Standards

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The basic specifications for zinc coating is determined by a single standard – BDS EN ISO 1461 “Hot dip galvanizing on iron and steel products – Specifications and test methods”. When the details or constructions are made of one type of steel, the obtained zinc coating is of the same thickness. The coating thickness depends on both the composition and the thickness of the steel.

Minimum coating thickness of non-centrifuged samples:

Product and its thickness	Local coating thickness (minimum) μm		Average coating thickness (minimum) μm
Product and its thickness	g/m²	µм	g/m²	µм
Steel > 6 мм	505	70	610	85
Steel > 3 мм < 6 мм	395	55	505	70
Steel > 1,5 мм < 3 мм	325	45	395	55
Steel < 1,5 мм	250	35	325	45
Cast iron> 6 мм	505	70	575	80
Cast iron< 6 мм	430	60	505	70

For ease of calculation: The relative weight of zinc is 7.133 g/cm³ (at 200 ° C) assuming it is 7.2 g/cm³. To obtain a layer of 1 μm over 1 sq. m., 7.2 grams of zinc are needed.

Zinc coatings are primarily used as protective coatings, not as a decorative element! They must meet the technical requirements of BDS EN ISO 1461:

The coating must be uniform, continuous and have good adhesion to the parent metal. No cracks, blisters, residues of zinc slag, flux or sharp zinc protrusions (growths) are allowed;
No drops, drains, thickenings, hard zinc beads, gripping recesses are allowed on the working surface.
Depending on the roughness and composition of the parent metal, the coating may have a silver-glossy to matte dark gray color. The surface of the coating may be smooth and/or rough;
The stains which appear if the galvanized products are stored in damp environment (white rust), worsen the appearance but do not reduce the durability of the coating;
It is allowed to have non-galvanized area of 1% of the total galvanized surface, but not more than 10 cm², and respectively less than 0.05% and 10 cm² (according to BDS EN ISO 1461);
Defected areas must be repaired by applying a layer of lacquer-dye materials with a high zinc content of not less than 90 μm;
The average thickness of the coating is 60 μ to 80 μm.