ISO 4998:2023

ISO /FDIS 4998:2022(E)
ISO TC 17/SC 12
Date: 2022-09-1310-17
Secretariat: JISC
Steel sheet, zinc-coated and zinc-iron alloy-coated by the continuous hot-dip process, of
structural quality

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ISO/FDIS 4998:2022(E)
© ISO 2022
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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2022 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/FDIS 4998:2022(E)
Contents
Foreword . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Dimensions . 2
5 Conditions of manufacture . 3
5.1 Steelmaking . 3
5.2 Chemical composition . 3
5.3 Chemical analysis . 3
5.3.1 Heat analysis . 3
5.3.2 Product analysis . 3
5.4 Mechanical properties . 4
5.5 Coating . 4
5.5.1 Coating mass . 4
5.5.2 Coating adherence . 5
5.6 Weldability . 6
5.7 Painting . 6
5.8 Surface treatment . 6
5.8.1 Mill passivation . 6
5.8.2 Mill phosphating . 6
5.8.3 Oiling . 6
5.9 Dimensional and shape tolerance . 7
6 Sampling . 7
6.1 Chemical composition . 7
6.2 Tensile test . 7
6.3 Coating tests . 7
6.3.1 Coating mass . 7
6.3.2 Triple-spot test . 7
6.3.3 Single-spot test . 7
6.3.4 Coating adherence . 7
7 Test methods . 7
7.1 Tensile test . 7
7.2 Coating properties . 8
7.2.1 Coating mass . 8
7.2.2 Coating adherence . 8
8 Designation system . 8
8.1 General . 8
8.2 Coating type . 8
8.3 Coating mass . 8
8.4 Coating finish condition . 8
8.5 Surface treatments . 9
8.6 Example . 9
9 Retests . 9
9.1 Machining and flaws . 9
9.2 Elongation . 9
© ISO 2022 – All rights reserved iii

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ISO/FDIS 4998:2022(E)
9.3 Additional tests . 9
10 Resubmission . 9
11 Workmanship .10
12 Inspection and acceptance .10
13 Coil size .10
14 Marking .10
15 Information to be supplied by the purchaser .11
Annex A (normative) Orders requiring base-metal thickness .12
Bibliography .14

iv © ISO 2022 – All rights reserved

---------------------- Page: 4 ----------------------
ISO/FDIS 4998:2022(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 17, Steel, Subcommittee SC 12, Continuous
mill flat rolled products.
This seventh edition cancels and replaces the sixth edition (ISO 4998:2014), which has been technically
revised.
The main changes are as follows:
— update of terms and definitions;
— Addition of NOTE to inform that chromate-free treatment is available for use as mill passivation;
— addition of coating mass designations.
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.
© ISO 2022 – All rights reserved v

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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 4998:2022(E)

Steel sheet, zinc-coated and zinc-iron alloy-coated by the
continuous hot-dip process, of structural quality
1 Scope
This document specifies the requirements for steel sheet, zinc-coated and zinc-iron alloy-coated by the
continuous hot-dip process, of structural quality.
The product is intended for applications where resistance to corrosion is of prime importance.
The steel sheet is produced in a number of grades, coating masses, ordering conditions, and surface
treatments.
This document does not cover steel sheet designated as commercial quality, or drawing quality, which
[2]
are covered in ISO 3575 .
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 1460, Metallic coatings — Hot dip galvanized coatings on ferrous materials — Gravimetric
determination of the mass per unit area
ISO 2178, Non-magnetic coatings on magnetic substrates — Measurement of coating thickness — Magnetic
method
ISO 3497, Metallic coatings — Measurement of coating thickness — X-ray spectrometric methods
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
ISO 7438, Metallic materials — Bend test
ISO 16163, Continuously hot-dipped coated steel sheet products — Dimensional and shape tolerances
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
3.1
zinc-coated steel sheet
product obtained by hot-dip coating of cold-reduced sheet coils or hot-rolled descaled sheet coils on a
continuous zinc-coating line
© ISO 2022 – All rights reserved 1

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ISO/FDIS 4998:2022(E)
3.2
zinc-iron alloy-coated steel sheet
product obtained by processing the zinc-coated steel sheet so that the coating formed on the base-metal
is composed of zinc-iron alloys
Note 1 to entry: This product, designated ZF, is not spangled, is normally dull in appearance, and, for some
applications, can be suitable for immediate painting without further treatment, except normal cleaning. Zinc-iron
alloy coatings can powder during severe forming.
3.3
normal coating
coating formed as a result of unrestricted growth of zinc crystals during normal solidification
Note 1 to entry: This coating has a metallic lustre and is the type normally furnished for a wide variety of
applications. It can be furnished as S (normal coating, with skin pass) or N (normal coating, no skin pass); however,
it can be variable in appearance and is not suitable for decorative painting.
3.4
minimized spangle
finish obtained by restricting normal spangle formation during the solidification of the zinc
Note 1 to entry: This product can have some lack of uniformity in surface appearance within a coil, or from coil to
coil.
3.5
differential coating
coating deliberately produced to have a different coating mass on each surface
3.6
skin pass
light cold-rolling of the product
Note 1 to entry: The purpose of the skin passing is one or more of the following: to minimize the appearance of coil
breaks, stretcher strains and fluting; to control the shape; and to obtain the required surface finish.
Note 2 to entry: Some increase in hardness and some loss in ductility will result from skin passing.
3.7
lot
up to a specified quantity of steel sheet of the same designation rolled to the same thickness and coating
condition
3.8
coating mass
2
total amount of coating on both sides of the sheet, expressed in grams per square metre (g/m ) of sheet
4 Dimensions
4.1 Zinc-coated and zinc-iron alloy-coated structural quality steel sheet is produced in thicknesses from
0,25 mm to 5 mm inclusive after coating, and in widths of 600 mm and over in coils and cut lengths. Zinc-
coated and zinc-iron alloy-coated steel sheet less than 600 mm wide, slit from wide sheet, is considered
as sheet.
2© ISO 2022 – All rights reserved © ISO 2022 – All rights reserved

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ISO/FDIS 4998:2022(E)
NOTE Thicknesses less than 0,4 mm might not be available in grades 220, 250, 280, and 320.
4.2 The thickness of zinc-coated and zinc-iron alloy-coated steel sheet may be specified as a combination
of the base-metal and metallic coating, or as the base-metal alone. The purchaser shall indicate on the
order which method of specifying thickness is required. In the event that the purchaser does not indicate
any preference, the thickness as a combination of the base-metal and coating will be provided. Annex A
describes the requirements for specifying the thickness as the base-metal alone.
5 Conditions of manufacture
5.1 Steelmaking
Unless otherwise agreed by the interested parties, the processes used in making the steel and in
manufacturing zinc-coated and zinc-iron alloy-coated steel sheet of structural quality are left to the
discretion of the manufacturer. On request, the purchaser shall be informed of the steelmaking process
being used.
5.2 Chemical composition
The chemical composition (heat analysis) shall conform to the requirements given in Tables 1 and 2.
5.3 Chemical analysis
5.3.1 Heat analysis
An analysis of each heat shall be made by the manufacturer in order to determine conformity with the
requirements given in Tables 1 and 2. On request, a report of the heat analysis shall be made available to
the purchaser or the purchaser’s representative. Each of the elements listed in Tables 1 and 2 shall be
included in the report of the heat analysis. When the amount of copper, nickel, chromium or molybdenum
present is less than 0,02 %, the analysis may be reported as “<0,02 %”.
5.3.2 Product analysis
A product analysis may be made by the purchaser in order to verify the specified analysis of the product
and shall take into consideration any normal heterogeneity. The product analysis tolerances shall be in
accordance with Tables 2 and 3.
Table 1 — Chemical composition (heat analysis)
Mass fraction in per cent
Element Maximum of specified element
C 0,25
Mn 1,70
a
0,05
P
S 0,035
a
  Grades 250 and 280: P − 0,10 % max.; Grade 350: P − 0,20 % max.
Table 2 — Limits on additional chemical elements
Mass fraction in per cent
a a a, b a, b c c c
Cu Ni Cr Mo Nb V Ti
Element
max. max. max. max. max. max. max.
© ISO 2022 – All rights reserved 3

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ISO/FDIS 4998:2022(E)
Heat analysis 0,20 0,20 0,15 0,06 0,008 0,008 0,008
Product analysis 0,23 0,23 0,19 0,07 0,018 0,018 0,018
a
  The sum of copper, nickel, chromium, and molybdenum shall not exceed 0,50 % on heat analysis. When one or more of these
elements are specified, the sum does not apply, in which case only the individual limits on the remaining elements apply.
b
  The sum of chromium and molybdenum shall not exceed 0,16 % on heat analysis. When one or more of these elements are
specified, the sum does not apply, in which case only the individual limits on the remaining elements apply.
c
  Heat analysis greater than 0,008 % may be supplied after agreement between the producer and purchaser.
Table 3 — Product analysis tolerances for Table 1
Mass fraction in per cent
Maximum Tolerance over
Element
of specified element maximum specified
C 0,25 0,04
Mn 1,70 0,05
P
...

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 4998
ISO/TC 17/SC 12
Steel sheet, zinc‐coated and zinc‐iron
Secretariat: JISC
alloy‐coated by the continuous hot‐dip
Voting begins on:
2022-11-01 process, of structural quality
Voting terminates on:
2022-12-27
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 SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 4998:2022(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. © ISO 2022

---------------------- Page: 1 ----------------------
ISO/FDIS 4998:2022(E)
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 4998
ISO/TC 17/SC 12
Steel sheet, zinc‐coated and zinc‐iron
Secretariat: JISC
alloy‐coated by the continuous hot‐dip
Voting begins on:
process, of structural quality
Voting terminates on:
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022
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.
RECIPIENTS OF THIS DRAFT ARE INVITED TO
ISO copyright office
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
CP 401 • Ch. de Blandonnet 8
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
CH-1214 Vernier, Geneva
DOCUMENTATION.
Phone: +41 22 749 01 11
IN ADDITION TO THEIR EVALUATION AS
Reference number
Email: copyright@iso.org
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/FDIS 4998:2022(E)
Website: www.iso.org
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
Published in Switzerland
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN­
DARDS TO WHICH REFERENCE MAY BE MADE IN
ii
  © ISO 2022 – All rights reserved
NATIONAL REGULATIONS. © ISO 2022

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ISO/FDIS 4998:2022(E)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Dimensions .2
5 Conditions of manufacture .3
5.1 Steelmaking . 3
5.2 Chemical composition . 3
5.3 Chemical analysis . 3
5.3.1 Heat analysis . 3
5.3.2 Product analysis . 3
5.4 Mechanical properties . 4
5.5 Coating . 4
5.5.1 Coating mass . 4
5.5.2 Coating adherence. 5
5.6 Weldability . 6
5.7 Painting . 6
5.8 Surface treatment . 6
5.8.1 Mill passivation . 6
5.8.2 Mill phosphating . 6
5.8.3 Oiling . 7
5.9 Dimensional and shape tolerances . 7
6 Sampling . 7
6.1 Chemical composition . 7
6.2 Tensile test . 7
6.3 Coating tests . 7
6.3.1 Coating mass . 7
6.3.2 Triple­spot test . 7
6.3.3 Single­spot test . 7
6.3.4 Coating adherence. 8
7 Test methods . 8
7.1 Tensile test . 8
7.2 Coating properties. 8
7.2.1 Coating mass . 8
7.2.2 Coating adherence. 8
8 Designation system . 8
8.1 General . 8
8.2 Coating type . 8
8.3 Coating mass . 8
8.4 Coating finish condition . 9
8.5 Surface treatments . 9
8.6 Example . 9
9 Retests . 9
9.1 Machining and flaws . . 9
9.2 Elongation . 10
9.3 Additional tests . 10
10 Resubmission.10
11 Workmanship .10
12 Inspection and acceptance .10
iii
© ISO 2022 – All rights reserved

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ISO/FDIS 4998:2022(E)
13 Coil size .10
14 Marking . .11
15 Information supplied by the purchaser .11
Annex A (normative) Orders requiring base‐metal thickness .13
Bibliography .14
iv
  © ISO 2022 – All rights reserved

---------------------- Page: 4 ----------------------
ISO/FDIS 4998:2022(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 non­governmental, 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 17, Steel, Subcommittee SC 12, Continuous
mill flat rolled products.
This seventh edition cancels and replaces the sixth edition (ISO 4998:2014), which has been technically
revised.
The main changes are as follows:
— update of terms and definitions;
— addition of coating mass designations.
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.
v
© ISO 2022 – All rights reserved

---------------------- Page: 5 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 4998:2022(E)
Steel sheet, zinc‐coated and zinc‐iron alloy‐coated by the
continuous hot‐dip process, of structural quality
1 Scope
This document specifies the requirements for steel sheet, zinc-coated and zinc-iron alloy-coated by the
continuous hot-dip process, of structural quality.
The product is intended for applications where resistance to corrosion is of prime importance.
The steel sheet is produced in a number of grades, coating masses, ordering conditions, and surface
treatments.
This document does not cover steel sheet designated as commercial quality, or drawing quality, which
[2]
are covered in ISO 3575 .
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 1460, Metallic coatings — Hot dip galvanized coatings on ferrous materials — Gravimetric
determination of the mass per unit area
ISO 2178, Non-magnetic coatings on magnetic substrates — Measurement of coating thickness — Magnetic
method
ISO 3497, Metallic coatings — Measurement of coating thickness — X-ray spectrometric methods
ISO 6892­1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
ISO 7438, Metallic materials — Bend test
ISO 16163, Continuously hot-dipped coated steel sheet products — Dimensional and shape tolerances
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
zinc‐coated steel sheet
product obtained by hot-dip coating of cold-reduced sheet coils or hot-rolled descaled sheet coils on a
continuous zinc­coating line
1
© ISO 2022 – All rights reserved

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ISO/FDIS 4998:2022(E)
3.2
zinc‐iron alloy‐coated steel sheet
product obtained by processing the zinc-coated steel sheet so that the coating formed on the base-metal
is composed of zinc-iron alloys
Note 1 to entry: This product, designated ZF, is not spangled, is normally dull in appearance, and, for some
applications, can be suitable for immediate painting without further treatment, except normal cleaning. Zinc-
iron alloy coatings can powder during severe forming.
3.3
normal coating
coating formed as a result of unrestricted growth of zinc crystals during normal solidification
Note 1 to entry: This coating has a metallic lustre and is the type normally furnished for a wide variety
of applications. It can be furnished as S (normal coating, with skin pass) or N (normal coating, no skin pass);
however, it can be variable in appearance and is not suitable for decorative painting.
3.4
minimized spangle
finish obtained by restricting normal spangle formation during the solidification of the zinc
Note 1 to entry: This product can have some lack of uniformity in surface appearance within a coil, or from coil
to coil.
3.5
differential coating
coating deliberately produced to have a different coating mass on each surface
3.6
skin pass
light cold­rolling of the product
Note 1 to entry: The purpose of the skin passing is one or more of the following: to minimize the appearance of
coil breaks, stretcher strains and fluting; to control the shape; and to obtain the required surface finish.
Note 2 to entry: Some increase in hardness and some loss in ductility will result from skin passing.
3.7
lot
up to a specified quantity of steel sheet of the same designation rolled to the same thickness and coating
condition
3.8
coating mass
2
total amount of coating on both sides of the sheet, expressed in grams per square metre (g/m ) of sheet
4 Dimensions
4.1 Zinc-coated and zinc-iron alloy-coated structural quality steel sheet is produced in thicknesses
from 0,25 mm to 5 mm inclusive after coating, and in widths of 600 mm and over in coils and cut
lengths. Zinc-coated and zinc-iron alloy-coated steel sheet less than 600 mm wide, slit from wide sheet,
is considered as sheet.
NOTE Thicknesses less than 0,4 mm might not be available in grades 220, 250, 280, and 320.
4.2 The thickness of zinc-coated and zinc-iron alloy-coated steel sheet may be specified as a
combination of the base­metal and metallic coating, or as the base­metal alone. The purchaser shall
indicate on the order which method of specifying thickness is required. In the event that the purchaser
does not indicate any preference, the thickness as a combination of the base-metal and coating will be
provided. Annex A describes the requirements for specifying the thickness as the base-metal alone.
2
  © ISO 2022 – All rights reserved

---------------------- Page: 7 ----------------------
ISO/FDIS 4998:2022(E)
5 Conditions of manufacture
5.1 Steelmaking
Unless otherwise agreed by the interested parties, the processes used in making the steel and in
manufacturing zinc-coated and zinc-iron alloy-coated steel sheet of structural quality are left to the
discretion of the manufacturer. On request, the purchaser shall be informed of the steelmaking process
being used.
5.2 Chemical composition
The chemical composition (heat analysis) shall conform to the requirements given in Tables 1 and 2.
5.3 Chemical analysis
5.3.1 Heat analysis
An analysis of each heat shall be ma
...