FREQUENTLY ASKED QUESTIONS

What is hot dip galvanizing?

Please refer to the Hot Dip Galvanizing section.

 

How does UNIK ensure that the galvanizing meets the industry standard?

UNIK adopts a very comprehensive, strict international standard in its galvanizing process. UNIK follows the standard issued by the British Standards (BS) and the American Society for Testing and Materials (ASTM), hence the coating thickness is according to BS EN ISO 1461:2009 and ASTM A123.

What is the approximate service life of galvanized parts?

The zinc corrosion rate and the duration of protection is determined by the quality of the coating (thickness) and the amount of corrosive elements present in the immediate environment. For example, in a rural environment where vehicle traffic is reduced, the virtual absence of corrosive emissions allows galvanizing to easily last for 100, even 150 years without maintenance.

Conversely, in an industrial/marine environment where the presence of corrosive elements (chlorides, sulfides) is significant, galvanized steel can last 50 to 100 years.

How long does the galvanizing process take?

Galvanizing lead-times can vary depending on the time of year and how much demand there is within the industry, however most orders are completed within one week. The actual process of Hot Dip Galvanizing takes approximately half a day from start to finish so small urgent items are often processed within 24 – 48 hours.

How does the cost of painting compare with galvanizing?

The cost aspect of the coating is usually split into two sections, the initial cost and the maintenance cost. The life cycle cost of a coating combines the total initial cost and all of the maintenance costs together to give the overall coating cost for the duration the steel is in service.

Why must parts be perforated before galvanizing?
The ventilation holes are required when immersing steel for venting air, and drain holes are required to enable the full flow of liquid when cleaning and during galvanization. Since the material must be fully protected, zinc must circulate freely in all cavities of a part or structure.

 

Why does the galvanized coating thickness depend on the steel thickness?

In order to create a perfect galvanized coating, it is necessary that iron and zinc are in proportion in a way that they diffuse into one another and are able to create galvanized coating. So, in cases when more iron is taken to react with zinc, one may end up with a thin coat. It is said that a thicker coating can be developed if the steel pieces are thicker as well. Moreover, steel along with phosphorus and silicon plays a vital role in enabling a galvanizing reaction as the galvanized coating thickness is highly dependent on the overall steel chemistry and its thickness.

What type of materials will not galvanize?

Iron is necessary for a galvanizing reaction to happen, so if you try galvanizing copper or aluminum, they will not develop a galvanized coating. Stainless steel will not develop a galvanized coating either.