ISO 15211:2022
(Main)Steel sheet, twin-roll cast, zinc-coated by the continuous hot-dip process, of structural quality and high strength
Steel sheet, twin-roll cast, zinc-coated by the continuous hot-dip process, of structural quality and high strength
This document specifies the requirements for steel sheet, in coils and cut length, metallic-coated by the continuous hot-dip zinc-coated twin-roll cast process, of structural and high strength quality. The product is intended for applications requiring corrosion resistance, and paintability. The steel sheet is produced in a number of grades, coating masses, surface treatments and ordering conditions.
Tôles coulées entre cylindres et galvanisées en continu par immersion à chaud, de qualité destinée à la construction et en acier à haute résistance
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INTERNATIONAL ISO
STANDARD 15211
Second edition
2022-02
Steel sheet, twin-roll cast, zinc-coated
by the continuous hot-dip process, of
structural quality and high strength
Tôles coulées entre cylindres et galvanisées en continu par immersion
à chaud, de qualité destinée à la construction et en acier à haute
résistance
Reference number
ISO 15211:2022(E)
© ISO 2022
---------------------- Page: 1 ----------------------
ISO 15211:2022(E)
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.
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
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ISO 15211:2022(E)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Dimensions .2
5 Conditions of manufacture .2
5.1 Steelmaking . 2
5.2 Chemical composition . 2
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 . 6
5.5.1 Coating mass . 6
5.5.2 Coating adherence. 7
5.6 Weldability . 8
5.7 Painting . 8
5.8 Surface treatment . 8
5.8.1 Mill passivation . 8
5.8.2 Mill phosphating . 8
5.8.3 Oiling . 8
5.9 Coated coil joining . 9
5.10 Dimensional and shape tolerances . 9
6 Sampling . 9
6.1 Tensile test . 9
6.2 Coating tests . 9
6.2.1 Coating mass . 9
6.2.2 Triple-spot test . 9
6.2.3 Single-spot test . 9
6.2.4 Coating adherence. 9
7 Test methods .10
7.1 Tensile test . 10
7.2 Coating properties. 10
7.2.1 Coating mass . 10
7.2.2 Coating adherence. 10
8 Designation system .10
8.1 General . 10
8.2 Coating type . 10
8.3 Coating mass . 10
8.4 Coating finish condition . 11
8.5 Surface treatment . 11
8.6 Base-metal grade . 11
8.7 Examples . 11
9 Retests .12
9.1 Machining and flaws . .12
9.2 Elongation .12
9.3 Additional tests . 12
10 Resubmission.12
11 Workmanship .12
12 Inspection and acceptance .12
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ISO 15211:2022(E)
13 Coil Size .13
14 Marking . .13
15 Information supplied by the purchaser .13
Annex A (normative) Orders requiring base-metal thickness .15
Bibliography .16
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ISO 15211:2022(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 second edition cancels and replaces the first edition (ISO 15211:2012), which has been technically
revised.
The main changes are as follows:
— update of Clause 3;
— modification of the title of Clause 4.
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
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INTERNATIONAL STANDARD ISO 15211:2022(E)
Steel sheet, twin-roll cast, zinc-coated by the continuous
hot-dip process, of structural quality and high strength
1 Scope
This document specifies the requirements for steel sheet, in coils and cut length, metallic-coated by the
continuous hot-dip zinc-coated twin-roll cast process, of structural and high strength quality.
The product is intended for applications requiring corrosion resistance, and paintability.
The steel sheet is produced in a number of grades, coating masses, surface treatments and ordering
conditions.
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
continuous hot-dip 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
3.2
normal spangle
finish obtained 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 S (normal spangle with skin pass) or N (normal spangle, no skin pass), however,
it can be variable in appearance and not suitable for decorative paintings.
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ISO 15211:2022(E)
3.3
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.
3.4
differential coating
coating deliberately produced to have a different coating mass on each surface
3.5
skin pass
light cold rolling of the product
Note 1 to entry: The purpose of skin passing is one or more of the following: to minimize the appearance of coil
breaks, stretcher strains and fluting; to control the shape or to obtain the required surface finish.
Note 2 to entry: Some increase in hardness and some loss in ductility will result from skin passing.
3.6
twin-roll cast steel sheet
steel sheet produced by casting to near final thickness directly from the liquid metal with minimal hot
rolling to achieve the final thickness
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 zinc on both surfaces of the sheet, expressed in grams per square meter (g/m ) of sheet
4 Dimensions
Zinc-coated structural and high strength quality twin-roll cast steel sheet is produced in thicknesses
up to 2,0 mm, inclusive, after zinc coating, and in widths up to 2 000 mm in coils and cut lengths. Zinc-
coated twin-roll cast steel sheet less than 600 mm wide, slit from wide sheet, is considered as sheet.
The thickness of zinc-coated twin-roll cast steel sheet may be specified as a combination of the base-
metal and metallic coating or base-metal alone. The purchaser shall indicate on the order which method
of specifying thickness is required. If the purchaser does not indicate any preference, the thickness as
a combination of the base-metal and coating shall be provided. Annex A describes the requirements for
specifying the thickness as 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 steel sheet are left to the discretion of the manufacturer. Upon 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, 2 and 3.
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ISO 15211:2022(E)
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, 2 and 3. 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, 2
and 3 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 3 and 4.
Table 1 — Chemical composition (heat analysis) for structural quality steel sheet
Mass fractions in percent
Base-metal
C Mn P S
a
Si
grade designa-
max. max. max. max.
tion
HR 275
HR 340
HR 380
0,25 1,35 0,040 0,035 –
HR 410
HR 480
HR 550
a
“–” indicates that there is no requirement, but the analysis shall be reported.
Table 2 — Chemical composition (heat analysis) for high strength steel sheet
Mass fractions in percent
a d d d a
Base-metal C Mn P S Si V Ti Nb N
Class
grade desig- max. max. max. max. min. min. min.
nation
b
1 0,22 1,35 0,04 0,04 – 0,008 0,008 0,008 –
HSS 310
2 0,15 1,35 0,04 0,04 – 0,008 0,008 0,008 –
b
1 0,23 1,35 0,04 0,04 – 0,008 0,008 0,008 –
HSS 340
2 0,15 1,35 0,04 0,04 – 0,008 0,008 0,008 –
b
1 0.25 1,35 0,04 0,04 – 0,008 0,008 0,008 –
HSS 380
2 0,15 1,35 0,04 0,04 – 0,008 0,008 0,008 –
1 0,26 1,50 0,04 0,04 – 0,008 0,008 0,008 –
HSS 410
2 0,15 1,50 0,04 0,04 – 0,008 0,008 0,008 –
a
“–” indicates that there is no requirement, but the analysis shall be reported.
b
For each reduction of 0,01 % below the specified carbon maximum, an increase of 0,06 % manganese above the
specified maximum shall be permitted up to a maximum of 1,50 %.
c
The purchaser has the option of restricting the nitrogen content. It should be noted that, depending on the microalloying
scheme (for example use of vanadium) of the producer, nitrogen is permitted as a deliberate addition. Consideration should
be given to the use of nitrogen-binding elements (for example vanadium and titanium).
d
The producer shall add at least one or more of the elements V, Ti or Nb.
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ISO 15211:2022(E)
Table 2 (continued)
a d d d a
Base-metal C Mn P S Si V Ti Nb N
Class
grade desig- max. max. max. max. min. min. min.
nation
c
1 0,26 1,50 0,04 0,04 – 0,008 0,008 0,008 –
HSS 450
c
2 0,15 1,50 0,04 0,04 – 0,008 0,008 0,008 –
c
1 0,26 1,65 0,04 0,04 – 0,008 0,008 0,008 –
HSS 480
c
2 0,15 1,65 0,04 0,04 – 0,008 0,008 0,008 –
c
1 0,26 1,65 0,04 0,04 – 0,008 0,008 0,008 –
HSS 550
c
2 0,15 1,65 0,04 0,04 – 0,008 0,008 0,008 –
a
“–” indicates that there is no requirement, but the analysis shall be reported.
b
For each reduction of 0,01 % below the specified carbon maximum, an increase of 0,06 % manganese above the
specified maximum shall be permitted up to a maximum of 1,50 %.
c
The purchaser has the option of restricting the nitrogen content. It should be noted that, depending on the microalloying
scheme (for example use of vanadium) of the producer, nitrogen is permitted as a deliberate addition. Consideration should
be given to the use of nitrogen-binding elements (for example vanadium and titanium).
d
The producer shall add at least one or more of the elements V, Ti or Nb.
Table 3 — Limits on additional chemical elements for structural quality steel sheet
Mass fractions in percent
Cu Ni Cr Mo Nb V Ti
Element
max. max. max. max. max. max. max.
Heat analysis 0,50 0,30 0,30 0,15 0,008 0,008 0,008
Product analysis 0,53 0,33 0,34 0,16 0,018 0,018 0,018
Table 4 — Product analysis tolerances
Mass fractions in percent
Element Maximum of specified element Tolerance over the maximum speci-
fied
C 0,26 0,04
Mn 1,65 0,05
P 0,04 0,01
S 0,04 0,01
NOTE The above maximum tolerance is the allowable excess over the requirements of the heat analysis specified in
Tables 1 and 2.
5.4 Mechanical properties
The mechanical properties for structural quality steel sheet and high strength steel sheet shall be as
shown in Tables 5 and 6.
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ISO 15211:2022(E)
Table 5 — Mechanical properties for structural quality steel sheet
b
A
a
R R
min.
eL m
Base-metal grade
min. min.
%
designation
MPa MPa e ≤ 2 mm
L = 50 mm L = 80 mm
o o
HR 275 275 380 15 14
HR 340 340 340 9 8
HR 380 380 380 8 7
HR 410 410 410 7 6
HR 480 480 480 6 5
HR 550 550 550 5 4
Key
R : lower yield strength
eL
R : tensile strength
m
A: percentage elongation after fracture
L : gauge length on original test piece
o
e: thickness of steel sheet, in millimetre(s)
2
NOTE 1 MPa = 1 N/mm
a
The yield strength may be measured either by 0,5 % elongation proof stress, R (proof strength under load) or by
t0,5
0,2 % offset, R , where a definite yield strength phenomenon is not present.
p0,2
b
Use either L = 50 mm or L = 80 mm to measure elongation. For materials up to and including 0,6 mm in thickness, the
o o
elongation values in this table shall be reduced by 2.
Table 6 — Mechanical properties for high strength steel sheet
b
A
a
R R
min.
eL m
Base-metal
grade desig- Class min. min.
%
nation
MPa MPa e ≤ 2 mm
L = 50 mm L = 80 mm
o o
1 310 410 18 17
HSS 310
2 310 380 18 17
1 340 450 15 14
HSS 340
2 340 410 15 14
Key
R : lower yield strength
eL
R : tensile strength
m
A: percentage elongation after fracture
L : gauge length on original test piece
o
e: thickness of steel sheet, in millimetre(s)
2
NOTE 1 MPa = 1 N/mm
a
The yield strength may be measured either by 0,5 % elongation proof stress, R (proof strength under load) or by
t0,5
0,2 % offset, R , where a definite yield strength phenomenon is not present.
p0,2
b
For thicknesses up to 2 mm, use either L = 50 mm or L = 80 mm. In cases of dispute, however, only the results obtained
o o
on a 50 mm test piece shall be valid.
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ISO 15211:2022(E)
Table 6 (continued)
b
A
a
R R
min.
eL m
Base-metal
grade desig- Class min. min.
%
nation
MPa MPa e ≤ 2 mm
L = 50 mm L = 80 mm
o o
1 380 480 13 12
HSS 380
2 380 450 13 12
1 410 520 11 10
HSS 410
2 410 480 11 10
1 450 550 10 9
HSS 450
2 450 520 10 9
1 480 585 8 7
HSS 480
2 480 550 8 7
1 550 565 7 6
HSS 550
2 550 620 7 6
Key
R : lower yield strength
eL
R : tensile strength
m
A: percentage elongation after fracture
L : gauge length on original test piece
o
e: thickness of steel sheet, in millimetre(s)
2
NOTE 1 MPa = 1 N/mm
a
The yield strength may be measured either by 0,5 % elongation proof stress, R (proof strength under load) or by
t0,5
0,2 % offset, R , where a definite yield strength phenomenon is not present.
p0,2
b
For thicknesses up to 2 mm, use either L = 50 mm or L = 80 mm. In cases of dispute, however, only the results obtained
o o
on a 50 mm test piece shall be valid.
5.5 Coating
5.5.1 Coating mass
The coating mass shall conform to the limits for the coating designations shown in Table 7. The
interested parties shall agree upon the coating mass of differentially coated products. If a maximum
coating mass is required, the manufacturer shall be notified at the time of ordering.
Table 7 — Coating mass (total both sides)
Minimum check limit
Coating mass
Triple-spot test Single-spot test
designation
2 2
g/m g/m
a a
Z001 no minimum no minimum
NOTE 1 Because of the many variables and changing conditions that are characteristic of continuous zinc coating, the
coating mass is not always evenly divided between the two surfaces of a zinc-coated sheet; neither is the coating evenly
distributed from edge to edge. However, it can normally be expected that not less than 40 % of the single spot check limit
will be found on either surface.
NOTE 2 The coating thickness can be estimated from the coating mass using the following relationship:
2
100 g/m total both sides = 0,014 mm total both sides.
a
No minimum means that there are no established minimum check limits.
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ISO 15211:2022(E)
Table 7 (continued)
Minimum check limit
Coating mass
Triple-spot test Single-spot test
designation
2 2
g/m g/m
Z100 100 85
Z180 180 150
Z200 200 170
Z275 275 235
Z350 350 300
Z450 450 385
Z600 600 510
Z700 700 585
NOTE 1 Because of the many variables and changing conditions that are characteristic of continuous zinc coating, the
coating mass is not always evenly divided between the two surfaces of a zinc-coated sheet; neither is the coating evenly
distributed from edge to edge. However, it can normally be expected that not less than 40 % of the single spot check limit
will be found on either surface.
NOTE 2 The coating thickness can be estimated from the coating mass using the following relationship:
2
100 g/m total both sides = 0,014 mm total both sides.
a
No minimum means that there are no established minimum check limits.
5.5.2 Coating adherence
The zinc-coated twin-roll cast steel sheet shall be capable of being bent in any direction, in accordance
with the mandrel diameter requirements of Tables 8 and 9, without flaking of the coating on the outside
of the bend. Flaking of the coating within 7 mm from the edge of the test piece shall not be cause for
rejection.
Table 8 — Coating adherence for structural quality steel sheet
180° bend-mandrel diameter
e ≤ 2 mm
Base-metal
Coating mass designation
grade designation
Up to Z450
Z700
Z350 Z600
HR 275 1a 2a 3a
HR 340 1a 2a 3a
HR 380 2a 2a 3a
...
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 15211
ISO/TC 17/SC 12
Steel sheet, twin-roll cast, zinc-coated
Secretariat: JISC
by the continuous hot-dip process, of
Voting begins on:
2021-11-09 structural quality and high strength
Voting terminates on:
2022-01-04
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 15211:2021(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 2021
---------------------- Page: 1 ----------------------
ISO/FDIS 15211:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
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 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/FDIS 15211:2021(E)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Dimensions .2
5 Conditions of manufacture .2
5.1 Steelmaking . 2
5.2 Chemical composition . 2
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 . 6
5.5.1 Coating mass . 6
5.5.2 Coating adherence. 7
5.6 Weldability . 8
5.7 Painting . 8
5.8 Surface treatment . 8
5.8.1 Mill passivation . 8
5.8.2 Mill phosphating . 8
5.8.3 Oiling . 8
5.9 Coated coil joining . 9
5.10 Dimensional and shape tolerances . 9
6 Sampling . 9
6.1 Tensile test . 9
6.2 Coating tests . 9
6.2.1 Coating mass . 9
6.2.2 Triple-spot test . 9
6.2.3 Single-spot test . 9
6.2.4 Coating adherence. 9
7 Test methods .10
7.1 Tensile test . 10
7.2 Coating properties. 10
7.2.1 Coating mass . 10
7.2.2 Coating adherence. 10
8 Designation system .10
8.1 General . 10
8.2 Coating type . 10
8.3 Coating mass . 10
8.4 Coating finish condition . 11
8.5 Surface treatment . 11
8.6 Base-metal grade . 11
8.7 Examples . 11
9 Retests .12
9.1 Machining and flaws . .12
9.2 Elongation .12
9.3 Additional tests . 12
10 Resubmission.12
11 Workmanship .12
12 Inspection and acceptance .12
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ISO/FDIS 15211:2021(E)
13 Coil Size .13
14 Marking . .13
15 Information supplied by the purchaser .13
Annex A (normative) Orders requiring base-metal thickness .15
Bibliography .16
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ISO/FDIS 15211:2021(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 second edition cancels and replaces the first edition (ISO 15211:2012), which has been technically
revised.
The main changes are as follows:
— Clause 3 update.
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 2021 – All rights reserved
---------------------- Page: 5 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 15211:2021(E)
Steel sheet, twin-roll cast, zinc-coated by the continuous
hot-dip process, of structural quality and high strength
1 Scope
This document specifies the requirements for steel sheet, in coils and cut length, metallic-coated by the
continuous hot-dip zinc-coated twin-roll cast process, of structural and high strength quality.
The product is intended for applications requiring corrosion resistance, and paintability.
The steel sheet is produced in a number of grades, coating masses, surface treatments and ordering
conditions.
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
continuous hot-dip 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
3.2
normal spangle
finish obtained 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 S (normal spangle with skin pass) or N (normal spangle, no skin pass), however,
it can be variable in appearance and not suitable for decorative paintings.
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ISO/FDIS 15211:2021(E)
3.3
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.
3.4
differential coating
coating deliberately produced to have a different coating mass on each surface
3.5
skin pass
light cold rolling of the product
Note 1 to entry: The purpose of skin passing is one or more of the following: to minimize the appearance of coil
breaks, stretcher strains and fluting; to control the shape or to obtain the required surface finish.
Note 2 to entry: Some increase in hardness and some loss in ductility will result from skin passing.
3.6
twin-roll cast steel sheet
steel sheet produced by casting to near final thickness directly from the liquid metal with minimal hot
rolling to achieve the final thickness
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 zinc on both surfaces of the sheet, expressed in grams per square meter (g/m ) of sheet
4 Dimensions
Zinc-coated structural and high strength quality twin-roll cast steel sheet is produced in thicknesses
up to 2,0 mm, inclusive, after zinc coating, and in widths up to 2 000 mm in coils and cut lengths. Zinc-
coated twin-roll cast steel sheet less than 600 mm wide, slit from wide sheet, is considered as sheet.
The thickness of zinc-coated twin-roll cast steel sheet may be specified as a combination of the base-
metal and metallic coating or base-metal alone. The purchaser shall indicate on the order which method
of specifying thickness is required. If the purchaser does not indicate any preference, the thickness as
a combination of the base-metal and coating shall be provided. Annex A describes the requirements for
specifying the thickness as 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 steel sheet are left to the discretion of the manufacturer. Upon 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, 2 and 3.
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ISO/FDIS 15211:2021(E)
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, 2 and 3. 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, 2
and 3 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 3 and 4.
Table 1 — Chemical composition (heat analysis) for structural quality steel sheet
Mass fractions in percent
Base-metal
C Mn P S
a
Si
grade designa-
max. max. max. max.
tion
HR275
HR340
HR380
0,25 1,35 0,040 0,035 –
HR410
HR480
HR550
a
“–” indicates that there is no requirement, but the analysis shall be reported.
Table 2 — Chemical composition (heat analysis) for high strength steel sheet
Mass fractions in percent
a d d d a
Base-metal C Mn P S Si V Ti Nb N
Class
grade desig- max. max. max. max. min. min. min.
nation
b
1 0,22 1,35 0,04 0,04 – 0,008 0,008 0,008 –
HSS 310
2 0,15 1,35 0,04 0,04 – 0,008 0,008 0,008 –
b
1 0,23 1,35 0,04 0,04 – 0,008 0,008 0,008 –
HSS 340
2 0,15 1,35 0,04 0,04 – 0,008 0,008 0,008 –
b
1 0.25 1,35 0,04 0,04 – 0,008 0,00 0,008 –
HSS 380
2 0,15 1,35 0,04 0,04 – 0,008 0,008 0,008 –
1 0,26 1,50 0,04 0,04 – 0,008 0,008 0,008 –
HSS 410
2 0,15 1,50 0,04 0,04 – 0,008 0,008 0,008 –
a
“–” indicates that there is no requirement, but the analysis shall be reported.
b
For each reduction of 0,01 % below the specified carbon maximum, an increase of 0,06 % manganese above the
specified maximum shall be permitted up to a maximum of 1,50 %.
c
The purchaser has the option of restricting the nitrogen content. It should be noted that, depending on the microalloying
scheme (for example use of vanadium) of the producer, nitrogen is permitted as a deliberate addition. Consideration should
be given to the use of nitrogen-binding elements (for example vanadium and titanium).
d
The producer shall add at least one or more of the elements V, Ti or Nb.
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ISO/FDIS 15211:2021(E)
Table 2 (continued)
a d d d a
Base-metal C Mn P S Si V Ti Nb N
Class
grade desig- max. max. max. max. min. min. min.
nation
c
1 0,26 1,50 0,04 0,04 – 0,008 0,008 0,008 –
HSS 450
c
2 0,15 1,50 0,04 0,04 – 0,008 0,008 0,008 –
c
1 0,26 1,65 0,04 0,04 – 0,008 0,008 0,008 –
HSS 480
c
2 0,15 1,65 0,04 0,04 – 0,008 0,008 0,008 –
c
1 0,26 1,65 0,04 0,04 – 0,008 0,008 0,008 –
HSS 550
c
2 0,15 1,65 0,04 0,04 – 0,008 0,008 0,008 –
a
“–” indicates that there is no requirement, but the analysis shall be reported.
b
For each reduction of 0,01 % below the specified carbon maximum, an increase of 0,06 % manganese above the
specified maximum shall be permitted up to a maximum of 1,50 %.
c
The purchaser has the option of restricting the nitrogen content. It should be noted that, depending on the microalloying
scheme (for example use of vanadium) of the producer, nitrogen is permitted as a deliberate addition. Consideration should
be given to the use of nitrogen-binding elements (for example vanadium and titanium).
d
The producer shall add at least one or more of the elements V, Ti or Nb.
Table 3 — Limits on additional chemical elements for structural quality steel sheet
Mass fractions in percent
Cu Ni Cr Mo Nb V Ti
Element
max. max. max. max. max. max. max.
Heat analysis 0,50 0,30 0,30 0,15 0,008 0,008 0,008
Product analysis 0,53 0,33 0,34 0,16 0,018 0,018 0,018
Table 4 — Product analysis tolerances
Mass fractions in percent
Element Maximum of specified element Tolerance over the maximum speci-
fied
C 0,26 0,04
Mn 1,65 0,05
P 0,04 0,01
S 0,04 0,01
NOTE The above maximum tolerance is the allowable excess over the requirements of the heat analysis specified in
Tables 1 and 2.
5.4 Mechanical properties
The mechanical properties for structural quality steel sheet and high strength steel sheet shall be as
shown in Tables 5 and 6.
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ISO/FDIS 15211:2021(E)
Table 5 — Mechanical properties for structural quality steel sheet
b
A
a
R R
min.
eL m
Base-metal grade
min. min.
%
designation
MPa MPa e ≤ 2 mm
L = 50 mm L = 80 mm
o o
HR275 275 380 15 14
HR340 340 340 9 8
HR380 380 380 8 7
HR410 410 410 7 6
HR480 480 480 6 5
HR550 550 550 5 4
Key
R : lower yield strength
eL
R : tensile strength
m
A: percentage elongation after fracture
L : gauge length on original test piece
o
e: thickness of steel sheet, in millimetre(s)
2
NOTE 1 MPa = 1 N/mm
a
The yield strength may be measured either by 0,5 % elongation proof stress, R (proof strength under load) or by
t0,5
0,2 % offset, R , where a definite yield strength phenomenon is not present.
p0,2
b
Use either L = 50 mm or L = 80 mm to measure elongation. For materials up to and including 0,6 mm in thickness, the
o o
elongation values in this table shall be reduced by 2.
Table 6 — Mechanical properties for high strength steel sheet
b
A
a
R R
min.
eL m
Base-metal
grade desig- Class min. min.
%
nation
MPa MPa e ≤ 2 mm
L = 50 mm L = 80 mm
o o
1 310 410 18 17
HSS 310
2 310 380 18 17
1 340 450 15 14
HSS 340
2 340 410 15 14
Key
R : lower yield strength
eL
R : tensile strength
m
A: percentage elongation after fracture
L : gauge length on original test piece
o
e: thickness of steel sheet, in millimetre(s)
2
NOTE 1 MPa = 1 N/mm
a
The yield strength may be measured either by 0,5 % elongation proof stress, R (proof strength under load) or by
t0,5
0,2 % offset, R , where a definite yield strength phenomenon is not present.
p0,2
b
For thicknesses up to 2 mm, use either L = 50 mm or L = 80 mm. In cases of dispute, however, only the results obtained
o o
on a 50 mm test piece shall be valid.
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ISO/FDIS 15211:2021(E)
Table 6 (continued)
b
A
a
R R
min.
eL m
Base-metal
grade desig- Class min. min.
%
nation
MPa MPa e ≤ 2 mm
L = 50 mm L = 80 mm
o o
1 380 480 13 12
HSS 380
2 380 450 13 12
1 410 520 11 10
HSS 410
2 410 480 11 10
1 450 550 10 9
HSS 450
2 450 520 10 9
1 480 585 8 7
HSS 480
2 480 550 8 7
1 550 565 7 6
HSS 550
2 550 620 7 6
Key
R : lower yield strength
eL
R : tensile strength
m
A: percentage elongation after fracture
L : gauge length on original test piece
o
e: thickness of steel sheet, in millimetre(s)
2
NOTE 1 MPa = 1 N/mm
a
The yield strength may be measured either by 0,5 % elongation proof stress, R (proof strength under load) or by
t0,5
0,2 % offset, R , where a definite yield strength phenomenon is not present.
p0,2
b
For thicknesses up to 2 mm, use either L = 50 mm or L = 80 mm. In cases of dispute, however, only the results obtained
o o
on a 50 mm test piece shall be valid.
5.5 Coating
5.5.1 Coating mass
The coating mass shall conform to the limits for the coating designations shown in Table 7. The
interested parties shall agree upon the coating mass of differentially coated products. If a maximum
coating mass is required, the manufacturer shall be notified at the time of ordering.
Table 7 — Coating mass (total both sides)
Minimum check limit
Coating mass
Triple spot test Single spot test
designation
2 2
g/m g/m
a a
Z001 no minimum no minimum
NOTE 1 Because of the many variables and changing conditions that are characteristic of continuous zinc coating, the
coating mass is not always evenly divided between the two surfaces of a zinc-coated sheet; neither is the coating evenly
distributed from edge to edge. However, it can normally be expected that not less than 40 % of the single spot check limit
will be found on either surface.
NOTE 2 The coating thickness can be estimated from the coating mass using the following relationship:
2
100 g/m total both sides = 0,014 mm total both sides.
a
No minimum means that there are no established minimum check limits.
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ISO/FDIS 15211:2021(E)
Table 7 (continued)
Minimum check limit
Coating mass
Triple spot test Single spot test
designation
2 2
g/m g/m
Z100 100 85
Z180 180 150
Z200 200 170
Z275 275 235
Z350 350 300
Z450 450 385
Z600 600 510
Z700 700 585
NOTE 1 Because of the many variables and changing conditions that are characteristic of continuous zinc coating, the
coating mass is not always evenly divided between the two surfaces of a zinc-coated sheet; neither is the coating evenly
distributed from edge to edge. However, it can normally be expected that not less than 40 % of the single spot check limit
will be found on either surface.
NOTE 2 The coating thickness can be estimated from the coating mass using the following relationship:
2
100 g/m total both sides = 0,014 mm total both sides.
a
No minimum means that there are no established minimum check limits.
5.5.2 Coating adherence
The zinc-coated twin-roll cast steel sheet shall be capable of being bent in any direction, in accordance
with t
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