the cold bends
3.19
mother pipe
straight section of pipe from which a cold bend is made
3.20
non-destructive inspection
inspection (3.14) to reveal imperfections (3.11), using radiographic, ultrasonic or other methods that do
not involve disturbance, stressing or breaking of the materials
3.21
purchaser
party responsible for both the definition of requirements for a product order and for payment of that
order
3.22
submerged-arc welding
SAW
welding process that produces melting and coalescence of metals by heating them with an arc(s) between
a bare metal consumable electrode(s) and the workpiece, wherein the arc (3.1) and molten metal are
shielded by a blanket of granular flux
3.23
service condition
condition of use that is specified by the purchaser (3.21) in the purchase order
Note 1 to entry: In this document, the terms “sour service” and “offshore service” are service conditions.
3.24
strip end weld
weld that joins strip ends together
3.25
plate end weld
weld that joins plate ends together
3.26
tangent
straight section at the end of a cold bend
3.27
wall thinning
amount of reduction from the actual wall thickness of the pipe to the wall thickness in the extrados (3.8)
after cold bending (3.13)
4 Symbols and abbreviated terms
4.1 Symbols
A elongation of tensile test specimen after fracture, expressed as a percentage
L crest to valley depth
CVD
D and D outside diameters of two adjacent crests
2 4
D3 outside diameter of the intervening valley
D specified diameter, outside or inside
Dmax maximum measured diameter, outside or inside
Dmin minimum measured diameter, outside or inside
Dn nominal pipe diameter
L distance between adjacent crests for waving
O out-of-roundness
Rb bend centreline radius
Rp nominal mid-thickness radius of the mother pipe
R ultimate tensile strength
m
R yield strength for 0,5 % total elongation
t0,5
t minimum wall thickness at the bend intrados
i
t minimum wall thickness required in accordance with ISO 13623, or other
min
applicable design code, for the straight pipe adjacent to the bend, including any
corrosion allowance
4.2 Abbreviated terms
BQT bend qualification test
CB cold bending
CTOD crack tip opening displacement testing
CCVD crest to valley depth
HAZ heat-affected zone
HIC hydrogen-induced cracking
HFW high-frequency electric welding process for pipe during manufacturing
MPS manufacturing procedure specification
MT magnetic particle testing
NDT non-destructive testing
OD outside diameter
PSL product specification level
PT liquid-penetrant testing
RT radiographic testing
SAW submerged arc welding process for pipe during manufacture
SAWH submerged arc helical welding process for pipe during manufacture
SAWL submerged arc longitudinal welding process for pipe during manufacture
SSC sulfide stress-cracking
SWC step-wise cracking
UT ultrasonic testing
5D 5 × OD
10D 10 × OD
5 General requirements
5.1 Units of measurement
In this document, data are expressed in both SI units and USC units. For a specific order item, unless
otherwise stated, only one system of units shall be used, without combining data expressed in the other
system.
For data expressed in SI units, a comma is used as the decimal separator and a space is used as the
thousands separator. For data expressed in USC units, a dot (on the line) is used as the decimal separator
and a space is used as the thousands separator.
5.2 Rounding
Unless otherwise stated in this document, to determine conformance with the specified requirements,
observed or calculated values shall be rounded to the nearest unit in the last right-hand place of figures
used in expressing the limiting value, in accordance with ISO 80000-1:2009, Annex B, Rule A.
[3]
NOTE For the purposes of this provision, the rounding method of ASTM E29-04 is equivalent to ISO 80000-
1:2009, Annex B, Rule A.
5.3 Conformance to this document
A contract may specify that the manufacturer shall be responsible for conforming with all the applicable
requirements of this document. It shall be permissible for the purchaser to make any investigation
necessary to be assured of conformity by the manufacturer and to reject any material that does not
conform.
6 Designation of cold bends
Designation of cold bends according to this document, i.e. EN 14870-4, shall take one of the following
forms:
EN 14870-4-CB xxx-PSL 1;
EN 14870-4-CB xxx-PSL 2;
EN 14870-4-CB xxx-PSL 2S;
EN 14870-4-CB xxx-PSL 2O;
EN 14870-4-CB xxx-PSL 2SO
In this designation, the elements have the following meaning:
xxx: specified minimum yield strength, expressed in mega pascals (MPa);
PSL 1 or PSL 2: identifier for the technical delivery conditions class for cold bends in non-sour
service;
PSL 2S: identifier for PSL 2 bends for use in sour service conditions;
PSL 2O: identifier for PSL 2 bends for use in offshore service conditions;
PSL 2SO: Identifier for PSL 2 bends for use in both offshore and sour service conditions.
7 Design
For pipelines not designed in accordance with ISO 13623, the minimum required wall thickness of the
bend extrados can be less than t .
min
The requirements in this clause address the design of a bend against internal pressure. It is necessary
that the purchaser or designer also consider other loads, both static and dynamic, and pipeline test
conditions to demonstrate compliance with the strength requirements of ISO 13623.
8 Information provided by the purchaser
8.1 General information
The purchaser shall provide the following information:
a) number of this document and year of publication (i.e. EN 14870-4:2023);
b) bend designation of each bend;
c) quantity of bends;
d) supply of mother pipe by the purchaser or the manufacturer;
e) required bend dimensions, including:
— diameter (inside or outside),
— minimum intrados and extrados wall thickness after cold bending,
— bend radius,
— bend angle and
— tangent lengths.
f) end preparation, if different from square ends;
g) equipment and method used for cold bend.
8.2 Additional information
The purchaser should specify the following additional information:
a) minimum design temperature;
b) maximum design temperature (and any requirement for high-temperature tensile testing);
c) maximum wall thickness;
d) special dimensional requirements;
e) requirements for supplementary inspection and testing;
f) requirements for gauging and other measurements of dimensions, if different from this document,
i.e. 14870-4;
g) pipeline design standard or design factors, if different from ISO 13623;
h) pipeline operating conditions;
i) mechanical-property requirements at the maximum design temperature;
j) Charpy impact test temperature;
k) requirements for proof, burst or hydrostatic testing;
l) hold-points for witness and approval by purchaser;
m) surface condition;
n) coating or painting requirements;
o) marking requirements, if different from this document, i.e. 14870-4;
p) requirements for ends or bevel protection (e.g. end caps or bevel protectors);
q) packaging and shipping instructions;
r) third-party inspection organization;
s) inspection document required in accordance with EN 10204 or ISO 10474;
t) requirements for format and additional content of the inspection document;
u) additional requirements for hardness testing;
v) other special requirements.
8.3 Information on the mother pipe
The following information on the mother pipe shall be provided to the manufacturer:
a) purchasing specification;
b) pipe diameter, inside or outside;
c) pipe wall thickness, nominal or minimum;
d) pipe lengths;
e) pipe manufacturer;
f) pipe material specification and pipe material certificates, including chemical composition, heat
treatment, mechanical properties, dimensions and results of NDT;
g) welding procedure specification for SAWL and SAWH pipe;
h) weld-seam-repair welding-procedure specification for SAWL and SAWH pipe;
i) applicability of Annex B for sour service.
Information f), g) and h) is necessary for the design of the bending procedure by the manufacturer.
9 Manufacturing
9.1 Mother pipe
Mother pipe shall be manufactured in accordance with ISO 3183.
Mother pipe for the manufacture of PSL 2 bends shall be in accordance with ISO 3183 PSL 2.
Mother pipe for the manufacture of PSL 2S bends shall be made in accordance with ISO 3183:2012, Annex
H, with the additional requirements specified in Annex B of this document.
Mother pipe for the manufacture of PSL 2O bends shall be made in accordance with ISO 3183:2012, Annex
J.
Mother pipe for the manufacture of PSL 2SO bends shall be made in accordance with ISO 3183:2012,
Annex H; ISO 3183:2012, Annex J; and the additional requirements specified in Annex B of this document.
The mother pipe may be supplied by either the purchaser or the manufacturer.
If the mother pipe is supplied by the purchaser, the manufacturer should be consulted on the required
properties and dimensions of the mother pipe (including seam weld and seam repair weld) regarding its
suitability for cold bending.
The body of the mother pipe shall have no weld repairs.
The wall thickness of the mother pipe shall have adequate allowance for wall thinning at the extrados
due to cold bending.
9.2 Qualification test bend
The manufacture of all PSL-level test bends shall be carried out in accordance with an MPS that shall
conform to Clause 9 before commencement of production, or at the beginning of production, if agreed.
NOTE Annex A gives details on MPS.
A test bend with at least sufficient arc length to conform to Table 1 shall be manufactured in accordance
with each preliminary MPS. The inspection and testing of the test bend shall include sufficient tangents,
if included in the produced bends.
The test bend shall be tested and inspected in accordance with Clause 10. The MPS used for production
shall, for each of the essential variables in Table 1, specify
— the values recorded during the manufacturing of the test bend, and
— the permissible range during production bending.
The variation in essential variables shall not exceed the permissible limits given in Table 1.

Table 1 — Essential variables and maximum permissible variations
a
Essential variable Maximum permissible variations
Pipe grade None
Pipe manufacturer None
Mother pipe seam weld WPS and welding consumables None
Cold bending machine tools None
Mother pipe process of manufacture None
Cold bending machine None
Nominal mother pipe diameter None
Nominal mother pipe wall thickness ±3 mm (0.118 in) or ±10 % whichever is the smallest
Bend radius An approved MPS qualifies all larger radii (but not
smaller) in the following ranges:
a) 5D up to and including 7D
b) >7D up
b
Longitudinal weld seam location ±15° from the location in the test bend
Post-bending heat treatment Method: no change
+15
Soaking time:
min
Soaking temperature: ±15 °C (±27 °F)
Heating and cooling rates: by agreement
a
The permissible variations apply to the values obtained in the approved to BQT at steady state.
b
The pipe long seam shall be placed on the neutral axis during bending. It does not apply to SAWH pipes.
9.3 Production cold bending
Cold bending shall be carried out in accordance with an MPS as specified in Annex A.
9.4 Post-bending heat treatment
Post-bending heat treatment may be performed to achieve the required material properties, improve
corrosion resistance or to relieve residual stresses due to cold bending process.
The temperature of each furnace load of bends shall be monitored by thermocouples connected directly
to selected bends and shall be recorded. The type and location of the thermocouples shall be as specified
in the MPS or in the dedicated drawings issued for heat treatment loading.
Heat treatment of stress relieving after cold bending is required for up to a 10D radius, irrespectively of
the service.
Heat treatment of stress relieving after cold bending is required for any radius for sour or offshore
service.
The heat treatment of stress relieving will be carried out between 480 °C and 675 °C, with holding time
30 minutes for 25,4 mm (1 in); but never less than 30 minutes and cooling in the furnace or in still air.
The maximum cooling rate shall be 200 °C/h.
Due to the inherent characteristics of the TMCP method, plates manufactured to this specification cannot
be formed or post-weld heat treated at a temperature above 595 °C, without some risk of sustaining
irreversible and significant losses in strength and toughness.
9.5 Forming and sizing after bending
Sizing without subsequent heat treatment is permitted for ovality and diameter corrections in the
tangents provided the induced permanent strain does not exceed 0,015.

The sizing ratio, Sr, shall be derived using Formula (1):

Sr = |Da-Db| / Db
where
Da is the manufacturer-designated outside diameter after sizing, expressed in millimetres;
Db is the manufacturer-designated outside diameter before sizing, expressed in millimetres;
|Da-Db| is the absolute value of the outside diameter difference, expressed in millimetres.

9.6 Strip/plate end welds
Cold bends shall not contain coil-strip end welds or plate end welds.
9.7 Jointers and girth welds
Whenever possible, the girth weld should be at least 1 m far from the bend section. When girth welds are
within 1 m from the bend area or in the bend section, it shall be subjected to radiography examination
after bending.
9.8 End preparation
Cold bends shall be supplied with square ends unless otherwise specified by the purchaser.
10 Testing and inspection
10.1 General requirements
An MPS shall be approved or production bends accepted only after all testing and inspection required in
Clause 10 have been performed and all results meet the specified requirements.
Except where otherwise stated in Clause 10, the testing and inspectio
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