« Back to Swedish version  |  »News  |  »Zinc and the Environment
»10 good reasons for hot dip galvanizing | »  Comparative Properties
10 GOOD REASONS FOR HOT DIP GALVANIZING
1. COMPETITIVE FIRST COST
For most applications the cost of galvanizing is lower than that of applying alternative coatings. Furthermore galvanizing has been getting steadily cheaper compared with painting.

The reason is simple: alternatives - particularly painting- are very labour intensive compared with galvanizing which is highly mechanized, closely controlled factory process.
2. LOWEST LIFETIME COST
Low initial cost and long life make galvanizing the most versatile and economic way of protecting steel for long periods.


There are bonuses from no maintaince or extended maintenance intervals; fewer problems of access in remote areas, diffi- cult terrain or when buildings are closely packed together; also when there are safety restrictions e.g. electricity pylons.

3. LONG LIFE
Well documented years of experience have proved the benefits of hot dip galvanized protection. At least 20 - 40 years are commonplace in industrial and marine environments, 50 - 100 years in less aggresive atmospheres.
4. THREE-WAY PROTECTION
Galvanized coatings protect steel in three ways. Firstly, the coating weathers at a very slow rate giving a long and predictable life. Secondly, the coating corrodes preferentially to provide cathodic protection (sacrificial) to any small areas of steel exposed through drilling, cutting or accidental damage; scratches are sealed by weathering pro- ducts from the zinc. Thirdly, if the damage area are one day. larger, the sacrificial protection prevents the sideways creep of rust which can undermine paint coatings.
5. SPEED AT APPLICATION
A full protection coating can be applied in A 4-coat paint system requires a week
6. EASE OF INSPECTION
Galvanized steel simplifies inspection ot the protective finish. The nature of the process is such that if the coating looks continuous and sound, it is so. Thicknesses (weights) - simply specified through EN-ISO 1461 or regular, predictable and simply specified. Galva-national standards - can be easily checked with a magnetic probe or other simple non- destructive testing gauge.
7. RELIABILITY
The process is relatively simple, straightforward and closely controlled. The thicknesses of coatings formed nizing is one of the coatings which is completely defi- ned by DS/ISO 1461, NS 1978, SFS 2765 or SS 3583.
8. FASTER CONSTRUCTION
Galvanized steel is ready for use. No further site surface preparation, painting, touch up or inspection necessary. Once erected the galvanized steel is ready for use: and cladding can begin immediately, thus accelerating the construction programme.
9. COATING TOUGHNESS
Galvanizing is unique: the hot dip process produces a coating which is bonded metall- urgically to the steel. No other coating pro- cess has this feature and as a result galva- nized steel has by far the greatest resistance to mechanical damage during handling, storage, transport and erection - an important factor where steelwork is to be shipped across the world.

Furthermore the toughness of this protection makes it particurly suitable for use in situations where abrasion could be a problem.
10. COMPLETE COVERAGE
Because it is formed by dipping steel in molten zinc all parts of the surface of the steel are coated - inside, outside, awkward corners and narrow gaps which would be impossible to protect in any other way.

In addition the coating builds up at vital corners and edges - rather than thinning out as do brushed, sprayed and other dipped coatings..
« Back

Senast uppdaterad 2004-05-18 14:52