What is the Standard for hot dip galvanized coatings?
AS/NZS 4680:2006
Introduction
Australian Standard AS/NZS 4680:2006 – Hot dip galvanized (zinc) coatings on fabricated ferrous articles is the defining standard for hot dip galvanized coating specifications in Australia. It is closely aligned with the International Standard ISO 1461:1999 – Hot dip galvanized coatings on fabricated ferrous products , in keeping with the Australian Governments policy of aligning all Australian standards with appropriate international standards.
AS/NZS 4680 defines the minimum requirements for coating mass (thickness) for various steel sections, methods of test and repairs to galvanized coatings, as well as containing informative information on design for galvanizing, surface preparation for painting and metallurgical information.
Coating thickness requirements of AS/NZS 4680
The coating thickness on significant surfaces shall be not less than the values given in Table 1 or Table 2. If an article includes a number of different thicknesses of steel, each thickness range shall be regarded as a separate article and the relevant values in Table 1 or 2, as appropriate, shall apply.
Where large articles, e.g. structural steel fabrications, are tested by the magnetic method, the local coating thickness shall be the average of 10 determinations performed randomly over an area of 20 cm2 (the reference area). The average thickness shall be the mean of the values taken from three separate test areas (i.e. the mean of 30 determinations).
Unless otherwise specified. thickness measurements shall be carried out at positions not less than 10 mm away from edges, flame cut surfaces and corners.
TABLE 1 -
requirements for coating thickness and mass for articles that are not centrifuged
Article
thickness
mm |
Local coating
thickness
minimum
µm |
Average coating
thickness
minimum
µm |
Average coating
mass
minimum
g/m2 |
51.5 |
35 |
45 |
320 |
>1.5 <3 |
45 |
55 |
390 |
>3 <6 |
55 |
70 |
500 |
>6 |
70 |
85 |
600 |
NOTE:
1 g/m2 coating mass = 0.14 pm coating thickness.
TABLE 2
REQUIREMENTS FOR COATING THICKNESS AND MASS FOR ARTICLES THAT ARE CENTRIFUGED
Thickness of articles
(all components
including castings)
mm |
Local coating
thickness
minimum
µm |
Average coating
thickness
minimum
pm |
Average
coating mass
minimum
g/m2 |
<8
>8 |
25
40 |
35
55 |
250
390 |
NOTES:
1. For requirements for threaded fasteners refer to AS 1214
2. 1 g/m2 coating mass = 0.14 µm coating thickness.
Back to FAQ index
|
