SIST EN ISO 14713-2:2020
(Main)Zinc coatings - Guidelines and recommendations for the protection against corrosion of iron and steel in structures - Part 2: Hot dip galvanizing (ISO 14713-2:2019)
Zinc coatings - Guidelines and recommendations for the protection against corrosion of iron and steel in structures - Part 2: Hot dip galvanizing (ISO 14713-2:2019)
This document gives guidelines and recommendations for the general principles ofdesign appropriate to articles to be hot dip galvanized after fabrication (e.g.in accordance with ISO 1461) for the corrosion protection of, for example,articles that have been manufactured in accordance with EN 1090-2. This documentdoes not apply to hot dip galvanized coatings applied to continuous wire orsheet (e.g. to EN 10346).
Zinküberzüge - Leitfäden und Empfehlungen zum Schutz von Eisen- und Stahlkonstruktionen vor Korrosion - Teil 2: Feuerverzinken (ISO 14713-2:2019)
Dieses Dokument gibt Leitfäden und Empfehlungen für die allgemeinen Grundlagen der Gestaltung von Bauteilen, die zum Schutz gegen Korrosion einen Überzug durch Feuerverzinken nach der Fertigung (z. B. nach ISO 1461) erhalten, z. B. für Bauteile, die nach EN 1090 2 hergestellt wurden.
Dieses Dokument gilt nicht für Feuerverzinkungsüberzüge, die im kontinuierlichen Verfahren auf Stahldraht oder -band aufgebracht werden (z. B. nach EN 10346).
Revêtements de zinc - Lignes directrices et recommandations pour la protection contre la corrosion du fer et de l'acier dans les constructions - Partie 2: Galvanisation à chaud (ISO 14713-2:2019)
Le présent document donne des lignes directrices et des recommandations concernant les principes généraux de conception appropriés pour les pièces à galvaniser à chaud après fabrication (par exemple conformément à l'ISO 1461) utilisées pour la protection contre la corrosion, par exemple, de pièces qui ont été fabriquées conformément à l'EN 1090‑2.
Le présent document ne s'applique pas aux revêtements galvanisés à chaud appliqués sur fil ou sur tôle en continu (par exemple selon l'EN 10346).
Cinkove prevleke - Smernice in priporočila za zaščito železnih in jeklenih konstrukcij proti koroziji - 2. del: Vroče pocinkavanje (ISO 14713-2:2019)
Ta dokument vsebuje smernice in priporočila za splošna načela oblikovanja izdelkov, ki se jih za zaščito pred korozijo po izdelavi vroče pocinka (npr. v skladu s standardom ISO 1461), na primer izdelkov, ki so bili izdelani v skladu s standardom EN 1090-2. Ta dokument se ne uporablja za vroče pocinkane prevleke, ki se nanašajo na neprekinjeno žico ali pločevino (npr. v skladu s standardom EN 10346).
General Information
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Buy Standard
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 14713-2:2020
01-marec-2020
Nadomešča:
SIST EN ISO 14713-2:2010
Cinkove prevleke - Smernice in priporočila za zaščito železnih in jeklenih
konstrukcij proti koroziji - 2. del: Vroče pocinkavanje (ISO 14713-2:2019)
Zinc coatings - Guidelines and recommendations for the protection against corrosion of
iron and steel in structures - Part 2: Hot dip galvanizing (ISO 14713-2:2019)
Zinküberzüge - Leitfäden und Empfehlungen zum Schutz von Eisen- und
Stahlkonstruktionen vor Korrosion - Teil 2: Feuerverzinken (ISO 14713-2:2019)
Revêtements de zinc - Lignes directrices et recommandations pour la protection contre
la corrosion du fer et de l'acier dans les constructions - Partie 2: Galvanisation à chaud
(ISO 14713-2:2019)
Ta slovenski standard je istoveten z: EN ISO 14713-2:2020
ICS:
25.220.40 Kovinske prevleke Metallic coatings
91.080.10 Kovinske konstrukcije Metal structures
91.080.13 Jeklene konstrukcije Steel structures
SIST EN ISO 14713-2:2020 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 14713-2:2020
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SIST EN ISO 14713-2:2020
EN ISO 14713-2
EUROPEAN STANDARD
NORME EUROPÉENNE
January 2020
EUROPÄISCHE NORM
ICS 25.220.40 Supersedes EN ISO 14713-2:2009
English Version
Zinc coatings - Guidelines and recommendations for the
protection against corrosion of iron and steel in structures
- Part 2: Hot dip galvanizing (ISO 14713-2:2019)
Revêtements de zinc - Lignes directrices et Zinküberzüge - Leitfäden und Empfehlungen zum
recommandations pour la protection contre la Schutz von Eisen- und Stahlkonstruktionen vor
corrosion du fer et de l'acier dans les constructions - Korrosion - Teil 2: Feuerverzinken (ISO 14713-2:2019)
Partie 2: Galvanisation à chaud (ISO 14713-2:2019)
This European Standard was approved by CEN on 20 December 2019.
This European Standard was corrected and reissued by the CEN-CENELEC Management Centre on 12 February 2020.
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 NORMALISATIO N
EUROPÄISCHES KOMITEE FÜR NORMUN G
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. EN ISO 14713-2:2020 E
worldwide for CEN national Members.
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SIST EN ISO 14713-2:2020
EN ISO 14713-2:2020 (E)
Contents Page
European foreword . 3
2
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SIST EN ISO 14713-2:2020
EN ISO 14713-2:2020 (E)
European foreword
This document (EN ISO 14713-2:2020) has been prepared by Technical Committee ISO/TC 107
"Metallic and other inorganic coatings" in collaboration with Technical Committee CEN/TC 262
“Metallic and other inorganic coatings, including for corrosion protection and corrosion testing of
metals and alloys” the secretariat of which is held by BSI.
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 July 2020, and conflicting national standards shall be
withdrawn at the latest by July 2020.
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.
This document supersedes EN ISO 14713-2:2009.
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, 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 the
United Kingdom.
Endorsement notice
The text of ISO 14713-2:2019 has been approved by CEN as EN ISO 14713-2:2020 without any
modification.
3
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SIST EN ISO 14713-2:2020
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SIST EN ISO 14713-2:2020
INTERNATIONAL ISO
STANDARD 14713-2
Second edition
2019-10
Zinc coatings — Guidelines and
recommendations for the protection
against corrosion of iron and steel in
structures —
Part 2:
Hot dip galvanizing
Revêtements de zinc — Lignes directrices et recommandations
pour la protection contre la corrosion du fer et de l'acier dans les
constructions —
Partie 2: Galvanisation à chaud
Reference number
ISO 14713-2:2019(E)
©
ISO 2019
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SIST EN ISO 14713-2:2020
ISO 14713-2:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
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SIST EN ISO 14713-2:2020
ISO 14713-2:2019(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Design for hot dip galvanizing . 2
4.1 General . 2
4.2 Surface preparation . 2
4.3 Procedures related to design considerations . 2
4.4 Design features . 3
4.5 Tolerances . 3
5 Design for storage and transport . 3
6 Effect of article condition on quality of hot dip galvanizing . 4
6.1 General . 4
6.2 Material composition . 4
6.3 Castings . 5
6.4 Surface condition . 6
6.5 Influence of steel surface roughness on the hot dip galvanized coating thickness . 6
6.6 Influence of thermal cutting processes and welding . 6
6.6.1 Thermal cutting . 6
6.6.2 Welding . 6
6.6.3 Free edges . 6
6.7 Effect of internal stresses in the steel article . 7
6.7.1 General. 7
6.7.2 Distortion cracking . 7
6.7.3 Hydrogen embrittlement . 7
6.7.4 Strain age embrittlement . . 7
6.7.5 Liquid metal assisted cracking or liquid metal embrittlement . 8
6.8 Large objects or thick steels . 8
6.9 Hot dip galvanizing practice . 8
7 Effect of hot dip galvanizing process on the article . 8
7.1 Dimensional tolerances on mating threads . 8
7.2 Effect of process heat . 9
8 After-treatments . 9
Annex A (informative) Preferred designs of articles for hot dip galvanizing .10
Bibliography .21
© ISO 2019 – All rights reserved iii
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SIST EN ISO 14713-2:2020
ISO 14713-2:2019(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 of 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 www .iso
.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 107, Metallic and other inorganic coatings,
Subcommittee SC 4, Hot dip coatings (galvanized, etc.).
This second edition cancels and replaces the first edition (ISO 14713-2:2009), which has been technically
revised. The main changes compared with the previous edition are as follows:
— minor technical changes have been made and two new notes have been added to Table 1;
— improvements have been made to the clarity of recommendations throughout Clause 6;
— extensive revisions have been made to the figures in Annex A;
— Tables A.1, A.2 and A.3 have been added in Annex A.
A list of all parts in the ISO 14713 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2019 – All rights reserved
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SIST EN ISO 14713-2:2020
ISO 14713-2:2019(E)
Introduction
The protection afforded by the hot dip galvanized coating to the article will depend upon the method
of application of the coating, the design of the article and the specific environment to which the article
is exposed. The hot dip galvanized article can be further protected by the application of additional
coatings (outside the scope of this document), such as organic coatings (paints or powder coatings).
When applied to hot dip galvanized articles, this combination of coatings is often known as a “duplex
system”.
Specific product-related requirements, for which specific standards could exist (e.g. for hot dip
galvanized coatings on tubes or fasteners), take precedence over these general recommendations.
© ISO 2019 – All rights reserved v
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SIST EN ISO 14713-2:2020
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SIST EN ISO 14713-2:2020
INTERNATIONAL STANDARD ISO 14713-2:2019(E)
Zinc coatings — Guidelines and recommendations for
the protection against corrosion of iron and steel in
structures —
Part 2:
Hot dip galvanizing
1 Scope
This document gives guidelines and recommendations for the general principles of design appropriate
to articles to be hot dip galvanized after fabrication (e.g. in accordance with ISO 1461) for the corrosion
protection of, for example, articles that have been manufactured in accordance with EN 1090-2.
This document does not apply to hot dip galvanized coatings applied to continuous wire or sheet (e.g. to
EN 10346).
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 8044, Corrosion of metals and alloys — Basic terms and definitions
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8044 and the following 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 http: //www .electropedia .org/
3.1
hot dip galvanizing
formation of a coating of zinc and/or zinc-iron alloys on iron and steel products by dipping prepared
steel or cast irons in the zinc melt
3.2
hot dip galvanized coating
coating obtained by hot dip galvanizing (3.1)
Note 1 to entry: The term “hot dip galvanized coating” is subsequently referred to as the “coating”.
3.3
duplex system
hot dip galvanized coating (3.2) with an additional paint or powder coating
© ISO 2019 – All rights reserved 1
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SIST EN ISO 14713-2:2020
ISO 14713-2:2019(E)
4 Design for hot dip galvanizing
4.1 General
It is essential that the design of any article required to be galvanized should take into account not
only the function of the article and its method of manufacture, but also the limitations imposed by the
finish. Annex A illustrates some of the important design features, some of which are specific to hot dip
galvanizing.
Some internal stresses in the articles to be galvanized will be relieved during the hot dip galvanizing
process and this can cause deformation or damage to the coated article. These internal stresses arise
from the finishing operations at the fabrication stage, such as cold forming, welding, oxy-cutting or
drilling, and from the residual stresses inherited from the rolling mill.
The purchaser should seek the advice of the galvanizer before designing or making a product that is
subsequently to be hot dip galvanized, as it can be necessary to adapt the construction of the article for
the hot dip galvanizing process.
4.2 Surface preparation
The design and the materials used should permit good surface preparation. This is essential for the
production of a high-quality coating (see 6.4).
Graphite exposed at the surface of iron castings interferes with wetting by molten metal and those
castings that have been annealed can have silica particles in the surface layers that have to be removed
in order to obtain a good-quality coating. Grit blasting is recommended both before and after annealing.
4.3 Procedures related to design considerations
The hot dip bath and associated plant should be of adequate capacity to process the articles to be hot dip
coated with zinc. Preferably, articles should be designed to enable coating in a single dipping operation.
Articles that are too large for the available baths may be partially immersed and then reversed for
length or depth, so that a complete coating is obtained. Partial immersion (and then dipping for a second
time to complete the coating) is less common than the single, complete immersion operation.
All work is secured during immersion in the baths. Arrangements for lifting and handling should be
made before articles are delivered to the galvanizer. When necessary, the customer should consult
the galvanizer and advise of any limitations (e.g. on the use of existing holes). Lifting lugs are often
incorporated to assist general handling.
Articles may be held in racks or jigs. Some contact marks can be visible after hot dip galvanizing in such
cases. The dipping operation involves vertical movement out of the bath, but the parts being withdrawn
may be inclined at an angle.
The processing sequence requires the circulation of air, pretreatment liquids and zinc to all surfaces
of the article. Air pockets prevent local surface preparation and give uncoated surfaces. Liquids in
enclosed air vaporize at the hot dip galvanizing temperature of about 450 °C and the force generated
can cause buckling or explosions. Excess zinc can adhere poorly, can look unattractive and is wasteful.
Suitable articles, e.g. heat exchangers and gas cylinders, can, if required, be hot dip galvanized on the
outside only. This involves special techniques and equipment (e.g. to push the article into the bath
against the buoyancy of the molten zinc) and a specialist galvanizer should be consulted in advance.
Hot dip galvanizing of hollow sections ensures protection of both internal and external surfaces. Small
amounts of trapped zinc ash can be unavoidable within hollow sections and, for certain shapes and
designs, cannot be removed.
2 © ISO 2019 – All rights reserved
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SIST EN ISO 14713-2:2020
ISO 14713-2:2019(E)
4.4 Design features
Preferred design features for articles to be hot dip galvanized are shown in Annex A.
WARNING — It is essential that sealed compartments be avoided or be vented, otherwise there
is a serious risk of explosion that could cause serious injury to operators. This aspect of design
shall be given careful consideration and is essential in order to maintain satisfactory standards
of health and safety for operators.
In addition to provision for venting and draining of tubular fabrications, holes also allow a coating to
be formed on the inside surfaces and therefore ensure better protection for the article. Occasionally, at
sufficiently high levels of residual stress in the article, stress relief can occur at the hot dip galvanizing
temperature. This is one of the main causes of unexpected distortion or cracking of the steel article.
Symmetrical sections are preferred and, as far as possible, large variations in thickness or cross-section,
e.g. thin sheet welded to thick angles, should be avoided. Welding and fabrication techniques should be
chosen to minimize the introduction of unbalanced stresses. Differential thermal expansion should be
minimized during welding and processing. Heat treatment can be desirable before hot dip galvanizing.
The purchaser should discuss with the galvanizer the requirements for coating and assembly of
fabricated articles before galvanizing. Compact sub-assemblies (which occupy minimum bath space)
are the most economical to galvanize. Welding is preferable before hot dip galvanizing, to ensure a
continuous hot dip galvanized coating over the weld.
Articles should be designed so as to assist the access and drainage of molten metal and so that air locks
are avoided. A smooth profile, avoiding unnecessary edges and corners, assists hot dip galvanizing.
This, combined with bolting after galvanizing, improves long-term corrosion resistance.
Holes that are necessary in structures for the hot dip galvanizing process are preferably made before
assembly and by cutting or grinding off corners of sections; this facilitates the absence of “pockets” in
which excess molten zinc can solidify. When already assembled, burning could be the optimum method
of producing holes, as the space available for drilling may not allow the hole to be close enough to the
edge or corners.
Internal venting of hollow sections should be avoided. If internal venting is unavoidable, it should
be agreed in advance with the galvanizer [see also ISO 1461:2009, A.2, e)] and the customer should
ensure that:
a) the holes are of maximum possible size;
b) provision for internal venting is adequately documented (e.g. by photography) before assembly.
4.5 Tolerances
The thickness of the coating is determined mainly by the nature and thickness of the steel. On mating
surfaces and at holes, extra tolerance should be provided to allow for the thickness of the coating metal.
For coatings on flat surfaces, an allowance of at least 1 mm has been found satisfactory. See ISO 1461
for definitions of significant surfaces and acceptance criteria for the coating. For threaded work, for
example, for hot dip galvanized and centrifuged nuts and bolts, current practices differ according to the
country. See 7.1.
5 Design for storage and transport
Hot dip galvanized articles should be stacked securely so that the articles can be handled, stored and
transported safely.
Where there is a specific need to minimize the development of wet-storage staining (primarily basic
zinc oxide and zinc hydroxide, formed on the surface of the galvanized coating during storage of articles
in humid conditions), this should be communicated by the purchaser to the galvanizer at the time of
ordering and any relevant control measures should be agreed upon.
© ISO 2019 – All rights reserved 3
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SIST EN ISO 14713-2:2020
ISO 14713-2:2019(E)
Such measures can include, for example, storage of articles such that free movement of air across the
surfaces of the article is allowed, the use of spacers to minimize contact areas on the work, chemical
post-treatment or avoidance of close nesting of work (where the design allows this). Shrink wrapping
can lead to water retention within the articles and subsequent wet-storage staining.
In accordance with ISO 1461, the presence of wet-storage staining is not a cause for rejection, provided
the coating thickness remains above the specified minimum requirements at the time of acceptance
inspection.
6 Effect of article condition on quality of hot dip galvanizing
6.1 General
Most steels can be hot dip galvanized in accordance with ISO 1461. This includes unalloyed carbon
steels (see, e.g., EN 10025-2), fine-grained steels (see, e.g., EN 10025-3 and EN 10025-4), quenched
and tempered steels, hollow sections that are hot finished (see, e.g., EN 10210-1), hollow sections that
are cold finished (see, e.g., EN 10219-1), reinforcement steels (see, e.g., EN 10080 and EN 10348-2),
fastener grade steels [see, e.g., ISO 898 (all parts)], grey cast iron (see, e.g., EN 1561) and malleable cast
iron (see, e.g., EN 1562). Where other ferrous metals are to be galvanized, adequate information or
samples should be provided by the purchaser for the galvanizer to decide whether these steels can be
satisfactorily galvanized. Sulfur-containing free-cutting steels are normally unsuitable. Stainless steels
are unsuitable.
6.2 Material composition
Certain elements, in particular silicon (Si) and phosphorus (P), in the steel surface can affect hot
dip galvanizing by prolonging the reaction between iron and molten zinc. Therefore, certain steel
compositions can achieve more consistent coatings with regard to appearance, thickness and
smoothness. The prior history of the steel (e.g. whether hot rolled or cold rolled) can also affect its
reaction with molten zinc. Where aesthetics are important or where particular coating thickness
or surface smoothness criteria exist, specialist advice on steel selection should be sought prior to
fabrication of the article or hot dip galvanizing.
Table 1 gives simplified guidance on steel compositions that are associated with certain typical coating
characteristics when galvanizing is carried out at temperatures of 440 °C to 460 °C.
4 © ISO 2019 – All rights reserved
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SIST EN ISO 14713-2:2020
ISO 14
...
SLOVENSKI STANDARD
SIST EN ISO 14713-2:2020
01-marec-2020
Nadomešča:
SIST EN ISO 14713-2:2010
Cinkove prevleke - Smernice in priporočila za zaščito železnih in jeklenih
konstrukcij proti koroziji - 2. del: Vroče pocinkavanje (ISO 14713-2:2019)
Zinc coatings - Guidelines and recommendations for the protection against corrosion of
iron and steel in structures - Part 2: Hot dip galvanizing (ISO 14713-2:2019)
Zinküberzüge - Leitfäden und Empfehlungen zum Schutz von Eisen- und
Stahlkonstruktionen vor Korrosion - Teil 2: Feuerverzinken (ISO 14713-2:2019)
Revêtements de zinc - Lignes directrices et recommandations pour la protection contre
la corrosion du fer et de l'acier dans les constructions - Partie 2: Galvanisation à chaud
(ISO 14713-2:2019)
Ta slovenski standard je istoveten z: EN ISO 14713-2:2020
ICS:
25.220.40 Kovinske prevleke Metallic coatings
91.080.10 Kovinske konstrukcije Metal structures
91.080.13 Jeklene konstrukcije Steel structures
SIST EN ISO 14713-2:2020 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST EN ISO 14713-2:2020
---------------------- Page: 2 ----------------------
SIST EN ISO 14713-2:2020
EN ISO 14713-2
EUROPEAN STANDARD
NORME EUROPÉENNE
January 2020
EUROPÄISCHE NORM
ICS 25.220.40 Supersedes EN ISO 14713-2:2009
English Version
Zinc coatings - Guidelines and recommendations for the
protection against corrosion of iron and steel in structures
- Part 2: Hot dip galvanizing (ISO 14713-2:2019)
Revêtements de zinc - Lignes directrices et Zinküberzüge - Leitfäden und Empfehlungen zum
recommandations pour la protection contre la Schutz von Eisen- und Stahlkonstruktionen vor
corrosion du fer et de l'acier dans les constructions - Korrosion - Teil 2: Feuerverzinken (ISO 14713-2:2019)
Partie 2: Galvanisation à chaud (ISO 14713-2:2019)
This European Standard was approved by CEN on 20 December 2019.
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
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 14713-2:2020 E
worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 14713-2:2020
EN ISO 14713-2:2020 (E)
Contents Page
European foreword . 3
2
---------------------- Page: 4 ----------------------
SIST EN ISO 14713-2:2020
EN ISO 14713-2:2020 (E)
European foreword
This document (EN ISO 14713-2:2020) has been prepared by Technical Committee ISO/TC 107
"Metallic and other inorganic coatings" in collaboration with Technical Committee CEN/TC 262
“Metallic and other inorganic coatings, including for corrosion protection and corrosion testing of
metals and alloys” the secretariat of which is held by BSI.
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 July 2020, and conflicting national standards shall be
withdrawn at the latest by April 2020.
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.
This document supersedes EN ISO 14713-2:2009.
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, 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 the
United Kingdom.
Endorsement notice
The text of ISO 14713-2:2019 has been approved by CEN as EN ISO 14713-2:2020 without any
modification.
3
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SIST EN ISO 14713-2:2020
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SIST EN ISO 14713-2:2020
INTERNATIONAL ISO
STANDARD 14713-2
Second edition
2019-10
Zinc coatings — Guidelines and
recommendations for the protection
against corrosion of iron and steel in
structures —
Part 2:
Hot dip galvanizing
Revêtements de zinc — Lignes directrices et recommandations
pour la protection contre la corrosion du fer et de l'acier dans les
constructions —
Partie 2: Galvanisation à chaud
Reference number
ISO 14713-2:2019(E)
©
ISO 2019
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SIST EN ISO 14713-2:2020
ISO 14713-2:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 14713-2:2020
ISO 14713-2:2019(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Design for hot dip galvanizing . 2
4.1 General . 2
4.2 Surface preparation . 2
4.3 Procedures related to design considerations . 2
4.4 Design features . 3
4.5 Tolerances . 3
5 Design for storage and transport . 3
6 Effect of article condition on quality of hot dip galvanizing . 4
6.1 General . 4
6.2 Material composition . 4
6.3 Castings . 5
6.4 Surface condition . 6
6.5 Influence of steel surface roughness on the hot dip galvanized coating thickness . 6
6.6 Influence of thermal cutting processes and welding . 6
6.6.1 Thermal cutting . 6
6.6.2 Welding . 6
6.6.3 Free edges . 6
6.7 Effect of internal stresses in the steel article . 7
6.7.1 General. 7
6.7.2 Distortion cracking . 7
6.7.3 Hydrogen embrittlement . 7
6.7.4 Strain age embrittlement . . 7
6.7.5 Liquid metal assisted cracking or liquid metal embrittlement . 8
6.8 Large objects or thick steels . 8
6.9 Hot dip galvanizing practice . 8
7 Effect of hot dip galvanizing process on the article . 8
7.1 Dimensional tolerances on mating threads . 8
7.2 Effect of process heat . 9
8 After-treatments . 9
Annex A (informative) Preferred designs of articles for hot dip galvanizing .10
Bibliography .21
© ISO 2019 – All rights reserved iii
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SIST EN ISO 14713-2:2020
ISO 14713-2:2019(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 of 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 www .iso
.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 107, Metallic and other inorganic coatings,
Subcommittee SC 4, Hot dip coatings (galvanized, etc.).
This second edition cancels and replaces the first edition (ISO 14713-2:2009), which has been technically
revised. The main changes compared with the previous edition are as follows:
— minor technical changes have been made and two new notes have been added to Table 1;
— improvements have been made to the clarity of recommendations throughout Clause 6;
— extensive revisions have been made to the figures in Annex A;
— Tables A.1, A.2 and A.3 have been added in Annex A.
A list of all parts in the ISO 14713 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2019 – All rights reserved
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SIST EN ISO 14713-2:2020
ISO 14713-2:2019(E)
Introduction
The protection afforded by the hot dip galvanized coating to the article will depend upon the method
of application of the coating, the design of the article and the specific environment to which the article
is exposed. The hot dip galvanized article can be further protected by the application of additional
coatings (outside the scope of this document), such as organic coatings (paints or powder coatings).
When applied to hot dip galvanized articles, this combination of coatings is often known as a “duplex
system”.
Specific product-related requirements, for which specific standards could exist (e.g. for hot dip
galvanized coatings on tubes or fasteners), take precedence over these general recommendations.
© ISO 2019 – All rights reserved v
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SIST EN ISO 14713-2:2020
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SIST EN ISO 14713-2:2020
INTERNATIONAL STANDARD ISO 14713-2:2019(E)
Zinc coatings — Guidelines and recommendations for
the protection against corrosion of iron and steel in
structures —
Part 2:
Hot dip galvanizing
1 Scope
This document gives guidelines and recommendations for the general principles of design appropriate
to articles to be hot dip galvanized after fabrication (e.g. in accordance with ISO 1461) for the corrosion
protection of, for example, articles that have been manufactured in accordance with EN 1090-2.
This document does not apply to hot dip galvanized coatings applied to continuous wire or sheet (e.g. to
EN 10346).
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 8044, Corrosion of metals and alloys — Basic terms and definitions
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8044 and the following 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 http: //www .electropedia .org/
3.1
hot dip galvanizing
formation of a coating of zinc and/or zinc-iron alloys on iron and steel products by dipping prepared
steel or cast irons in the zinc melt
3.2
hot dip galvanized coating
coating obtained by hot dip galvanizing (3.1)
Note 1 to entry: The term “hot dip galvanized coating” is subsequently referred to as the “coating”.
3.3
duplex system
hot dip galvanized coating (3.2) with an additional paint or powder coating
© ISO 2019 – All rights reserved 1
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SIST EN ISO 14713-2:2020
ISO 14713-2:2019(E)
4 Design for hot dip galvanizing
4.1 General
It is essential that the design of any article required to be galvanized should take into account not
only the function of the article and its method of manufacture, but also the limitations imposed by the
finish. Annex A illustrates some of the important design features, some of which are specific to hot dip
galvanizing.
Some internal stresses in the articles to be galvanized will be relieved during the hot dip galvanizing
process and this can cause deformation or damage to the coated article. These internal stresses arise
from the finishing operations at the fabrication stage, such as cold forming, welding, oxy-cutting or
drilling, and from the residual stresses inherited from the rolling mill.
The purchaser should seek the advice of the galvanizer before designing or making a product that is
subsequently to be hot dip galvanized, as it can be necessary to adapt the construction of the article for
the hot dip galvanizing process.
4.2 Surface preparation
The design and the materials used should permit good surface preparation. This is essential for the
production of a high-quality coating (see 6.4).
Graphite exposed at the surface of iron castings interferes with wetting by molten metal and those
castings that have been annealed can have silica particles in the surface layers that have to be removed
in order to obtain a good-quality coating. Grit blasting is recommended both before and after annealing.
4.3 Procedures related to design considerations
The hot dip bath and associated plant should be of adequate capacity to process the articles to be hot dip
coated with zinc. Preferably, articles should be designed to enable coating in a single dipping operation.
Articles that are too large for the available baths may be partially immersed and then reversed for
length or depth, so that a complete coating is obtained. Partial immersion (and then dipping for a second
time to complete the coating) is less common than the single, complete immersion operation.
All work is secured during immersion in the baths. Arrangements for lifting and handling should be
made before articles are delivered to the galvanizer. When necessary, the customer should consult
the galvanizer and advise of any limitations (e.g. on the use of existing holes). Lifting lugs are often
incorporated to assist general handling.
Articles may be held in racks or jigs. Some contact marks can be visible after hot dip galvanizing in such
cases. The dipping operation involves vertical movement out of the bath, but the parts being withdrawn
may be inclined at an angle.
The processing sequence requires the circulation of air, pretreatment liquids and zinc to all surfaces
of the article. Air pockets prevent local surface preparation and give uncoated surfaces. Liquids in
enclosed air vaporize at the hot dip galvanizing temperature of about 450 °C and the force generated
can cause buckling or explosions. Excess zinc can adhere poorly, can look unattractive and is wasteful.
Suitable articles, e.g. heat exchangers and gas cylinders, can, if required, be hot dip galvanized on the
outside only. This involves special techniques and equipment (e.g. to push the article into the bath
against the buoyancy of the molten zinc) and a specialist galvanizer should be consulted in advance.
Hot dip galvanizing of hollow sections ensures protection of both internal and external surfaces. Small
amounts of trapped zinc ash can be unavoidable within hollow sections and, for certain shapes and
designs, cannot be removed.
2 © ISO 2019 – All rights reserved
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SIST EN ISO 14713-2:2020
ISO 14713-2:2019(E)
4.4 Design features
Preferred design features for articles to be hot dip galvanized are shown in Annex A.
WARNING — It is essential that sealed compartments be avoided or be vented, otherwise there
is a serious risk of explosion that could cause serious injury to operators. This aspect of design
shall be given careful consideration and is essential in order to maintain satisfactory standards
of health and safety for operators.
In addition to provision for venting and draining of tubular fabrications, holes also allow a coating to
be formed on the inside surfaces and therefore ensure better protection for the article. Occasionally, at
sufficiently high levels of residual stress in the article, stress relief can occur at the hot dip galvanizing
temperature. This is one of the main causes of unexpected distortion or cracking of the steel article.
Symmetrical sections are preferred and, as far as possible, large variations in thickness or cross-section,
e.g. thin sheet welded to thick angles, should be avoided. Welding and fabrication techniques should be
chosen to minimize the introduction of unbalanced stresses. Differential thermal expansion should be
minimized during welding and processing. Heat treatment can be desirable before hot dip galvanizing.
The purchaser should discuss with the galvanizer the requirements for coating and assembly of
fabricated articles before galvanizing. Compact sub-assemblies (which occupy minimum bath space)
are the most economical to galvanize. Welding is preferable before hot dip galvanizing, to ensure a
continuous hot dip galvanized coating over the weld.
Articles should be designed so as to assist the access and drainage of molten metal and so that air locks
are avoided. A smooth profile, avoiding unnecessary edges and corners, assists hot dip galvanizing.
This, combined with bolting after galvanizing, improves long-term corrosion resistance.
Holes that are necessary in structures for the hot dip galvanizing process are preferably made before
assembly and by cutting or grinding off corners of sections; this facilitates the absence of “pockets” in
which excess molten zinc can solidify. When already assembled, burning could be the optimum method
of producing holes, as the space available for drilling may not allow the hole to be close enough to the
edge or corners.
Internal venting of hollow sections should be avoided. If internal venting is unavoidable, it should
be agreed in advance with the galvanizer [see also ISO 1461:2009, A.2, e)] and the customer should
ensure that:
a) the holes are of maximum possible size;
b) provision for internal venting is adequately documented (e.g. by photography) before assembly.
4.5 Tolerances
The thickness of the coating is determined mainly by the nature and thickness of the steel. On mating
surfaces and at holes, extra tolerance should be provided to allow for the thickness of the coating metal.
For coatings on flat surfaces, an allowance of at least 1 mm has been found satisfactory. See ISO 1461
for definitions of significant surfaces and acceptance criteria for the coating. For threaded work, for
example, for hot dip galvanized and centrifuged nuts and bolts, current practices differ according to the
country. See 7.1.
5 Design for storage and transport
Hot dip galvanized articles should be stacked securely so that the articles can be handled, stored and
transported safely.
Where there is a specific need to minimize the development of wet-storage staining (primarily basic
zinc oxide and zinc hydroxide, formed on the surface of the galvanized coating during storage of articles
in humid conditions), this should be communicated by the purchaser to the galvanizer at the time of
ordering and any relevant control measures should be agreed upon.
© ISO 2019 – All rights reserved 3
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SIST EN ISO 14713-2:2020
ISO 14713-2:2019(E)
Such measures can include, for example, storage of articles such that free movement of air across the
surfaces of the article is allowed, the use of spacers to minimize contact areas on the work, chemical
post-treatment or avoidance of close nesting of work (where the design allows this). Shrink wrapping
can lead to water retention within the articles and subsequent wet-storage staining.
In accordance with ISO 1461, the presence of wet-storage staining is not a cause for rejection, provided
the coating thickness remains above the specified minimum requirements at the time of acceptance
inspection.
6 Effect of article condition on quality of hot dip galvanizing
6.1 General
Most steels can be hot dip galvanized in accordance with ISO 1461. This includes unalloyed carbon
steels (see, e.g., EN 10025-2), fine-grained steels (see, e.g., EN 10025-3 and EN 10025-4), quenched
and tempered steels, hollow sections that are hot finished (see, e.g., EN 10210-1), hollow sections that
are cold finished (see, e.g., EN 10219-1), reinforcement steels (see, e.g., EN 10080 and EN 10348-2),
fastener grade steels [see, e.g., ISO 898 (all parts)], grey cast iron (see, e.g., EN 1561) and malleable cast
iron (see, e.g., EN 1562). Where other ferrous metals are to be galvanized, adequate information or
samples should be provided by the purchaser for the galvanizer to decide whether these steels can be
satisfactorily galvanized. Sulfur-containing free-cutting steels are normally unsuitable. Stainless steels
are unsuitable.
6.2 Material composition
Certain elements, in particular silicon (Si) and phosphorus (P), in the steel surface can affect hot
dip galvanizing by prolonging the reaction between iron and molten zinc. Therefore, certain steel
compositions can achieve more consistent coatings with regard to appearance, thickness and
smoothness. The prior history of the steel (e.g. whether hot rolled or cold rolled) can also affect its
reaction with molten zinc. Where aesthetics are important or where particular coating thickness
or surface smoothness criteria exist, specialist advice on steel selection should be sought prior to
fabrication of the article or hot dip galvanizing.
Table 1 gives simplified guidance on steel compositions that are associated with certain typical coating
characteristics when galvanizing is carried out at temperatures of 440 °C to 460 °C.
4 © ISO 2019 – All rights reserved
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SIST EN ISO 14713-2:2020
ISO 14713-2:2019(E)
Table 1 — Coating characteristics related to steel composition
Category Typical levels of reactive Additional
...
SLOVENSKI STANDARD
oSIST prEN ISO 14713-2:2019
01-maj-2019
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NRQVWUXNFLMSURWLNRUR]LMLGHO 9URþHSRFLQNDYDQMH ,62',6
Zinc coatings - Guidelines and recommendations for the protection against corrosion of
iron and steel in structures - Part 2: Hot dip galvanizing (ISO/DIS 14713-2:2019)
Zinküberzüge - Leitfäden und Empfehlungen zum Schutz von Eisen- und
Stahlkonstruktionen vor Korrosion - Teil 2: Feuerverzinken (ISO/DIS 14713-2:2019)
Revêtements de zinc - Lignes directrices et recommandations pour la protection contre
la corrosion du fer et de l'acier dans les constructions - Partie 2: Galvanisation à chaud
(ISO/DIS 14713-2:2019)
Ta slovenski standard je istoveten z: prEN ISO 14713-2
ICS:
25.220.40 Kovinske prevleke Metallic coatings
91.080.10 Kovinske konstrukcije Metal structures
91.080.13 Jeklene konstrukcije Steel structures
oSIST prEN ISO 14713-2:2019 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
oSIST prEN ISO 14713-2:2019
---------------------- Page: 2 ----------------------
oSIST prEN ISO 14713-2:2019
DRAFT INTERNATIONAL STANDARD
ISO/DIS 14713-2
ISO/TC 107/SC 4 Secretariat: BSI
Voting begins on: Voting terminates on:
2019-03-08 2019-05-31
Zinc coatings — Guidelines and recommendations for
the protection against corrosion of iron and steel in
structures —
Part 2:
Hot dip galvanizing
Revêtements de zinc — Lignes directrices et recommandations pour la protection contre la corrosion du fer
et de l'acier dans les constructions —
Partie 2: Galvanisation à chaud
ICS: 25.220.40
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 14713-2:2019(E)
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. ISO 2019
---------------------- Page: 3 ----------------------
oSIST prEN ISO 14713-2:2019
ISO/DIS 14713-2:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 14713-2:2019
ISO/DIS 14713-2:2019(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Design for hot dip galvanizing . 2
4.1 General . 2
4.2 Surface preparation . 2
4.3 Procedures related to design considerations . 2
4.4 Design features . 3
4.5 Tolerances . 3
5 Design for storage and transport . 4
6 Effect of article condition on quality of hot dip galvanizing . 4
6.1 General . 4
6.1.1 Material composition . 4
6.1.2 Castings . 4
6.2 Surface condition . 5
6.3 Influence of steel surface roughness on the hot dip galvanized coating thickness . 6
6.4 Influence of thermal cutting processes and welding . 6
6.4.1 Thermal cutting . 6
6.4.2 Welding . 6
6.4.3 Free edges . 6
6.5 Effect of internal stresses in the steel article . 6
6.5.1 General. 6
6.5.2 Distortion cracking . 6
6.5.3 Hydrogen embrittlement . 7
6.5.4 Strain age embrittlement . . 7
6.5.5 Liquid metal assisted cracking (LMAC) or liquid metal embrittlement (LME) . 7
6.6 Large objects or thick steels . 8
6.7 Hot dip galvanizing practice . 8
7 Effect of hot dip galvanizing process on the article . 8
7.1 Dimensional tolerances on mating threads . 8
7.2 Effect of process heat . 8
8 After-treatments . 8
Annex A (informative) Preferred designs of articles for hot dip galvanizing .10
Bibliography .21
© ISO 2019 – All rights reserved iii
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oSIST prEN ISO 14713-2:2019
ISO/DIS 14713-2:2019(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International
Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies
casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 14713-2 was prepared by Technical Committee ISO/TC 107, Metallic and other inorganic coatings,
Subcommittee SC 4, Hot dip coatings (galvanized, etc.).
This second edition cancels and replaces ISO 14713-2:2009, which has been technically revised
ISO 14713 consists of the following parts, under the general title Zinc coatings — Guidelines and
recommendations for the protection against corrosion of iron and steel in structures:
— Part 1: General principles of design and corrosion resistance
— Part 2: Hot dip galvanizing
— Part 3: Sherardizing
The principal changes in this revised edition compared to ISO 14713-2:2009 are the following:
— Minor technical changes to Table 1 and addition of two new notes to Table 1.
— Improvements to the clarity of recommendations throughout Clause 6.
— Extensive revisions to the Figures contained in Annex A.
— Addition of Tables A.1, A.2 and A.3 in Annex A.
— Other minor technical and editorial changes.
iv © ISO 2019 – All rights reserved
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oSIST prEN ISO 14713-2:2019
DRAFT INTERNATIONAL STANDARD ISO/DIS 14713-2:2019(E)
Zinc coatings — Guidelines and recommendations for
the protection against corrosion of iron and steel in
structures —
Part 2:
Hot dip galvanizing
1 Scope
This part of ISO 14713 provides guidelines and recommendations regarding the general principles of
design which are appropriate for articles to be hot dip galvanized after fabrication (e.g., to ISO 1461) for
corrosion protection, for example, articles manufactured in accordance with EN 1090-2.
The protection afforded by the hot dip galvanized coating to the article will depend upon the method of
application of the coating, the design of the article and the specific environment to which the article is
exposed. The hot dip galvanized article can be further protected by application of additional coatings
(outside the scope of this part of ISO 14713), such as organic coatings (paints or powder coatings). When
applied to hot dip galvanized articles, this combination of coatings is often known as a “duplex system”.
Specific product-related requirements (e.g. for hot dip galvanized coatings on tubes or fasteners, etc.)
will take precedence over these general recommendations.
This standard does not apply to hot dip galvanized coatings applied to continuous sheet (e.g. to
EN 10346).
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 1461, Hot dip galvanized coatings on fabricated iron and steel articles — Specifications and test methods
ISO 8044, Corrosion of metals and alloys — Basic terms and definitions
ISO 2080, Metallic and other inorganic coatings — Surface treatment, metallic and other inorganic
coatings — Vocabulary
ISO 10684, Fasteners — Hot dip galvanized coatings
ISO 12944-5, Paints and varnishes — Corrosion protection of steel structures by protective paint systems —
Part 5: Protective paint systems
EN 10210-1, Hot finished structural hollow sections of non-alloy and fine grain steels — Part 1: Technical
delivery requirements
EN 10219-1, Cold formed welded structural hollow sections of non-alloy and fine grain steels — Part 1:
Technical delivery requirements
EN 10240, Internal and/or external protective coatings for steel tubes — Specification for hot dip galvanized
coatings applied in automatic plants
EN 1090-2:2018, Execution of steel structures and aluminium structures — Part 2: Technical requirements
for steel structures
© ISO 2019 – All rights reserved 1
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oSIST prEN ISO 14713-2:2019
ISO/DIS 14713-2:2019(E)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8044 and the following apply.
3.1
hot dip galvanizing
formation of a coating of zinc and/or zinc/iron alloys on iron and steel products by dipping prepared
steel or cast irons in the zinc melt
3.2
hot dip galvanized coating
coating obtained by hot dip galvanizing
Note 1 to entry: The term “hot dip galvanized coating” is subsequently referred to as the “coating”.
4 Design for hot dip galvanizing
4.1 General
It is essential that the design of any article required to be finished should take into account not only
the function of the article and its method of manufacture but also the limitations imposed by the
finish. Annex A illustrates some of the important design features, some of which are specific to hot dip
galvanizing.
Some internal stresses in the articles to be galvanized will be relieved during the hot dip galvanizing
process and this may cause deformation or damage of the coated article. These internal stresses arise
from the finishing operations at the fabrication stage, such as cold forming, welding, oxy-cutting or
drilling, and from the residual stresses inherited from the rolling mill. The purchaser should seek the
advice of the hot dip galvanizer before designing or making a product that is subsequently to be hot dip
galvanized, as it may be necessary to adapt the construction of the article for the hot dip galvanizing
process.
4.2 Surface preparation
The design and the materials used should permit good surface preparation. This is essential for the
production of a high-quality coating (see 6.2).
Graphite exposed at the surface of iron castings interferes with wetting by molten metal and those
castings that have been annealed may have silica particles in the surface layers which have to be
removed in order to obtain a good-quality hot dipped coating. Grit blasting is recommended both before
and after annealing.
4.3 Procedures related to design considerations
The hot dip bath and associated plant should be of adequate capacity to process the articles to be hot dip
coated with zinc. Preferably, articles should be designed to enable coating in a single dipping operation.
Articles that are too large for the available baths may be partially immersed and then reversed for
length or depth, so that a complete coating is obtained. Partial immersion (and then dipping for a second
time to complete the coating) is less common than the single, complete immersion operation.
All work has to be secured during immersion in the baths. Arrangements for lifting and handling
should be made before articles are delivered to the galvanizer. When necessary, the customer should
consult the galvanizer and advise any limitations (e.g. on the use of existing holes). Lifting lugs are often
incorporated to assist general handling.
Articles may be held in racks or jigs. Some contact marks may be visible after hot dip galvanizing in such
cases. The dipping operation involves vertical movement out of the bath, but the parts being withdrawn
may be inclined at an angle. The processing sequence requires circulation of air, pretreatment liquids
and zinc to all surfaces of the article. Air pockets prevent local surface preparation and give uncoated
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surfaces; liquids in enclosed air vaporize at the hot dip galvanizing temperature of about 450 °C and the
force generated can cause buckling or explosions; excess zinc may adhere poorly, may look unattractive
and is wasteful.
Suitable articles, e.g. heat exchangers and gas cylinders, may be hot dip galvanized on the outside
only. This involves special techniques and equipment (e.g. to push the article into the bath against the
buoyancy of the molten zinc) and a specialist galvanizer should be consulted in advance.
Hot dip galvanizing of hollow sections ensures protection of both internal and external surfaces. Small
amounts of trapped zinc ash may be unavoidable within hollow sections and, for certain shapes and
designs cannot be removed.
4.4 Design features
Preferred design features for articles to be hot dip galvanized are shown in Annex A.
WARNING — It is essential that sealed compartments be avoided or be vented, otherwise there
is a serious risk of explosion that may cause serious injury to operators. This aspect of design
shall be given careful consideration and is essential in order to maintain satisfactory standards
of health and safety for operators.
The provision of holes for venting and draining tubular fabrications also allows a coating to be
formed on the inside surfaces and therefore ensures better protection for the article. Occasionally, at
sufficiently high levels of residual stress in the article, stress relief may occur at the hot dip galvanizing
temperature. This is one of the main causes of unexpected distortion or cracking of the steel article.
Symmetrical sections are preferred and, as far as possible, large variations in thickness or cross-section,
e.g. thin sheet welded to thick angles, should be avoided, welding and fabrication techniques should
be chosen to minimize the introduction of unbalanced stresses and differential thermal expansion
should be minimized during welding and processing. Heat treatment may be desirable before hot
dip galvanizing. The purchaser should discuss with the galvanizer the requirements for coating and
assembly of fabricated articles. Compact sub-assemblies (which occupy minimum bath space) are most
economical to galvanize. Welding is preferable before hot dip galvanizing, to ensure a continuous hot
dip galvanized coating over the weld.
Articles should be designed so as to assist the access and drainage of molten metal and so that air locks
are avoided. A smooth profile, avoiding unnecessary edges and corners, assists hot dip galvanizing.
This, combined with bolting after galvanizing, improves long-term corrosion resistance.
Holes which are necessary in structures for the hot dip galvanizing process are preferably made before
assembly and by cutting or grinding off corners of sections; this facilitates the absence of “pockets” in
which excess molten zinc can solidify. When already assembled, burning may be the optimum method
of producing holes, as the space available for drilling may not allow the hole to be close enough to the
edge or corners.
Internal venting of hollow sections should be avoided. If internal venting is unavoidable, it shall be
agreed in advance with the galvanizer and the customer shall ensure that:
(1) the holes are of maximum possible size;
(2) provision for internal venting is adequately documented (e.g., by photography) before assembly.
4.5 Tolerances
The thickness of the hot dip coating is determined mainly by the nature and thickness of the steel.
On mating surfaces and at holes, extra tolerance should be provided to allow for the thickness of the
coating metal. For hot dip galvanized coatings on flat surfaces, an allowance of at least 1 mm has been
found satisfactory. See ISO 1461 for definitions of significant surfaces and acceptance criteria for the
coating. For threaded work, for example, for hot dip galvanized and centrifuged nuts and bolts, current
practices differ according to the country. See 7.1.
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5 Design for storage and transport
Hot dip galvanized articles should be stacked securely so that the articles can be handled, stored and
transported safely.
Where there is a specific need to minimize the development of wet-storage staining (primarily basic
zinc oxide and zinc hydroxide, formed on the surface of the galvanized coating during storage of articles
in humid conditions), this should be communicated by the purchaser to the galvanizer at the time of
ordering and any relevant control measures should be agreed upon.
Such measures might include, for example: storage of articles such that free movement of air across the
surfaces of the article is allowed; the use of spacers to minimize contact areas on the work; chemical
post-treatment, or avoidance of close nesting of work (where the design allows this). Shrink wrapping
may lead to water retention within the articles and subsequent wet-storage staining.
In accordance with ISO 1461, the presence of wet-storage staining shall not be a cause for rejection,
provided the coating thickness remains above the specified minimum requirements at the time of
acceptance inspection.
6 Effect of article condition on quality of hot dip galvanizing
6.1 General
Most steels can be hot dip galvanized according to ISO 1461. This includes unalloyed carbon steels (see
e.g. EN 10025-2), fine-grained steels (see e.g. EN 10025-3 and EN 10025-4), quenched and tempered
steels, hollow sections that are hot finished (see e.g. EN 10210-1), hollow sections that are cold finished
(see e.g. EN 10219-1), reinforcement steels (see e.g. EN 10080), fastener grade steels (see e.g. ISO 898),
grey cast iron (see e.g. EN 1561) and malleable cast iron (see e.g. EN 1562). Where other ferrous metals
are to be galvanized, adequate information or samples should be provided by the purchaser for the
galvanizer to decide whether these steels can be satisfactorily galvanized. Sulfur-containing free-
cutting steels are normally unsuitable.
6.1.1 Material composition
Certain elements, in particular silicon (Si) and phosphorus (P), in the steel surface can affect hot
dip galvanizing by prolonging the reaction between iron and molten zinc. Therefore, certain steel
compositions can achieve more consistent coatings with regard to appearance, thickness and
smoothness. The prior history of the steel (e.g. whether hot rolled or cold rolled) can also affect its
reaction with molten zinc. Where aesthetics are important or where particular coating thickness
or surface smoothness criteria exist, specialist advice on steel selection should be sought prior to
fabrication of the article or hot dip galvanizing.
Table 1 gives simplified guidance on steel compositions that are associated with certain typical coating
characteristics when galvanizing is carried out at temperatures of 440 °C to 460 °C.
6.1.2 Castings
Castings should be as free as possible from surface porosity and shrinkage holes and should be cleaned
by grit blasting, electrolytic pickling or by other methods especially suitable for castings. Conventional
hydrochloric acid pickling does not remove mould-sand deposits, graphite or temper carbon from
the surface of cast iron. Grit blasting is necessary to remove these contaminants. Surface cleaning of
complex shapes can be undertaken by specialist galvanizing companies using hydrofluoric acid. Care
needs to be exercised in the design of cast-iron sections. Small castings of simple shape and solid cross-
section do not present problems for galvanizing, provided that the material and surface condition are
suitable. Larger castings should have a balanced design with uniform section thicknesses to avoid
distortion and cracking due to thermal stress. Large fillet radii and pattern numbers should be used
and sharp corners and deep recesses avoided.
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The rough surface finish which castings tend to possess may result in thicker galvanized coatings than
on rolled articles.
NOTE Castings can take several forms:
— grey iron castings: grey iron has a carbon content of greater than 2 %, the majority of which is graphite in
flake form;
— spheroidal graphite (SG) castings: similar to grey iron in many aspects of composition but with carbon
present primarily as graphite in spheroidal form, initiated by additions of magnesium or cerium;
— malleable iron castings: black-heart, white-heart and pearlitic. The toughness and workability are derived
from annealing processes and no primary graphite is permissible.
Table 1 — Coating characteristics related to steel composition
Category Typical levels of reactive Additional information Typical coating characteris-
elements tics
A ≤ 0,03 % Si and < 0,02 % P See Note 1 and Note 4 Coating has a shiny appear-
ance with a finer texture. Coat-
ing structure includes outer
zinc layer.
B ≥ 0,14 % Si to 0,25 % Si Other elements may also affect Coating can have shiny or matt
steel reactivity. In particular, appearance. Coating structure
phosphorus levels greater than can include outer zinc layer
0,035 % will give increased or iron-zinc alloy can extend
reactivity. through to the coating surface
depending on steel composition.
C > 0,03 % Si to < 0,14 % Si Excessively thick coatings may Coating has a darker appear-
be formed. ance with a coarser texture.
Iron/zinc alloys dominate
D > 0,25 % Si Coating thickness increases
coating structure and often
with increasing silicon content.
extend to the coating surface,
with reduced resistance to
handling damage.
NOTE 1 Steels with compositions satisfying the formula Si ≤ 0,03% and Si + 2,5P ≤ 0,09 % are also expected to exhibit
these characteristics. For cold rolled steels, these characteristics are expected to be observed when the steel composition
satisfies the formula Si + 2,5P ≤ 0,04 %.
NOTE 2 The presence of alloying elements (e.g. nickel or aluminium) in the zinc melt can have a significant effect on
the coating characteristics indicated in this table. This table does not provide relevant guidance for high-temperature
galvanizing (i.e., immersion in molten zinc at 530 °C to 560 °C).
NOTE 3 The steel compositions indicated in this table will vary under the influence of other factors (e.g., hot rolling) and
the boundaries of each range will vary accordingly.
NOTE 4 Steels with compositions < 0,01 % silicon that also have aluminium contents > 0,035 % can exhibit lower reactivity
that could result in a lower than expected coating thickness. These steels might exhibit reduced levels of coating cohesion.
NOTE 5 The design of the article to be galvanized may also influence coating characteristics.
6.2 Surface condition
The surface of the basis metal should be clean before dipping into the molten zinc. Degreasing and
pickling in acid are the recommended methods of cleaning the surface. Excessive pickling should be
avoided. Surface contamination that cannot be removed by pickling, e.g. carbon films (such as rolling oil
residues)
...
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