Hot dip galvanising of steel is one of the most efficient and well documented methods of surface treatment.
The steel product to be hot dip galvanised and rust protected is submerged in a bath of molten zinc holding a temperature of approx. 455 degrees C. In the contact area between the steel and the zinc a reaction occurs by which an iron/zinc alloy is established. This means that the zinc layer cannot scale off nor can rust be formed under it. Further more, due to the self-curing effect of the zinc layer, minor damages are remedied, after some time anodically dissolved zinc covers the damaged spot.
The process is carried out by skilled operatives to ensure that our high quality standards are maintained. Weland products are as standard supplied hot dip galvanised in accordance with class SS-EN ISO 1461. We are certified in accordance with ISO 9001.
Zinken Weland AB
In the contact area between the steel and the zinc a reaction occurs by which a layer of iron/zinc alloy is established. The thickness of this layer depends on the grade of steel employed (thicker layer on killed steel).
Hot dip galvanising by the wet process
Zinken Weland i Göteborg applies the wet process which means that the goods are brought directly from the pickling bath to the zinc bath. The fluxing agent applied on top forms a cover on the zinc bath and thus acts on the goods when they are being submerged. Zinken Weland can galvanise goods up to 12 metres length.
Mått betkar: 1500 x 1800 x 12500 mm
Mått zinkkar: 1500 x 2100 x 11000 mm
Hot dip galvanising by the dry process
Zinken Weland i Ulricehamn applies the so-called dry process, which means the goods are submerged in a fluxing bath and then dried before being submerged in the zinc bath. Goods up to 6 metres length can be galvanised.
Dimensions pickling bath: 1300 x 2500 x 6200 mm
Dimensions zinc bath: 1300 x 2500 x 6200 mm
Thickness of layer on sharp corners
The zinc layer assumes the same thickness or even more on sharp corners as on plane surfaces.
If the surface is damaged
The steel in the damaged area is protected against corrosion by the remote action of the zinc. After some time anodically dissolved zinc covers the damaged spot. The protection remains as long as there is zinc around the damage.
Inside tubes and cavities
Tubes and goods with closed spaces have to be vented. This enables the air to escape and the zinc to enter the cavity. Thus the goods are protected both on the inside and the outside.
Zinc Coat – Length of Life
The diagram shows middle-age for different thicknesses of zinc penetration in different environments.