Hot-dip galvanised steel
for purely technical surfaces
Durch Feuerverzinken wird kostengünstig eine zwar langlebige, aber rein technische Oberfläche erzielt, denn der Hauptzweck des Feuerverzinkens ist einzig der Korrosionsschutz. Anforderungen an die Ästhetik der Oberflächen sind nicht definiert. Zur Vermeidung von Reklamationen empfehlen wir daher unbedingt, Metallobjekte, die optischen Ansprüchen genügen müssen, zusätzlich oder alternativ in farbbeschichteter Oberfläche auszuführen.
for hot-dip galvanised objects?
Environmental aspects speak
in favour of hot-dip galvanising
Corrosion protection by the way of hot-dip galvanizing saves recources and is sustainable. In direct comparison with other procedures a big amount of CO2 is saved.
Layer thickness according to ISO standard
White rust on hot-dip galvanised surfaces
White rust is the term for streaky corrosion phenomena on the hot-dip galvanised surface. The white rust has no effect on the weather resistance, but makes the garden object look bad. In order to reduce the development of white rust some companies in the galvanizing industry offer additional protective layers. These are relatively expensive and above all useless if the freshly zinc-galvanized objects are treated and stored appropriately. That is why an additional protective coating is no standard and has to be agreed on and ordered separately.
Formation of white rust
White rust can form if the freshly galvanised objects are stored on the construction site under unfavourable weather conditions or temporary air exclusion and at the same time come into contact with water, especially with condensation water with a low mineral content. Also, lower than dew point and low temperatures promote the formation of white rust. The classic case is: the objects stand in the rain under a protective cover in spring or autumn, waiting to be installed. Then the ugly white rust can form after just a few hours!
Removal of white rust
The white rust can be removed under certain circumstances. The rule is: the quicker the reaction after the formation, the easier the removal. White rust can be removed mechanically by using hard nylon brushes. The treated surfaces have to be rinsed with lots of water. Wire brushes are not suitable, as they leave scratches in the soft zinc coating.
Tender text for GaLaBau, for landscape architects and planners
“Rolled flat steel with corrosion protection by hot-dip galvanizing (piece galvanizing) in accordance with DIN EN ISO 1461: 2009-10. For load-bearing, hot-dip galvanized metal and steel components in the area regulated by building authorities, DASt Guideline 022 “Hot-dip galvanizing of load-bearing steel components” shall also be applied.”
The thickness of the zinc coating does not have to be specified separately, as this is regulated in DIN EN ISO 1461.
For the best possible protection against white rust, we recommend the additional sealing of the hot-dip galvanised surface directly ex works during hot-dip galvanising. This is a separate service outside of DIN EN ISO 1461 and must therefore be arranged additionally. Text suggestion: “With additional protective coating for further protection against white rust after the hot-dip galvanizing process.”