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Quality requirements

Contact
GALV-EST AS
Kuusalu vald 74604
Kiiu Harjumaa
Phone +372 60 35 770
galv-est@galv-est.ee

Customer service:
Phone +372 603 5773
GSM +372 53 33 0093

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Design characteristics

DESIGNERS AND PRODUCERS HAVE TO KNOW THE PECULIARITIES OF THE PRODUCTS TO BE HOT-DIP GALVANIZED AND CONSULT WITH AS GALV-EST EXPERTS WHEN NEEDED.

DIMENSIONS OF THE PRODUCTS:
The dimensions of the product to be hot-dip galvanized depend on the dimensions of the treatment baths and zinc baths used, and the Galv-Est plant gives the following recommended dimensions for the product or structure: 1,500 mm (width) x 2,700 mm (height) x 13,500 mm (length) and a max weight of 12 tonnes. Galvanizing of longer products is possible but in that case the plant has to be consulted extensively, and a double dipping of the product has to be considered necessary, which is not always permitted and includes additional costs.

COMPOSITE STRUCTURES:
The best results are gained with a product that has been designed in such a way that the mass and axes of the geometric symmetry of the connected components coincide, since materials expand during the heating process and an uneven linear expansion may cause the product to warp. The use of materials of different thickness in the compound structures should also be avoided. If, for instance, intermittent welding is used to combine a massive profile that heats up slowly to a light profile material, then the latter one, which heats up faster, will warp due to linear expansion, which is usually permanent. Similarly, also, U-beams will warp during hot-dip galvanizing due to the faster heating of the sides of the box, but such deformations are relatively easily rectified.

It is also important that products made out on thin metal sheets are strengthened against deformation. In this case, better results are achieved with strengthening through bending; the use of profile steel support fins should be avoided.

HOLLOW STRUCTURES:
Examples for determining the locations of ventilation openings:

When using hot-dip galvanizing it is important to know that the use of closed off profiles is very dangerous, since the closed in air usually causes the item to break open when it expands. It is also important that hollow products have openings for the draining of the liquid zinc in order to prevent waste and to keep the weight of the product from increasing too much. Without these openings galvanizing is not possible. Therefore products are designed with ventilation and drainage openings, which are based, above all, on the position in which the product is lowered into the bath.


If the design allows for it then the drainage openings should be as big as possible. For each hollow structure, there has to be an opening in the highest and lowest part of the structure when being dipped; see the following illustration:


Nõrgumis- ja tuulutusavade suuruse tabel erinevat tüüpi õõnsussektsioonidele – soovitatud miinimumid.
Toru läbimõõt
mm
Toru pikkus ja avade läbimõõt - mm
3m 6m 9m 12m
20 10 otsad lahti otsad lahti otsad lahti
30 12 otsad lahti otsad lahti otsad lahti
40 14 20 otsad lahti otsad lahti
60 16 24 32 otsad lahti
80 20 30 40 50
100 25 40 50 60
120 30 50 või 2 x 30 60 või 2 x 40 70 või 2 x 50
160 40 60 või 2 x 40 80 või 2 x 50 90 või 2 x 60
200 50 80 või 4 x 30 100 või 4 x 40 120 või 4 x 50
250 60 100 või 4 x 40 120 või 4 x 50 140 või 4 x 60
300 75 120 või 4 x 50 150 või 4 x 60 160 või 4 x 70

CONTAINERS, VESSELS:
The required sizes of the drainage openings depend on the volume of the container, as follows:
Volume
litres
of one drainage opening
Ø mm
two drainage openings
Ø mm
Ventilation opening
Ø mm
500 80 25
1000 115 2x80 40
1500 140 2x100 45
2000 160 2x115 55
2500 175 2x125 60
3000 200 2x140 70
3500 225 2x150 75
4000 225 2x160 80
4500 240 2x170 85
5000 250 2x175 90
5500 265 2x185 95
6000 280 2x200 100
7000 300 2x220 110
8000 325 2x225 115
9000 350 2x240 120
10000 350 2x250 125
Containers that have their inner surface hot-dip galvanized have to have openings that allow for the fast inflow, outflow, and complete emptying of the liquid zinc (for a closed reservoir of one square-metre there has to be an opening with a diameter of at least 40 mm).