GALVANIZED STEEL SPECIFICATIONS

General Description
Hot-dip galvanized sheet is produced on continuous zinc coating lines from either cold rolled (thickness range 0.25 to ≤2.0mm) or
hot rolled (thickness range 2.01 to 3.0mm) steel substrate, in coil form. It is produced to the equivalent requirement of EN 10346,
EN10143, ASTM A653M, ASTM A924, SABS 3575 or SABS 4998 as well as ArcelorMittal South Africa`s ISQ standards.
The galvanizing process yields homogeneously zinc-coating sheet with a bright, smooth metallic finish. The zinc coating can be
supplied with a normal or flattened minimized spangle finish.

Zinc coatings of different thickness may be ordered to suit specific end-use requirement. The thickness and type of steel substrate
are selected on the grounds of mechanical and structural considerations. For tolerance on galvanized sheet refer to the data sheet:
Galvanized Material Tolerance (File reference C1.2).

Mechanical Properties
Refer to Table 1: Mechanical properties specifications of substrate.

Coating Mass
The prefix Z in the coating designation indicates a pure zinc coating and the number denotes the total mass of the coating on both
sides of the sheet (g / m²). The coating mass (Refer to ISO 1460) is given in Table 2.

Table 2 Coating mass

Coating Minimum Requirement Minimum Requirement Nominal thickness of

designation Triple Spot Test (g/m²) Single Spot Test (g/m²) Zinc coating per side
Total Both Sides Total Both Sides (um)
Z1001 100 85 7
Z1502 150 128 10
Z200 200 170 14
Z275 275 235 19
Z450 3,4 450 385 32
Z600 3,4 600 510 43

Notes:
1. Only available on 0.27 and 0.30mm ISQ 550 material.
2. ISQ specification only.
3. Not recommended for forming grades.
4. Not available on full hard material.

Bend Test
Bend test to evaluate the adhesion of the zinc coating are carried out in accordance with the relevant specifications. In addition to
this, impact adherence cupping test are performed on all products, irrespective of specification, to ensure good adhesion of the zinc
coating.

The coating bend test specimens are suitable for bending through 180º in any direction without showing any signs of flaking. An
area of 6mm from each edge of the specimens is disregarded in order to exclude the effect of the cut edge. The inside diameter of
the coating bend test is prescribed in Table 3.
Table 3 Minimum inside bend diameter

Coating Commercial & Forming Steel Structural Steel

designation ISQ 230, LFQ (Lock-Forming Quality) and DQ (Drawing ISQ 300
Quality)

0.4 ≤ t ≤ 2.0 t﹥2.0 0.4 ≤ t ≤ 1.2

Z150 / Z200 / Z275
0t 2t 2t
Z450 / Z600
2t 2t 2t
Notes:
1. Given as a multiple of t (Coated material thickness)
2. ISQ 550 does not have specified requirements for this property.

Dimensions
Table 4a Available dimensions (Regular spangle)

Thickness ˡ (mm) Width (mm) 3,4

0.25² 762, 914
0.27²
0.30²
0.40 925 ≤ w ≤ 1 219
0.47 925 ≤ w ≤ 1 320
0.50
0.53
0.58 925 ≤ w ≤ 1 524
0.80
1.00
1.20
1.40
1.60
1.90 925 ≤ w ≤ 1 225
2.40
3.00

Note:
1. Coated thickness, i.e. including the thickness of the zinc coating.
2. Available as ISQ 550 coils only.
3. The following standards widths are available (Depending upon thickness): 762, 914, 925, 940, 1000, and 1175, 1219, 1225,
1250 and 1320 mm.
4. Structural grades that require medium to high strength mechanical properties are subjects to thickness and width limitations
(Limitations available on enquiry).
5. Maximum width for Full Hard (ISQ 550 3T) material is 1225mm.

Table 4b: Available Dimensions (Flattened Minimized Spangle)

Un- Passivated Passivated Width (mm)

Thickness (mm)²
Width(mm) Excluding LFQ material
0.40 – 0.41 925 ≤ w ≤ 1219 925 ≤ w ≤ 1050
0.42 – 0.44 925 ≤ w ≤ 1225 925 ≤ w ≤ 1075
0.45 – 0.49 925 ≤ w ≤ 1265 925 ≤ w ≤ 1115
0.50 – 0.59 925 ≤ w ≤ 1320 925 ≤ w ≤ 1175
0.60 – 1.20 N/A 925 ≤ w ≤ 1225
Hot Rolled Substrate
Due to the nature of the hot rolling process, surface blemishes such as surface scratches and coil breaks which may be highlighted
by the zinc coating, can occur on material with a thickness of greater than 2.01mm. Neither of these defects will affect the
functionality of the material however they may not be aesthetically acceptable. The end-user should take cognizance of this, as no
claims for aesthetic reasons can be entertained.

Zinc Coating Surface Finish

The following surface finishes may be ordered to suit specific end-use requirements:

1. Normal or Regular Spangle

This finish is obtained during normal solidification of a hot-dip zinc coating on steel sheet, and results in the formation of a coating
which exhibits either no spangle or zinc crystals of different sizes and brightness depending on the galvanizing process and
conditions.

If the end user require a heavier coating (Z450 or Z600), there is a distinct tendency for the coating to develop very visible sag lines
and ripples that results in a rough surface.
However, the solidified zinc appearance has no effect on either the quality or corrosion resistance of the coating.
Normal or Regular spangle is supplied for a wide range of applications where over-painting for maintenance purposes may be
undertaken at a later stage.

2. Flattened Minimized Spangle

This zinc coating finish is obtained by restricting the normal zinc crystal growth followed by the application of a skin pass process.
The zinc coating thus obtained has improved formability and the zinc surface serves as an excellent base for pre-painting, post –
painting and powder coating applications.

This finish is recommended for applications where a high gloss paint finish is required. It is available for zinc coating of mass up to
Z275, and a maximum material thickness of 1.20 mm if passivation is required, or a maximum thickness of 1.60 mm if passivation
is not required.

Stain Ageing
Galvanized steel sheet tends to stain age and this may lead to the following:

1. Surface markings from stretcher stain (Lüderʼs lines) or fluting when the sheet is formed.
2. Deterioration in ductility.

It is recommended that the period between final processing at the mill and fabrication be kept as short as possible, preferable not
exceeding six weeks.

Fretting
Fretting, also known as either friction marks or friction stain can occur superficially on hot dip galvanized coils.
It is caused by the interaction of two surfaces in contact with one another, which are simultaneously subjected to either high or low
frequency vibration. For this reason, fretting, if encountered, may be present when material is transported in trucks over relatively
long distance.

The fretting is observed as black patches which are a superficial phenomenon only, and that they are confined to usually only a few
microns on the material surface. The life expectancy of the material is thus not compromised by the presence of fretting. It may be
of aesthetic concern to some end-users, but form a functional point of view the material may be applied accordingly.
Zinc Surface Treatment
The following surface treatments are used by ArcelorMittal South Africa to reduce the possibility of wet storage stain (sometimes
referred to as ʻwhite rustʼ) during transport and storage:

1. Passivation
Passivation by chromic acid (ideally even coating of 20 to 40 mg/m² total on both sides) is normally applied to all galvanized
material. In cases where this treatment may interfere with subsequent processing such as phosphating, the galvanized steel may
be ordered without passivation, in which case oiling is recommended. Although every endeavour is undertaken to ensure that the
passivation coatings are evenly applied, occasionally local color variations are encountered. However, these color differences will
not impair the quality of the zinc coating and with time they will gradually disappear

2. Oiling
The corrosion preventive oil is used to coat galvanized sheet as an additional protection against wet storage staining during
handling and storage. Oil is only applied if requested.

3. Unoiled and Unpassivated

If an unoiled and unpassivated galvanized steel sheet is ordered, the danger of wet storage stain is increased and therefore no rust
complaints will be entertained. Proper protective packing should be specified to protect the material against the ingress of moisture
during transport and storage, although this would not guarantee us storage stain free material. Various packaging options are
available (see ʻPackaging Specificationʼ).

Wet Storage Corrosion

When galvanized sheet in coil or cut lengths is stored under wet conditions, the galvanized surface may be damaged by wet
storage corrosion.
Unless the galvanized material is stored in a warehouse under a controlled atmosphere, no “white rust” complaints will be
entertained. Packs of galvanized material must not stacked directly on floors.

Rainwater or water vapour can easily be drawn in between tightly stacked profiled or flat sheets, or between laps of coils by
capillary action. Due to the absence of freely circulating air, this moisture cannot evaporate, causing unfavorable conditions that
may result in wet storage corrosion of galvanized sheeting.

Normally light white staining on galvanized sheet is not reason for concern. The wet storage corrosion process will stop when the
affected areas are dried and exposed to the atmosphere. The discoloration will disappear within a few months during the normal
weathering of the material. Where affected surfaces will form part of unexposed overlaps or other concealed areas that may be
subject to extended periods of dampness, such areas should be cleaned and additionally protected.

Corrosion Protection
Under normal exposed conditions the zinc coating is gradually consumed through atmospheric corrosion and therefore, the heavier
the coating, the longer the period of protection.

It is recommended that galvanized sheeting be over-painted preferably before the first appearance of red corrosion products.

Expected Corrosion – Free life (in years)

Coating Weight Rural Industrial Marine 1 Marine 2

(g/m²) (yrs) (yrs) (yrs) (yrs)
Z 100 7 – 10 3–5 0.5 – 1.5 1 – 3.5
Z 150 10 – 15 5–9 0.5 – 2 1.5 – 5
Z 200 13 – 20 7 – 10 1–2 2–7
Z 275 15 – 25 10 – 20 1–3 3 – 10
Z 450 25 – 40 16 – 28 2–5 5 – 16
Z 600 40 – 60 21 – 30 3–7 7 – 20

Marine 1 Refers to a distance between 0, 5 and 3, 0 km from the sea.

Marine 2 Refers to a distance between 3, 0 and 20, 0 km from the sea.

These values are only indicative because the exposure period until the first signs of Red Rust corrosion can vary considerably
depending upon the conditions of the site.
Cut Edge Corrosion Resistance
The zinc coating cut edges of sheet against corrosion by cathodic action, as the adjacent zinc coating will oxidize protecting the
uncoated edge. Material with a gauge less than 2.5 mm is adequately protected along the cut edge by a Z275 zinc coating.

Welding
Zinc coating steels may be welded satisfactorily by most commonly practiced welding techniques. However, closer control of
welding parameters is necessary in order to reduce the formation of toxic fumes that are not encountered when welding uncoated
steel.

Painting
Chemical conversion coating and primers have been developed to provide good adhesion of subsequent paint films on zinc-coating
surfaces. To obtain optimum results it is essential to adhere to the instructions of the paint manufacturers.

Warranty
ArcelorMittal South Africa guarantees the prime quality of the product, but cannot accept liability for scratches or other damage to
the material sustained during and after profiling, transport to or storage at the building site, and during erection.

Quality Assurance
A quality assurance system that complies with SANS 9001 is in operation throughout the manufacturing process, and ArcelorMittal
South Africa`s products conform to the requirements of both SABS ISO 3575 and SABS ISO 4998.

Supply conditions
Hot-dip galvanized sheet is supplied in term of Price List 140 and ArcelorMittal South Africa`s General Conditions of Sale.
Table1. Mechanical properties specifications of the steel substrate

Commercial Steels
Forming Drawing
Roofing/ General Full hard / SAE / AISI ¹ Structural Steels 3,4
Steels² Steels²
Structural Purpose (HRB ≥ 85 )
Higher
Moderate Moderate
average
roll forming Severe drawing,
Moderate Moderate strength
and bending, severe
Moderate bending, forming for Mechanical or structural properties of the base metal are specified or
bending lock-forming bending,
Application Bending and roll forming and roll and roll moderate required
with ample and roll lock-forming
forming forming forming forming
bend forming and roll
and
radius forming
bending

LFQ
ASTM A653 Structural Steel (SS) 2001
ISQ 230
SAE / AISI ASTM DQ
ASTM A653M- SAE / AISI
ISQ 550 1006 A653M- `01
Specification `01 Commercial 1012 Gr 340
ISQ 300 (1995) Forming Gr 230 Gr 255 Gr 275 Gr 5507
Steel (CS) Type (1995) Class 1
Steel (FS)
A
Type A

YS t≤0.60 t≥0.61
(MPa)min 230 255 275 340
Mechanical 550 550
UTS 275 300 310 360 380 450
properties5 570 570
(MPa)min 20 18 16 12
El(%)min 16 16
En 10346
JIS G3302 En 10346 EN 10346 EN 10346 EN 10346 EN 10346 EN 10346
DX51D
SGCC DX52D S220GD S250GD S280GD S350GD S550GD
(2009)
Similar (2009) (2009) (2009) (2009) (2009) (2009)
SANS
Specifications 6 SABS ISO SANS SANS SANS SANS SANS SANS
3575:1996
3575:1996 3575:1996 4998:1996 4998:1996 4998:1996 4998:1996 4998:1996
02 Lock-
01Commercial 03 Drawing GR220 GR250 GR280 GR350 GR550
forming

Notes:
1. Chemical analysis only
2. Thickness range 0.40 to 2.00mm with a maximum zinc coating mass of Z275.
3. Thickness greater than 2.00 mm are available on enquiry only.
4. Restricted to certain width to thickness ratios.
5. YS = Yield strengths; TS = Tensile strengths; El = Elongation
6. For details refer to relevant specification.
7. A tensile test is required only if the hardness is below 85 Rockwell B.