SIST EN 12952-5:2022

Water-tube boilers and auxiliary installations - Part 5: Workmanship and construction of pressure parts of the boiler

This European Standard specifies requirements for the workmanship and construction of water-tube boilers as defined in EN 12952-1.

Wasserrohrkessel und Anlagenkomponenten - Teil 5: Verarbeitung und Bauausführung für drucktragende Kesselteile

Chaudières à tubes d'eau et installations auxiliaires - Partie 5: Fabrication et construction des parties sous pression des chaudières

Vodocevni kotli in pomožne napeljave - 5. del: Izdelava in izvedba tlačno obremenjenih delov kotla

Ta evropski standard določa zahteve za izdelavo in izvedbo vodocevnih kotlov iz standarda EN 12952-1.

General Information

• Status: Published
• Public Enquiry End Date: 02-Apr-2020
• Publication Date: 18-Jan-2022
• ICS: 27.060.30 - Boilers and heat exchangers
• Technical Committee: TLP - Pressure vessels
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 17-Jan-2022
• Due Date: 24-Mar-2022
• Completion Date: 19-Jan-2022
• Directive: 2014/68/EU - Directive 2014/68/EU of the European Parliament and of the Council of 15 May 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of pressure equipment
• Mandate: M/071 - Mandate to CEN for standardization in the field of Pressure equipment
• Ref Project: EN 12952-5:2021 - Water-tube boilers and auxiliary installations - Part 5: Workmanship and construction of pressure parts of the boiler

Relations

• Replaces: SIST EN 12952-5:2012 - Water-tube boilers and auxiliary installations - Part 5: Workmanship and construction of pressure parts of the boiler
• Effective Date: 01-Feb-2022

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 12952-5:2022
01-februar-2022
Nadomešča:
SIST EN 12952-5:2012
Vodocevni kotli in pomožne napeljave - 5. del: Izdelava in izvedba tlačno
obremenjenih delov kotla
Water-tube boilers and auxiliary installations - Part 5: Workmanship and construction of
pressure parts of the boiler
Wasserrohrkessel und Anlagenkomponenten - Teil 5: Verarbeitung und Bauausführung
für drucktragende Kesselteile
Chaudières à tubes d'eau et installations auxiliaires - Partie 5: Fabrication et construction
des parties sous pression des chaudières
Ta slovenski standard je istoveten z: EN 12952-5:2021
ICS:
27.060.30 Grelniki vode in prenosniki Boilers and heat exchangers
toplote
SIST EN 12952-5:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN 12952-5:2022

---------------------- Page: 2 ----------------------
SIST EN 12952-5:2022


EN 12952-5
EUROPEAN STANDARD

NORME EUROPÉENNE

December 2021
EUROPÄISCHE NORM
ICS 27.040 Supersedes EN 12952-5:2011
English Version

Water-tube boilers and auxiliary installations - Part 5:
Workmanship and construction of pressure parts of the
boiler
Chaudières à tubes d'eau et installations auxiliaires - Wasserrohrkessel und Anlagenkomponenten - Teil 5:
Partie 5: Fabrication et construction des parties sous Verarbeitung und Bauausführung für drucktragende
pression des chaudières Kesselteile
This European Standard was approved by CEN on 1 November 2021.

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, Turkey 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
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 12952-5:2021 E
worldwide for CEN national Members.

---------------------- Page: 3 ----------------------
SIST EN 12952-5:2022
EN 12952-5:2021 (E)
Contents
European foreword . 8
1 Scope . 10
2 Normative references . 10
3 Terms and definitions . 12
4 Symbols and abbreviations . 12
5 General. 12
6 Pressure part . 13
6.1 Drums, headers and similar pressure parts . 13
6.1.1 Principles for manufacturing . 13
6.1.2 Manufacturing process for header ends . 13
6.1.3 Material for header ends . 13
6.2 Material identification . 13
6.3 Material marking . 13
6.3.1 General. 13
6.3.2 Responsible personnel . 13
6.3.3 Method of marking . 14
6.3.4 Marking of non-pressure parts . 14
6.3.5 Marking of bolts and nuts . 14
6.4 Marking during manufacture . 14
6.4.1 Temporary marking. 14
6.4.2 Permanent marking . 14
6.4.3 Tube bends . 14
6.4.4 Location drawings . 14
7 Cutting, forming and fabrication tolerances . 15
7.1 Cutting material . 15
7.1.1 Methods for cutting . 15
7.1.2 Post-cutting measures. 15
7.2 Forming of drums, headers and ends . 15
7.2.1 General. 15
7.2.2 Drum and header shells . 15
7.2.3 Ends . 16
7.2.4 Plates welded prior to hot or cold forming . 16
7.2.5 Extruded openings in headers . 16
7.3 Forming of tube bends . 16
7.3.1 General. 16
7.3.2 Tube bending procedure test . 16
7.3.3 Requirements for dimensional testing . 16
7.3.4 Thinning at the tube bend extrados for tubes of nominal outside diameter 142 mm
and below . 17
7.3.5 Thickening at the tube bend intrados for tubes of nominal outside diameter above
80 mm and including 142 mm . 18
7.3.6 Thinning/thickening at the tube bend extrados/intrados for tubes of nominal outside
diameter greater than 142 mm . 18
7.3.7 Departure from circularity of the tube bends . 18
7.3.8 Post bend heat treatment of tube bends . 19
7.3.9 Post-bend heat treatment requirements . 20
7.3.10 Ripples on the intrados of tube bends . 21
7.3.11 The surface of tube bends . 23
2

---------------------- Page: 4 ----------------------
SIST EN 12952-5:2022
EN 12952-5:2021 (E)
7.3.12 Gang bending of tube panels. 23
7.3.13 Bending of composite materials tubing . 23
7.3.14 Manufacturing of tube reducers . 23
7.4 Drum and header fabrication tolerances . 24
7.4.1 Assembly tolerances for shells and fabricated from plate and end to shells. 24
7.4.2 Finished tolerances for shells . 25
7.4.3 Finished tolerances for ends . 26
8 Welding . 26
8.1 Design and other requirements specific to welding . 26
8.1.1 General . 26
8.1.2 Material selection with regard to welding . 27
8.1.3 Indication of the welded seams in the drawings . 27
8.1.4 Pre-requisites for welding . 27
8.1.5 Oxy-acetylene welding . 27
8.1.6 Butt welds in tube bends . 27
8.1.7 Minimum distances between adjacent seams . 27
8.1.8 Longitudinal butt welds in drum strakes. 28
8.1.9 Offset of longitudinal butt welds in the case of several strakes . 28
8.1.10 Joints of dissimilar materials . 28
8.1.11 Protection from the weather . 28
8.1.12 Availability of the welding procedure specification . 28
8.2 Welding consumables . 29
8.3 Welding procedure qualification . 29
8.3.1 General . 29
8.3.2 Application of EN ISO 15614-1:2017, Level 2 . 29
8.4 Qualification of welders and welding operators . 31
8.5 General production requirements for welding . 32
8.5.1 Surface condition before welding . 32
8.5.2 Assembly of components for welding . 32
8.5.3 Temporary attachments . 32
8.5.4 Stray arcing . 32
8.5.5 Traceability of welders . 32
8.6 Repairs to welds . 33
8.6.1 General . 33
8.6.2 Repair of longitudinal and circumferential butt welds of drums and headers requiring
test plates . 33
8.6.3 Non-destructive examination. 33
8.6.4 Records of weld repairs. 33
8.7 Pre-heating . 33
8.8 Post-weld heat treatment . 33
8.9 Welding subsequent to final post-weld heat treatment . 34
8.10 Welded joints, connections and production test plates. 35
8.10.1 Longitudinal and circumferential butt welds and test plates in drums and headers 35
8.10.2 Welded header end closures . 37
8.10.3 Welded branches, nozzles, stubs and other attachments on drums and headers . 37
8.10.4 Pads, reinforcing plates and manhole frames . 38
8.11 Attachment of non-pressure parts to drums and headers by welding. 38
8.12 Welding of tubes . 39
8.12.1 General . 39
8.12.2 Continuity of welding . 39
8.12.3 Completion of welding . 39
8.12.4 Proximity of butt welds in straight tubes . 39
3

---------------------- Page: 5 ----------------------
SIST EN 12952-5:2022
EN 12952-5:2021 (E)
8.12.5 Alignment of tube bores . 39
8.12.6 Angular alignment of butt welded tubes . 40
8.12.7 Fabricated bends . 40
8.12.8 Backing rings . 40
8.12.9 Purging of welds . 40
8.12.10 Welding of branches, nozzles and stubs to tubes . 40
8.12.11 Attachment by welding of non-pressure parts to tubes . 41
8.13 Flash butt welding of tubes . 41
8.14 Welded tube water walls . 41
8.15 Arc stud welding . 41
9 Mechanical connections . 41
9.1 General. 41
9.2 Access openings . 41
9.2.1 Types . 41
9.2.2 Size . 42
9.2.3 Internal doors . 42
9.2.4 External doors . 42
9.3 Branches and nozzles mechanically connected to the main pressure parts . 43
9.3.1 Scope and restrictions . 43
9.3.2 Screwed connections . 43
9.3.3 Studded connections. 43
9.4 Tube connections . 43
9.4.1 Expanded connections . 43
9.4.2 Tube to tube mechanical connections . 46
9.4.3 Connection of non-pressure parts to pressure parts . 46
10 Thermal treatment . 46
10.1 General. 46
10.2 Heating cycles and heat treatment(s) associated with plate forming operations . 46
10.2.1 Heating cycles associated with hot forming . 46
10.2.2 Heat treatment associated with forming. 47
10.2.3 Shells and strakes . 47
10.2.4 Ends . 47
10.2.5 Production test requirements for formed components . 48
10.3 Pre-heating for welding and thermal cutting . 48
10.3.1 General. 48
10.3.2 Pre-heating for welding . 48
10.3.3 Pre-heating for thermal cutting . 49
10.3.4 Measurement of pre-heat . 49
10.4 Post weld heat treatment . 50
10.4.1 General. 50
10.4.2 Methods of post weld heat treatment . 55
10.4.3 Post-weld heat treatment procedures . 58
10.5 Heat treatment of production test plates . 59
Annex A (normative) Tube bending procedure tests . 60
A.1 General. 60
A.2 Hot or cold formed bends in tubes with outside diameter ≤ 142 mm . 60
A.2.1 Types of bending processes . 60
A.2.2 Post bending heat treatment (PBHT) . 61
A.2.3 Validity range of tests . 61
4

---------------------- Page: 6 ----------------------
SIST EN 12952-5:2022
EN 12952-5:2021 (E)
A.2.4 Qualification test requirements . 62
A.2.4.1 General . 62
A.2.4.2 Ripples on intrados of the bend . 62
A.2.4.3 Surface defects . 62
A.2.4.4 Bend geometry. 63
A.2.4.5 Hardness test . 63
A.2.4.6 Mechanical tests . 63
A.2.4.7 Gang bending of tube panels. 63
A.3 Cold formed bends in tubes with outside diameter > 142 mm . 63
A.3.1 Types of bending processes . 63
A.3.2 Post bending heat treatment . 63
A.3.3 The validity range of the test . 64
A.3.4 Qualification test requirements . 64
A.3.4.1 General . 64
A.3.4.2 Ripples on intrados of the bend . 64
A.3.4.3 Surface imperfections . 64
A.3.4.4 Bend geometry. 64
A.3.4.5 Hardness test . 64
A.3.4.6 Mechanical testing . 65
A.4 Hot formed bends in tubes with outside diameter > 142 mm . 65
A.4.1 Types of bending processes . 65
A.4.2 Post bending heat treatment . 65
A.4.3 The validity range of the test . 65
A.4.4 Qualification test requirements . 65
A.4.4.1 General . 65
A.4.4.2 Ripples on intrados of the bend . 66
A.4.4.3 Surface imperfections . 66
A.4.4.4 Bend geometry. 66
A.4.4.5 Mechanical testing . 66
A.4.4.5.1 General . 66
A.4.4.5.2 Metallographic examination . 66
A.4.4.5.3 Definitive and comparative tests . 66
A.4.4.5.4 Tensile test in accordance with EN ISO 6892-1:2019 . 67
Annex B (informative) Welded pressure connections and non-pressure containing
attachments . 69
Annex C (normative) Manufacture of welded tubewalls . 70
C.1 General .
...

SLOVENSKI STANDARD
oSIST prEN 12952-5:2020
01-marec-2020
Vodocevni kotli in pomožne napeljave - 5. del: Izdelava in izvedba tlačno
obremenjenih delov kotla
Water-tube boilers and auxiliary installations - Part 5: Workmanship and construction of
pressure parts of the boiler
Wasserrohrkessel und Anlagenkomponenten - Teil 5: Verarbeitung und Bauausführung
für drucktragende Kesselteile
Chaudières à tubes d'eau et installations auxiliaires - Partie 5: Fabrication et construction
des parties sous pression des chaudières
Ta slovenski standard je istoveten z: prEN 12952-5
ICS:
27.060.30 Grelniki vode in prenosniki Boilers and heat exchangers
toplote
oSIST prEN 12952-5:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN 12952-5:2020

---------------------- Page: 2 ----------------------
oSIST prEN 12952-5:2020


DRAFT
EUROPEAN STANDARD
prEN 12952-5
NORME EUROPÉENNE

EUROPÄISCHE NORM

February 2020
ICS 27.040 Will supersede EN 12952-5:2011
English Version

Water-tube boilers and auxiliary installations - Part 5:
Workmanship and construction of pressure parts of the
boiler
Chaudières à tubes d'eau et installations auxiliaires - Wasserrohrkessel und Anlagenkomponenten - Teil 5:
Partie 5: Fabrication et construction des parties sous Verarbeitung und Bauausführung für drucktragende
pression des chaudières Kesselteile
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 269.

If this draft becomes a European Standard, 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.

This draft European Standard was established by CEN 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, Turkey and
United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.


EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 12952-5:2020 E
worldwide for CEN national Members.

---------------------- Page: 3 ----------------------
oSIST prEN 12952-5:2020
prEN 12952-5:2020 (E)
Contents Page

European foreword . 8
1 Scope . 10
2 Normative references . 10
3 Terms and definitions . 12
4 Symbols and abbreviations . 12
5 General. 12
6 Pressure part . 12
6.1 Drums, headers and similar pressure parts . 12
6.1.1 Principles for manufacturing . 12
6.1.2 Manufacturing process for header ends . 13
6.1.3 Material for header ends . 13
6.2 Material identification . 13
6.3 Material marking . 13
6.3.1 General. 13
6.3.2 Responsible personnel . 13
6.3.3 Method of marking . 14
6.3.4 Marking of non-pressure parts . 14
6.3.5 Marking of bolts and nuts . 14
6.4 Marking during manufacture . 14
6.4.1 Temporary marking. 14
6.4.2 Permanent marking . 14
6.4.3 Tube bends . 14
6.4.4 Location drawings . 14
7 Cutting, forming and fabrication tolerances . 15
7.1 Cutting material . 15
7.1.1 Methods for cutting . 15
7.1.2 Post-cutting measures. 15
7.2 Forming of drums, headers and ends . 15
7.2.1 General. 15
7.2.2 Drum and header shells . 15
7.2.3 Ends . 16
7.2.4 Plates welded prior to hot or cold forming . 16
7.2.5 Extruded openings in headers . 16
7.3 Forming of tube bends . 16
7.3.1 General. 16
7.3.2 Tube bending procedure test . 16
7.3.3 Requirements for dimensional testing . 16
7.3.4 Thinning at the tube bend extrados for tubes of nominal outside diameter 142 mm
and below . 17
7.3.5 Thickening at the tube bend intrados for tubes of nominal outside diameter above
80 mm and including 142 mm . 18
7.3.6 Thinning/thickening at the tube bend extrados/intrados for tubes of nominal
outside diameter greater than 142 mm. 18
7.3.7 Departure from circularity of the tube bends . 18
7.3.8 Post bend heat treatment of tube bends . 19
7.3.9 Post-bend heat treatment requirements . 20
2

---------------------- Page: 4 ----------------------
oSIST prEN 12952-5:2020
prEN 12952-5:2020 (E)
7.3.10 Ripples on the intrados of tube bends . 21
7.3.11 The surface of tube bends . 22
7.3.12 Gang bending of tube panels. 23
7.3.13 Bending of composite materials tubing . 23
7.3.14 Manufacturing of tube reducers . 23
7.4 Drum and header fabrication tolerances . 24
7.4.1 Assembly tolerances for shells and fabricated from plate and end to shells. 24
7.4.2 Finished tolerances for shells . 25
7.4.3 Finished tolerances for ends . 26
8 Welding . 26
8.1 Design and other requirements specific to welding . 26
8.1.1 General . 26
8.1.2 Material selection with regard to welding . 27
8.1.3 Indication of the welded seams in the drawings . 27
8.1.4 Pre-requisites for welding . 27
8.1.5 Oxy-acetylene welding . 27
8.1.6 Butt welds in tube bends . 27
8.1.7 Minimum distances between adjacent seams . 27
8.1.8 Longitudinal butt welds in drum strakes. 28
8.1.9 Offset of longitudinal butt welds in the case of several strakes . 28
8.1.10 Joints of dissimilar materials . 28
8.1.11 Protection from the weather . 28
8.1.12 Availability of the welding procedure specification . 28
8.2 Welding consumables . 29
8.3 Welding approvals . 29
8.3.1 Approval of fusion welding procedures . 29
8.3.2 Approval and training of welders . 29
8.4 General production requirements for welding . 30
8.4.1 Surface condition before welding . 30
8.4.2 Assembly of components for welding . 30
8.4.3 Temporary attachments . 30
8.4.4 Stray arcing . 30
8.4.5 Traceability of welders . 31
8.5 Repairs to welds . 31
8.5.1 General . 31
8.5.2 Repair of longitudinal and circumferential butt welds of drums and headers
requiring test plates . 31
8.5.3 Non-destructive examination. 31
8.5.4 Records of weld repairs. 31
8.6 Pre-heating . 31
8.7 Post-weld heat treatment . 31
8.8 Welding subsequent to final post-weld heat treatment . 32
8.9 Welded joints, connections and production test plates. 33
8.9.1 Longitudinal and circumferential butt welds and test plates in drums and headers . 33
8.9.2 Welded header end closures . 35
8.9.3 Welded branches, nozzles, stubs and other attachments on drums and headers . 35
8.9.4 Pads, reinforcing plates and manhole frames . 36
8.10 Attachment of non-pressure parts to drums and headers by welding. 36
8.11 Welding of tubes . 37
8.11.1 General . 37
8.11.2 Continuity of welding . 37
8.11.3 Completion of welding . 37
3

---------------------- Page: 5 ----------------------
oSIST prEN 12952-5:2020
prEN 12952-5:2020 (E)
8.11.4 Proximity of butt welds in straight tubes . 37
8.11.5 Alignment of tube bores . 37
8.11.6 Angular alignment of butt welded tubes . 38
8.11.7 Fabricated bends . 38
8.11.8 Backing rings . 38
8.11.9 Purging of welds . 38
8.11.10 Welding of branches, nozzles and stubs to tubes . 38
8.11.11 Attachment by welding of non-pressure parts to tubes . 39
8.12 Flash butt welding of tubes . 39
8.13 Welded tube water walls . 39
8.14 Arc stud welding . 39
9 Mechanical connections . 39
9.1 General. 39
9.2 Access openings . 39
9.2.1 Types . 39
9.2.2 Size . 40
9.2.3 Internal doors . 40
9.2.4 External doors . 41
9.3 Branches and nozzles mechanically connected to the main pressure parts . 41
9.3.1 Scope and restrictions . 41
9.3.2 Screwed connections . 41
9.3.3 Studded connections. 41
9.4 Tube connections . 41
9.4.1 Expanded connections . 41
9.4.2 Tube to tube mechanical connections . 44
9.4.3 Connection of non-pressure parts to pressure parts . 44
10 Thermal treatment . 44
10.1 General. 44
10.2 Heating cycles and heat treatment(s) associated with plate forming operations . 44
10.2.1 Heating cycles associated with hot forming . 44
10.2.2 Heat treatment associated with forming. 45
10.2.3 Shells and strakes . 45
10.2.4 Ends . 45
10.2.5 Production test requirements for formed components . 46
10.3 Pre-heating for welding and thermal cutting . 46
10.3.1 General. 46
10.3.2 Pre-heating for welding . 46
10.3.3 Pre-heating for thermal cutting . 47
10.3.4 Measurement of pre-heat . 47
10.4 Post weld heat treatment . 48
10.4.1 General. 48
10.4.2 Methods of post weld heat treatment . 53
10.4.3 Post-weld heat treatment procedures . 56
10.5 Heat treatment of production test plates . 56
Annex A (informative) Tube bending procedure tests . 57
A.1 General. 57
A.2 Hot or cold formed bends in tubes with outside diameter ≤ 142 mm . 57
A.2.1 Types of bending processes . 57
A.2.2 Post bending heat treatment (PBHT) . 58
4

---------------------- Page: 6 ----------------------
oSIST prEN 12952-5:2020
prEN 12952-5:2020 (E)
A.2.3 Validity range of tests. 58
A.2.4 Qualification test requirements . 59
A.2.4.1 General . 59
A.2.4.2 Ripples on intrados of the bend . 59
A.2.4.3 Surface defects . 59
A.2.4.4 Bend geometry. 60
A.2.4.5 Hardness test . 60
A.2.4.6 Mechanical tests . 60
A.2.4.7 Gang bending of tube panels. 60
A.3 Cold formed bends in tubes with outside diameter > 142 mm . 60
A.3.1 Types of bending processes . 60
A.3.2 Post bending heat treatment . 60
A.3.3 The validity range of the test . 61
A.3.4 Qualification test requirements . 61
A.3.4.1 General . 61
A.3.4.2 Ripples on intrados of the bend . 61
A.3.4.3 Surface imperfections . 61
A.3.4.4 Bend geometry. 61
A.3.4.5 Hardness test . 61
A.3.4.6 Mechanical testing . 61
A.4 Hot formed bends in tubes with outside diameter > 142 mm . 62
A.4.1 Types of bending processes . 62
A.4.2 Post bending heat treatment . 62
A.4.3 The validity range of the test . 62
A.4.4 Qualification test requirements .
...