ISO 8353:2024

International
Standard
ISO 8353
First edition
Steel sheet, zinc-aluminium-
2024-12
magnesium alloy-coated by the
continuous hot-dip process, of
commercial, drawing and structural
qualities
Tôles en acier revêtues à chaud en continu d'alliage zinc-
aluminium-magnésium de qualité commerciale, pour
emboutissage ou destinées à la construction
Reference number
© ISO 2024
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ii
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Dimensions . 3
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 .5
5.4.1 Commercial and drawing quality .5
5.4.2 Structural quality .6
5.5 Coating .7
5.5.1 Coating bath composition.7
5.5.2 Coating type designation and coating bath composition .7
5.5.3 Coating mass .8
5.5.4 Coating adherence.8
5.6 Weldability .9
5.7 Painting .9
5.8 Coating finish condition .9
5.9 Surface treatment .9
5.9.1 Mill passivation .9
5.9.2 Mill phosphating .10
5.9.3 Oiling .10
5.9.4 Thin organic film (or Sealing) .10
5.10 Coated coil joining .10
5.11 Dimensional and shape tolerances .10
6 Sampling . 10
6.1 Tensile test .10
6.2 Coating tests .10
6.2.1 Coating mass .10
6.2.2 Triple-spot test .11
6.2.3 Single-spot test .11
6.2.4 Coating adherence.11
7 Test methods .11
7.1 Tensile tests .11
7.2 Coating properties.11
7.2.1 Coating mass .11
7.2.2 Coating adherence.11
7.2.3 Test methods for coating bath composition .11
7.2.4 Coating corrosion resistance . . . 12
8 Designation system .12
8.1 General . 12
8.2 Coating type . 12
8.3 Coating mass . 12
8.4 Coating finish condition . 12
8.5 Surface treatment . 12
8.6 Base-metal quality . 13
8.7 Examples . 13
9 Retests . 14

iii
9.1 Machining and flaws . .14
9.2 Elongation .14
9.3 Additional tests .14
10 Resubmission. 14
11 Workmanship . 14
12 Inspection and acceptance . 14
13 Coil size .15
14 Marking . .15
15 Information to be supplied by the purchaser .15
Annex A (normative) Orders requiring base-metal thickness for T1 . 17
Annex B (normative) Orders requiring base-metal thickness for T2, T3, T4 and T5 . 19
Annex C (informative) Calculation of the coating density .20
Bibliography .21

iv
Foreword
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flat rolled products.
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v
International Standard ISO 8353:2024(en)
Steel sheet, zinc-aluminium-magnesium alloy-coated by the
continuous hot-dip process, of commercial, drawing and
structural qualities
1 Scope
This document specifies the minimum requirements for steel sheet, in coils and cut lengths, metallic-coated
by the continuous hot-dip process, with zinc-aluminium-magnesium alloy coating.
The product is intended for applications requiring high corrosion resistance, formability and paintability.
The steel sheet is produced in a number of quality designations and grades, coating type, coating mass,
surface treatments and coating finish conditions designed to be compatible with differing application
requirements.
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 9227, Corrosion tests in artificial atmospheres — Salt spray tests
ISO 14993, Corrosion of metals and alloys — Accelerated testing involving cyclic exposure to salt mist, dry and
wet conditions
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 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 https:// www .electropedia .org/
3.1
commercial
base-metal quality intended for general fabricating purposes where steel sheet is used in the flat condition,
or for bending or moderate forming

3.2
drawing
base-metal quality intended for fabricating parts where drawing or severe forming may be involved
3.3
deep drawing
base-metal quality intended for fabricating parts where severe forming or severe drawing may be involved
3.4
deep drawing aluminium killed
base-metal quality intended for fabricating parts where particularly severe drawing or forming may be
involved
3.5
extra-deep drawing stabilized
base-metal quality intended for applications where maximum formability is required by applying interstitial-
free steel (3.7)
3.6
structural
base-metal quality intended for parts needing guaranteed mechanical properties and where simple forming
may be involved
3.7
interstitial-free steel
IF
extra-low-carbon steel in which all interstitial elements are combined with titanium and/or equivalent
elements
Note 1 to entry: Interstitial-free steel is sometimes referred to as stabilized steel.
3.8
breakage allowance
agreed upon level of acceptable die breakage not subject to claim
3.9
differential coating
coating which is deliberately produced to have a different coating mass (3.13) on each surface
3.10
blackening
phenomenon where surface of the coating appears blackened, especially the coating composition containing
magnesium, during storage or in a high temperature and high humidity environments
Note 1 to entry: This phenomenon is related to the formation of magnesium oxide and/or zinc oxide on the surface of
the coating.
3.11
smooth finish
smoothness produced by skin-pass (3.12) the coated material in order to achieve an improved surface
condition as compared with the normal as-coated product
3.12
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.

3.13
coating mass
total amount of coating on both sides of the steel sheet, expressed in grams per square metre
3.14
lot
specified quantity of steel sheet of the same designation rolled to the same thickness and coating condition
4 Dimensions
4.1 Zinc-aluminium-magnesium alloy-coated steel sheet is produced in thicknesses from 0,20 mm to 9 mm
inclusive after coating, and in widths of 600 mm and over in coils and cut lengths. Zinc-aluminium-magnesium
alloy-coated steel sheet less than 600 mm wide, slit from wide steel sheet, is considered as steel sheet.
4.2 The thickness of zinc-aluminium-magnesium 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 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-aluminium-magnesium alloy-coated steel sheet 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 Table 3.
Table 1 — Chemical composition (heat analysis)
Mass fractions in percent
Base-metal quality
C Mn P S Ti
max. max. max. max. max.
Designation Name
01 Commercial 0,15 0,60 0,05 0,035 -
a
02 Drawing 0,10 0,50 0,04 0,035 -
a
03 Deep drawing 0,08 0,45 0,03 0,03 -
a
04 Deep drawing aluminium killed 0,06 0,45 0,03 0,03 -
a
05 Extra-deep drawing stabilized 0,02 0,25 0,02 0,02 0,15
b
b
b
320 Structural 0,25 1,70 0,05 0,035 -
b
a
Interstitial-free steel may be applied.
b
Grades 250 and 280: phosphorus − 0,10 % max.; Grade 350: phosphorus − 0,20 % max.
Table 2 — Limits on additional chemical elements
Mass fractions in percent
a a a,b a,b c c,d c,d
Cu Ni Cr Mo Nb V T
i
Element
max. max. max. max. max. max. max.
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
For interstitial-free steels only, the value of 0,15 % titanium, and 0,10 % maximum for niobium and vanadium are acceptable
to ensure that the carbon and nitrogen are fully stabilized.
d
Heat analysis greater than 0,008 % may be supplied after agreement between the manufacturer and purchaser.
Table 3 — Product analysis tolerances for Table 1
Mass fractions in percent
Element Maximum of specified element Tolerance over maximum specified
≤ 0,02 0,01
C > 0,02,  ≤ 0,15 0,03
> 0,15, ≤ 0,25 0,04
≤ 0,60 0,03
Mn
> 0,60,  ≤ 1,70 0,05
P 0,05 0,01
S 0,035 0,01
NOTE  The above maximum tolerance is the allowable excess over the requirement of heat analysis shown in Table 1.

5.4 Mechanical properties
5.4.1 Commercial and drawing quality
5.4.1.1 Ordering conditions
Zinc-aluminium-magnesium alloy-coated steel sheet of designations 01, 02, 03, 04 and 05 are supplied under
either of the following two ordering conditions.
a) Ordering condition A: steel sheet mechanical properties shall, at the time the steel is made available
for shipment, satisfy the applicable requirements of Table 4, when they are determined on test pieces
obtained in accordance with the requirements in Clause 7. The values specified in Table 4 are applicable
for the periods indicated in Table 5 from the time that the steel is available for shipment.
b) Ordering condition B: steel sheet, ordered to make an identified part, shall be supplied with a
commitment for satisfactory manufacturing performance within an established breakage allowance,
which shall be previously agreed upon by the interested parties. In the agreement, the part name, the
details of fabrication, and special requirements (such as freedom from stretcher strain or fluting) shall
be specified.
In the case of ordering condition B, mechanical properties of the steel sheet may also be agreed upon by the
interested parties and such properties may not necessarily satisfy the requirements of Table 4.
5.4.1.2 Fabrication qualities
Zinc-aluminium-magnesium alloy-coated steel sheet is available in several fabrication qualities as given in
3.1 to 3.6.
5.4.1.3 Interstitial-free steel
Stabilized interstitial-free steel (IF Steel) is applicable to orders for designations 02 03, 04 and 05; provided
that the purchaser is informed of the substitution and that related shipping documents reflect the actual
material shipped.
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