ISO 15590-1:2009

INTERNATIONAL ISO
STANDARD 15590-1
Second edition
2009-11-15
Petroleum and natural gas industries —
Induction bends, fittings and flanges for
pipeline transportation systems —
Part 1:
Induction bends
Industries du pétrole et du gaz naturel — Coudes d'induction, raccords
et brides pour systèmes de transport par conduites —
Partie 1: Coudes d'induction
Reference number
©
ISO 2009
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©  ISO 2009
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ii © ISO 2009 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Conformance. 1
2.1 Units of measurement . 1
2.2 Rounding . 1
2.3 Compliance to standard. 2
3 Normative references . 2
4 Terms and definitions. 4
5 Symbols and abbreviated terms . 6
5.1 Symbols . 6
5.2 Abbreviated terms . 6
6 Designation . 7
7 Pressure rating and design . 7
8 Information that shall be supplied by the purchaser. 8
8.1 General information. 8
8.2 Additional information. 8
8.3 Information on the mother pipe. 9
9 Manufacturing . 9
9.1 Mother pipe. 9
9.2 Qualification test bend . 10
9.3 Production bending. 10
9.4 Post-bending heat treatment . 10
9.5 Forming and sizing after bending. 10
9.6 Strip/plate end welds. 11
9.7 Jointers and girth welds . 11
9.8 End preparation . 11
10 Testing and inspection. 11
10.1 General requirements. 11
10.2 Extent of testing and inspection . 12
10.3 Chemical composition. 12
10.4 Physical testing. 12
10.5 Non-destructive testing. 19
10.6 Dimensions. 20
10.7 Gauging . 23
10.8 Hydrostatic testing . 23
11 Inspection document. 23
12 Marking . 23
Annex A (normative) Manufacturing procedure specification . 25
Annex B (normative) PSL 2S bends ordered for sour service . 27
Bibliography . 32

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 15590-1 was prepared by Technical Committee ISO/TC 67, Materials, equipment and offshore structures
for petroleum, petrochemical and natural gas industries, Subcommittee SC 2, Pipeline transportation systems.
This second edition cancels and replaces the first edition (ISO 15590-1:2001), which has been technically
revised.
It is the intent of ISO/TC 67 that the first and second edition of ISO 15590-1 both be applicable, at the option
of the purchaser (as defined in 4.20), for a period of six months from the first day of the calendar quarter
immediately following the date of publication of this second edition, after which period ISO 15590-1:2001 will
no longer be applicable.
ISO 15590 consists of the following parts, under the general title Petroleum and natural gas industries —
Induction bends, fittings and flanges for pipeline transportation systems:
⎯ Part 1: Induction bends
⎯ Part 2: Fittings
⎯ Part 3: Flanges
iv © ISO 2009 – All rights reserved

Introduction
This International Standard makes reference to line pipe and bends with delivery conditions based on
ISO 3183. Following significant revision of ISO 3183 (ISO 3183:2007), ISO 15590-1 has been reviewed and
redrafted taking cognizance of the changes to ISO 3183. In addition to general revision, and in common with
ISO 3183:2007, the Technical Committee have introduced additional requirements for special applications as
follows:
⎯ Manufacturing procedure specification (Annex A);
⎯ PSL 2 bends for sour service (Annex B).
The requirements of the annexe(s) apply only when it is (they are) specified on the purchase order.
This International Standard does not provide guidance on when it is necessary to specify the above
supplementary requirements. Instead it is the responsibility of the purchaser to specify, based upon the
intended use and design requirements, which, if any, of the supplementary requirements apply for a particular
purchase order.
It is necessary that users of this part of ISO 15590 be aware that further or differing requirements can be
needed for individual applications. This part of ISO 15590 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 any variations from this part of
ISO 15590 and provide details.

INTERNATIONAL STANDARD ISO 15590-1:2009(E)

Petroleum and natural gas industries — Induction bends,
fittings and flanges for pipeline transportation systems —
Part 1:
Induction bends
1 Scope
This part of ISO 15590 specifies the technical delivery conditions for bends made by the induction bending
process for use in pipeline transportation systems for the petroleum and natural gas industries as defined in
ISO 13623.
This part of ISO 15590 is applicable to induction bends made from seamless and welded pipe of unalloyed or
low-alloy steels.
NOTE 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 part of ISO 15590 specifies the requirements for the manufacture of two product specification levels
(PSLs) of induction bend corresponding to product specification levels given for pipe in ISO 3183.
This part of ISO 15590 is not applicable to the selection of the induction bend product specification level. It is
the responsibility of the purchaser to specify the PSL, based upon the intended use and design requirements;
see also ISO 3183:2007, Introduction.
This part of ISO 15590 is not applicable to pipeline bends made by other manufacturing processes.
2 Conformance
2.1 Units of measurement
In this International Standard, 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.
2.2 Rounding
Unless otherwise stated in this International Standard, 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 31-0:1992, Annex B, Rule A.
[2]
NOTE For the purposes of this provision, the rounding method of ASTM E29-04 is equivalent to ISO 31-0:1992,
Annex B, Rule A.
2.3 Compliance to standard
A quality management system should be applied to assist compliance with the requirements of this
International Standard.
[1]
NOTE ISO/TS 29001 gives sector-specific guidance on quality management systems.
A contract may specify that the manufacturer shall be responsible for complying with all of the applicable
requirements of this International Standard. It shall be permissible for the purchaser to make any investigation
necessary in order to be assured of compliance by the manufacturer and to reject any material that does not
comply.
3 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 31-0:1992, Quantities and units — Part 0: General principles
ISO 148-1, Metallic materials — Charpy pendulum impact test — Part 1: Test method
ISO 783, Metallic materials — Tensile testing at elevated temperature
ISO 3183:2007, 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, Metallic materials — Tensile testing at ambient temperature
ISO 7438, Metallic materials — Bend test
ISO 7539-2, Corrosion of metals and alloys — Stress corrosion testing — Part 2: Preparation and use of bent-
beam specimens
ISO 8501-1, Preparation of steel substrates before application of paints and related products — Visual
assessment of surface cleanliness — Part 1: Rust grades and preparation grades of uncoated steel
substrates and of steel substrates after overall removal of previous coatings
ISO 9303:1989, Seamless and welded (except submerged arc-welded) steel tubes for pressure purposes —
Full peripheral ultrasonic testing for the detection of longitudinal imperfections
ISO 9305, Seamless steel tubes for pressure purposes — Full peripheral ultrasonic testing for the detection of
transverse imperfections
ISO 9712, Non-destructive testing — Qualification and certification of personnel
ISO 9764:1989, Electric resistance and induction welded steel tubes for pressure purposes — Ultrasonic
testing of the weld seam for the detection of longitudinal imperfections
ISO 10124, Seamless and welded (except submerged arc-welded) steel tubes for pressure purposes —
Ultrasonic testing for the detection of laminar imperfections
ISO 10474, Steel and steel products — Inspection documents
2 © ISO 2009 – All rights reserved

ISO 11496, Seamless and welded steel tubes for pressure purposes — Ultrasonic testing of tube ends for the
detection of laminar imperfections
ISO 12094, Welded steel tubes for pressure purposes — Ultrasonic testing for the detection of laminar
imperfections in strips/plates used in the manufacture of welded tubes
ISO 12095, Seamless and welded steel tubes for pressure purposes — Liquid penetrant testing
ISO 13623, Petroleum and natural gas industries — Pipeline transportation systems
ISO 13663, Welded steel tubes for pressure purposes — Ultrasonic testing of the area adjacent to the weld
seam for the detection of laminar imperfections
ISO 13664, Seamless and welded steel tubes for pressure purposes — Magnetic particle inspection of the
tube ends for the detection of laminar imperfections
ISO 13665, Seamless and welded steel tubes for pressure purposes — Magnetic particle inspection of the
tube body for the detection of surface imperfections
1)
ASNT SNT-TC-1A , Recommended Practice No. SNT-TC-1A: Personnel Qualification and Certification in
Nondestructive Testing
2)
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
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
3)
NACE TM0177-2005 , Laboratory Testing of Metals for Resistance to Sulfide Stress Cracking in Hydrogen
Sulfide (H S) Environments
NACE TM0284-2003, Standard Test Method — Evaluation of Pipeline and Pressure Vessel Steels for
Resistance to Hydrogen-Induced Cracking

1) American Society for Nondestructive Testing, 1711 Arlingate Lane, Columbus, OH 43228-0518, USA.
2) American Society for Testing and Materials, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, USA.
3) NACE International, 1440 South Creek Drive, P.O. Box 201009, Houston, TX 77084-4906, USA.
4 Terms and definitions
For the purposes of this part of ISO 15590, the following terms and definitions apply.
4.1
arc
curved portion of a bend
4.2
as agreed
requirement that shall be as agreed upon by the manufacturer and purchaser, and specified in the purchase
order
Modified from ISO 3183:2007, 4.1.
4.3
bend angle
amount of directional change through the bend
4.4
bend qualification test
qualification test that produces a bend in accordance with the MPS and demonstrates that bends that meet
the specified requirements of this part of ISO 15590 can be produced
4.5
bend radius
distance from the centre of curvature to the centreline axis of the bent pipe
4.6
defect
imperfection of a size and/or population density greater than the acceptance criteria specified in this part of
ISO 15590
4.7
extrados
outer curved section of the bend arc
4.8
heat
batch of steel prepared in one steel-making operation
4.9
if agreed
requirement that shall be as prescribed, or more stringent than is prescribed, if agreed upon by the
manufacturer and the purchaser and specified in the purchase order
Modified from ISO 3183:2007, 4.19.
4.10
imperfection
discontinuity or irregularity in the product wall or on the product surface that is detectable by inspection
methods outlined in this International Standard
4.11
indication
evidence obtained by non-destructive inspection
4 © ISO 2009 – All rights reserved

4.12
induction bending
continuous bending process that utilizes induction heating to create a narrow, circumferential, heated band
around the material being bent
4.13
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
[ISO 3183:2007, 4.22]
4.14
intrados
inner curved section of the bend arc
4.15
lamination
internal metal separation that creates layers, generally parallel to the pipe/bend surface
4.16
manufacturer
firm, company, or corporation responsible for making and marking the product in accordance with the
requirements of this International Standard
4.17
manufacturing procedure specification
MPS
document that specifies the properties and description of the mother pipe, the bending procedure, the post-
bending heat treatment equipment and cycle, the qualification bend testing results, the non-destructive testing
procedures and the weld end bevel details used for the manufacture of the bends
4.18
mother pipe
straight section of pipe from which an induction bend is made
4.19
non-destructive inspection
inspection to reveal imperfections, using radiographic, ultrasonic or other methods specified in this
International Standard that do not involve disturbance, stressing or breaking of the materials
[ISO 3183:2007, 4.30]
4.20
purchaser
party responsible for both the definition of requirements for a product order and for payment of that order
[ISO 3183:2007, 4.38]
4.21
service condition
condition of use that is specified by the purchaser in the purchase order
NOTE In this International Standard, the terms “sour service” and “offshore service” are service conditions.
[ISO 3183:2007, 4.45]
4.22
strip/plate end weld
weld that joins strip or plate ends together
4.23
tangent
straight section at the ends of an induction bend
4.24
transition zone
areas of the start and stop points of induction heating, which include material that extends from the unheated
mother pipe to the material that has been heated to the full bending temperature
4.25
wall thinning
amount of reduction from the original wall thickness of the pipe to the wall thickness in the extrados after
bending
5 Symbols and abbreviated terms
5.1 Symbols
A
elongation of tensile test specimen after fracture, expressed as a percentage
CVD, L crest to valley depth
CVD
D and D outside diameters of two adjacent crests
2 4
D outside diameter of the intervening valley
D specified diameter, outside or inside
D maximum measured diameter, outside or inside
max
D minimum measured diameter, outside or inside
min
l distance between adjacent crests for waving
O out-of-roundness
r bend centreline radius
b
r nominal mid-thickness radius of the mother pipe
p
R ultimate tensile strength
m
R yield strength for 0,5 % total elongation
t0,5
T minimum design temperature specified by the purchaser
dmin
t minimum wall thickness at the bend intrados

i
t minimum wall thickness required in accordance with ISO 13623, or other applicable design
min
code, for the straight pipe adjacent to the bend, including any corrosion allowance
5.2 Abbreviated terms
BQT bend qualification test
CTOD crack tip opening displacement testing
DWT drop-weight tear testing
HAZ heat-affected zone
HIC hydrogen-induced cracking
HFW high-frequency electric welding process for pipe during manufacturing
6 © ISO 2009 – All rights reserved

MPS manufacturing procedure specification
MT magnetic particle testing
NDT non-destructive testing
PSL product specification level
PT liquid-penetrant testing
RT radiographic testing
SAWL submerged arc longitudinal welding process for pipe during manufacture
SAWH submerged arc helical welding process for pipe during manufacture
SSC sulfide stress-cracking
SWC step-wise cracking
UT ultrasonic testing
WPS welding procedure specification
6 Designation
Designation of induction bends shall take the form “IB xxx-PSL 1” or “IB xxx-PSL 2” or “IB xxx-PSL 2S”, where
⎯ “xxx” is the specified minimum yield strength, expressed in megapascals (MPa);
⎯ the letters “PSL 1” or “PSL 2” identify the technical delivery conditions class for induction bends in
non-sour service;
⎯ the letters “PSL 2S” identify PSL 2 bends for use in sour service conditions.
7 Pressure rating and design
The hoop stress in the induction bend due to internal fluid pressure shall not exceed the hoop stress permitted
in ISO 13623, or other applicable design code, for straight pipe in the location of the bend.
Compliance with this requirement shall be demonstrated either by calculations or by satisfying both of the
following requirements.
a) The wall thickness of the bend extrados shall be at least t .
min
b) The wall thickness at the bend intrados shall be at least as given in Equation (1):
2rr−
bp
tt=× (1)
imin
2rr−
()
bp
For pipelines not designed in accordance with ISO 13623, the wall thickness of the bend extrados may 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 that shall be supplied by the purchaser
8.1 General information
The purchaser shall provide the following information:
a) number of this part of ISO 15590 and year of publication (i.e. ISO 15590-1:2009);
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 wall thickness,
⎯ bend radius,
⎯ bend angle,
⎯ tangent lengths;
f) end preparation if different from square ends.
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 part of ISO 15590;
g) pipeline design standard or design factors, if different from ISO 13623;
h) pipeline operating conditions;
i) whether it is necessary to apply post-bending heat treatment;
j) mechanical-property requirements at the maximum design temperature;
k) Charpy impact test temperature;
l) requirements for proof, burst or hydrostatic testing;
m) hold-points for witness and approval by purchaser;
8 © ISO 2009 – All rights reserved

n) surface condition;
o) coating or painting requirements;
p) marking requirements, if different from this part of ISO 15590;
q) packaging and shipping instructions;
r) third-party inspection organization;
s) standard designation of inspection document that is required in accordance with ISO 10474;
t) requirements for format and additional content of the inspection document;
u) requirements for hardness testing;
v) other special requirements.
8.3 Information on the mother pipe
8.3.1 If the mother pipe is supplied by the purchaser, 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.
8.3.2 If available, the following additional information shall also be provided:
a) pipe material specification and pipe material certificates, including chemical composition, heat treatment,
mechanical properties, dimensions and results of NDT;
b) welding procedure specification and weld metal chemical composition for SAWL and SAWH pipe;
c) weld-seam-repair welding-procedure specification for SAWL and SAWH pipe.
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 3183:2007 PSL 2.
Mother pipe for the manufacture of PSL 2S bends shall be made in accordance with ISO 3183:2007, Annex H
with the additional requirements specified in Annex B of this part of ISO 15590.
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 as to the required
chemical composition, properties and dimensions of the mother pipe, (including seam weld and seam repair
weld) with regard to its suitability for induction bending.
The mother pipe should not contain weld repairs to the pipe body.
The wall thickness of the mother pipe shall have adequate allowance for wall thinning at the extrados due to
induction bending.
The surface of the mother pipe shall be free from contamination by low-melting-temperature metals, such as
copper, zinc, brass and aluminium.
9.2 Qualification test bend
The manufacture of all PSL-level test bends shall be carried out in accordance with an MPS that shall be
qualified in accordance with Clause 9 before commencement of production, or at the beginning of production if
agreed.
NOTE Annex A gives details of MPS.
A test bend with at least sufficient arc length to allow extraction of the necessary test specimens shall be
manufactured in accordance with each preliminary MPS. The inspection and testing of the test bend shall
include tangents and both stop and start transition zones if included in the produced bends.
The test bend shall be tested and inspected in accordance with Clause 10.
The MPS being used for production shall, for each of the essential variables in Table 1, specify
⎯ the values recorded during the manufacturing of the test bend;
⎯ the permissible range during production bending.
The variation in essential variables shall not exceed the permissible limits shown in Table 1.
9.3 Production bending
Induction bending shall be carried out in accordance with a qualified MPS as specified in Annex A.
Interruption of the induction bending operation shall result in rejection of the bend.
9.4 Post-bending heat treatment
Post-bending heat treatment of bends is not mandatory for compliance with this part of ISO 15590.
Post-bending heat treatment may be performed to achieve the required material properties, improve corrosion
resistance, remove transition zones at the ends of the bend arc or to relieve residual stresses.
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.
9.5 Forming and sizing after bending
Hot forming, including spot heating, or hot sizing after bending, shall not be performed unless followed by a
subsequent full heat treatment above the upper critical temperature.
Cold forming or sizing without subsequent heat treatment is permitted provided the induced permanent strain
does not exceed 1,5 %.
10 © ISO 2009 – All rights reserved

Table 1 — Essential variables and maximum permissible variations
a
Essential variable
Maximum permissible variations
Heat of steel None
Mother pipe seam weld WPS and welding consumables None
Surface condition By agreement
Nominal mother pipe diameter None
Nominal mother pipe wall thickness
±3 mm (0.118 in)
+25
Bend radius
For r u 5D : %
b 0
+100
For 5D < r u 10D : %
b 0
+∞
For r > 10D :
%
b 0
Forming speed ±2,5 mm/min (0.098 in/min)
Forming temperature ±25 °C (±45 °F)
Coil design None
Coolant None
Coolant flow rate or pressure
±10 %
Coolant temperature ±15 °C (± 27 °F)
Power
±5 %, in steady conditions (except for seamless pipe,
which is subject to agreement)

Induction heating frequency
±20 %
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 bend qualification test (BQT).
9.6 Strip/plate end welds
Induction bends shall not contain coil-strip end welds or plate end welds.
9.7 Jointers and girth welds
Induction bends shall not contain girth welds.
9.8 End preparation
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 inspection methods and acceptance criteria for
induction bends shall be as required by ISO 3183 for pipe of the same steel grade and type.
The upper limit of yield stress for offshore service pipe (PSL 2) may be increased by agreement.
Testing and inspection shall be carried out on bends after final heat treatment.
Test results already available for the mother pipe may be used in place of testing and inspections where
indicated in Table 2.
If the pipeline installation techniques require post-weld heat treatment of the bend, the purchaser may require
additional testing to demonstrate that the mechanical properties of the bend are also achieved after post-weld
heat treatment. The purchaser shall specify the details of the post-weld heat treatment cycle that shall be used
during the pipeline installation. The test requirements and acceptance criteria shall be by agreement.
10.2 Extent of testing and inspection
10.2.1 Qualification test bend
The extent of testing and inspection that shall be performed on each test bend is as specified in Table 2 for
each bend product specification level.
The location and type of tests shall be as specified in Table 3, with the locations for the extraction of samples
as shown in Figure 1.
For SAWH pipe, the inspection and testing requirements shall be by agreement.
10.2.2 Production bends
The extent of testing and inspection that shall be performed during production is as specified in Table 2 for
each bend product specification level.
10.2.3 Production test bends
For large bend quantities, the production-test bend frequency and the extent of destructive testing shall be by
agreement.
10.3 Chemical composition
The chemical composition of each bend shall comply with the requirements for pipe of the same grade and
type as specified in ISO 3183.
NOTE In some instances, the aluminium and/or copper contents within the limits allowed by ISO 3183 can give rise
to embrittlement and cracking during bending.
10.4 Physical testing
10.4.1 Test pieces — General
Test pieces shall be prepared in accordance with ISO 3183.
If thermal cutting has been used to remove samples, the full extent of the heat-affected region shall be
removed during the preparation of the test pieces.
10.4.2 Tensile testing
10.4.2.1 Test pieces
Round-bar test pieces machined from unflattened samples may be used by agreement.
Welds shall be ground flush. Local imperfections and mill scale may be removed.
12 © ISO 2009 – All rights reserved

Table 2 — Summary of testing and inspection requirements
a a
Test PSL 1 PSL 2 Acceptance
Chemical analysis Chemical composition M M In accordance with ISO 3183
Physical tests Tensile T T In accordance with ISO 3183
Impact N T In accordance with ISO 3183
Through-thickness hardness O T In accordance with 10.4.4.2
Surface hardness T and P T and P In accordance with 10.4.5.2
Metallography T T In accordance with 10.4.6.2
b
HIC N T In accordance with B.4.3
b
SSC N T In accordance with B.4.4
DWT N O By agreement
CTOD N O By agreement
Guided bend (weld seam) M M In accordance with ISO 3183
Flattening M M In accordance with ISO 3183
NDT Visual inspection T and P T and P In accordance with
ISO 3183 and 10.5.1
Weld seam (UT or RT) M T and P In accordance with ISO 3183
Bend ends (laminations) P P In accordance with 10.5.3
Bend body (MT or PT) T and P T and P In accordance with 10.5.4
Bend body (UT) transverse N T and P In accordance with 10.5.5
defects
Bend body (UT) laminations N M In accordance with 10.5.5
Residual magnetism ends P P In accordance with 10.5.6
Repairs P P In accordance with
ISO 3183 and 10.5.7
Dimensions Wall thickness T and P T and P In accordance with 10.6
D bend body P P In accordance with 10.6
D at ends P P In accordance with 10.6
Out-of-roundness ends P P In accordance with 10.6
Out-of-roundness body P P In accordance with 10.6
Linear dimensions P P In accordance with 10.6
Angle P P In accordance with 10.6
Radius O O In accordance with 10.6
End squareness P P In accordance with 10.6
Out of plane P P In accordance with 10.6
End preparation By agreement By agreement
Gauging By agreement By agreement
Hydrostatic test By agreement By agreement
a
M – Testing of the induction bend shall not be required if acceptable test results are available for the mother pipe. If acceptable test
results for the mother pipe are not available then the test shall be performed on either the mother pipe or the bend.
N – Not required.
O – Performance of the test or inspection on a production induction bend may be required by agreement.
P – Required for each production bend.
T – Required for each test bend.
b
Required only for PSL 2S bends.
Table 3 — Location of test pieces and type of test for destructive testing of test bends
Location Test
a
Tangent base metal Tensile
Impact
Through-thickness hardness
a
Tensile transverse
Tangent weld
Impact
Flattening
Through-thickness hardness
Metallography
Guided bend
c
Transition zones base metal extrados, start and stop
Tensile
c
Impact
c
Through-thickness hardness
c
Metallography
c
Transition zones welds, start and stop
Tensile transverse
c
Impact
Bend extrados base metal Tensile
Impact
Through-thickness hardness
de
HIC and SSC
Bend intrados base metal Tensile
Impact
Through-thickness hardness
b
Tensile transverse
Bend weld
Impact
Through-thickness hardness
Metallography
Guided bend
d
HIC and SSC
a
Testing after bending is not necessary if test results are available for mother pipe and the tangent is not heat-treated during
induction bending or subsequent heat treatment.
b
For SAWH bends, additional testing shall be by agreement.
c Where the entire length of the mother pipe, including tangents, is subject to the same continuous induction heating, cooling and
speed parameters as the bent portion during the induction bending process then, unless specified otherwise by the purchaser, these
induction bends are not considered to have transitions for testing purposes.
d Required only for PSL 2S bends.
e By agreement; requirement for HIC testing of seamless pipe bends may be waived.
14 © ISO 2009 – All rights reserved

10.4.2.2 Test method
Tensile testing at ambient temperature shall be carried out in accordance with ISO 6892 or ASTM A370.
Additional elevated-temperature tensile testing should be performed if the maximum design temperature
exceeds 50 °C. Tensile testing at elevated temperatures shall be carried out in accordance with ISO 783 and
the test location and the acceptance criteria shall be by agreement.
R , R and A shall be determined using test pieces from the base metal in the bend arc, tangent and
m t0,5
transition zones.
The percentage elongation after fracture shall be reported with reference to ISO 3183:2007, 10.2.4.2.
For weld transverse tensile tests, only R shall be required.
m
Key
1 tangent weld
2 transition zone base metal (both stop and start transitions)
3 bend extrados base metal
4 bend weld
5 transition zone weld (both stop and start transitions)
6 bend intrados base metal
7 tangent base metal
Figure 1 — Location for extraction of samples for testing
Dimensions in millimetres
Key
1 weld centreline
2 fusion line
3 fusion line plus 2 mm (0.079 in)
4 fusion line plus 5 mm (0.197 in)
Figure 2 — Location of Charpy V-notch test pieces in the weld region of SAW pipe
10.4.3 Charpy V-notch impact testing
10.4.3.1 Test pieces
Charpy V-notch test pieces shall be prepared in accordance with ISO 148-1 or ASTM A370, with the axis of
the notch perpendicular to the bend surface. The orientation and size of the test pieces shall be transverse
with the greatest possible width between 10 mm (0.394 in) and 5 mm (0.197 in). If transverse test pieces with
a minimum width of 5 mm (0.197 in), are not possible, longitudinal test pieces with the greatest possible width
between 10 mm (0.394 in) and 5 mm (0.197 in) shall be used.
Impact testing is not required if the bend dimensions are insufficient to produce longitudinal test pieces with a
minimum width of 5 mm (0.197 in).
All Charpy V-notch test pieces shall be taken from the sample at a depth of no more than 2 mm (0.079 in)
below the outer surface as illustrated in Figure 2.
Test pieces from welds in SAW pipe with a mother pipe nominal wall thickness not exceeding
25 mm (0.984 in) shall be taken across the weld with the notch at the four locations indicated in Figure 2. The
distance of notch location from the fusion line shall be determined with reference to the centreline of the test
piece. The orientation of the weld test piece shall be transverse to either the longitudinal or helical weld.
Test pieces from welds in HFW pipe shall be taken across the weld: one set with the notch located in the weld
centreline and one set with the notch located 2 mm (0.079 in) from the weld centreline. The weld centreline
shall be located by using metallographic etching techniques.
For bend weld and HAZ tests, each test piece shall be etched prior to notching in order to enable proper
placement of the notch.
F
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