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Galvanising

PRODUCTS FOR THE HOT DIP GALVANIZER Cleaners/degreasers

New Dimension ND 7 Supreme is used for removing oils, greases and general shop soils before acid pickling. Due to its low alkalinity it can be used where no rinse is available before the acid pickle. If a suitable tank is not available it is possible to replace the first acid in a line with New Dimension ND 7 Supreme solution to provide a first stage degreaser. This has been done at several customers and although this reduces pickling capacity, the overall pickling time has been reduced as clean work pickles better and faster than greasy work. Most applications run at temperatures of 30-350 C but as cleaning performance increases with temperature, the hotter the better. The cleaner is supplied as a water based liquid concentrate to be diluted on site. New Dimension ND 7 Supreme can also be used as a spot cleaner to replace thinners or solvent when discrete areas need extra attention.

If heavy duty cleaning is required, for instance when weld anti-spatter or heavy sticky oils have to be removed, Masco 245 DM is the choice. This is a very aggressive cleaner good at removing difficult soils. It will also penetrate into any rust, oxide or scale present, removing the oils and starting to break down the scale and oxides. This gives the pickle a head start, improving both the speed and the quality of the pickling. Masco 245 DM comes with an extra detergent pack to boost Add Cleaner 501 Dip to boost its grease removing power. Some customers using Masco 245 DM have also reported lower ash levels, presumably due to the increased grease and oil removal especially on the inside of tubular work.

Acid Additives

Although a separate degreaser is best practice, if space is at a premium and no room can be found for a degreasing bath, then we can supply an acid stable degreasing additive called Add Cleaner 530 Dip to go into the pickle. Acid cannot penetrate through grease deposits and therefore cannot pickle the surface properly. Add Cleaner 530 Dip lifts the grease and wets the work, allowing the pickle to get to the steel surface and pickle effectively. Removing the grease at the pickle stage also helps prevent grease and oils carrying over, preventing proper fluxing, increasing ash levels and blinding filter bags.

Inhibitors in acids do more than protect the work. Using an effective inhibitor such as Cangalv Inhibitor No1in the acid pickle will protect the work during long pickle times, reduce acid consumption and extend the life of the acid. It will also prolong the life of jigs, chains, catch nets and other equipment used in the acid.
Cangalv Inhibitor No 1 is stable at high iron and zinc content, when some inhibitors can come out of solution and leave the galvanizer without protection. This splitting of the inhibitor can often be seen as a dark oily layer floating on the acid bath.
Cangalv Inhibitor No 1 is compatible with the Add Cleaner 530 Dip, making it possible to combine inhibition and oil removal in the one pickle tank.

Post galvanizing treatment

Traditionally chromate has been used to passivate galvanized coatings to prevent white corrosion. Hexavalent chromium is now classified as a class 1 carcinogen so an alternative such as our Hydroclear is very welcome. Hydroclear is a water-based treatment, free of any heavy metals, applied to the freshly galvanized products by simple dip or spray. After air drying it will protect the bright finish of the coating during storage and use. The Hydroclear coating will also act as a primer for paint finishes such as powder coating, replacing expensive and time-consuming pre-treatments such as phosphating or T-washing. Hydroclear is used extensively by galvanizers in Europe and many prestige projects have benefited from the Hydroclear treatment.

An example of this is the Schalke football stadium in Germany where 55,000 seats were galvanized and Hydroclear coated and still remain bright after two years in use.
Applying the Hydroclear directly after galvanizing minimises any extra handling of the work making it cost effective and economical.