WHAT IS HOT DIPPED GALVANIZING?

The hot dip galvanizing process creates a combination of corrosion protection properties which are unmatched by other coating systems.

The thick metallic zinc envelope completely covers the surface of the steel creating a series of metallurgically bonded zinc-iron layers. The tightly adherent middle alloy layers are, in fact, harder than steel core, providing a high level of resistance to mechanical damage in addition to corrosion protection.

Since zinc corrodes preferentially providing cathodic protection to areas of bare steel, the structure remains protected even in the event of exposure due to abrasion or impact damage. The sacrificial nature of zinc prevents the exposed steel from corroding, eliminating any undercutting or blistering of the coating.

A hot dip galvanized zinc coating has the capacity to provide maintenance-free protection performance for the designed lifespan of the structure. It has a rate of corrosion proportional to its thickness and directly determined by the environment to which it is exposed - typical lifespan expectations based on an 87 micron thick galvanized coating, for example, range from twenty years in a heavy industrial environment to more than fifty years in a rural one.

Galvanized Coatings are thicker at corners and edges. The process is "self-inspecting." Any coating problems or inadequacies will be immediately apparent when the steel is withdrawn from the molten zinc. Unlike multicoat paint systems, this allows for immediate corrective action.

1. LOWEST FIRST COST- In many cases galvanizing now costs less to apply than coating with much shorter lives.

2. LOWEST LONG TERM COST- Even in cases where the initial cost of galvanizing is higher than a comparable alternative, galvanizing is almost invariably cheapest in the long term.

3. THE ECONOMIC CASE FOR GALVANIZING IS STILL IMPROVING- There is a high labour cost component inherent in the application of most other coatings and their cost directly reflects increases in the cost of labour.

4. LONG LIFE- The standard 2 oz. ft.² galvanized coating has a typical life without maintenance of more than 50 years in rural environments, and 20 to 25 years in urban and coastal conditions.

5. RELIABILITY- The galvanized coating is bonded metallurgically to the base steel so that it becomes part of the steel surface it protects. Coating life and performance are reliable and predictable.

6. COATING TOUGHNESS- A galvanized coating has a unique metallurgical structure which gives outstanding resistance.

7. ELIMINATION OF MAINTENANCE FOR LONG PERIODS- The use of galvanizing defers maintenance for long periods compared to other coatings for steel. Remember, hidden maintenance costs can be extremely expensive when they entail difficult access, or plant shut-down, and when structures are located in remote areas.

8. AUTOMATIC PROTECTION FOR DAMAGED AREAS- Galvanized coatings corrode preferentially to steel, providing sacrificial or cathodic protection to small areas of steel exposed through damage to the coating. Unlike organic coatings no touch up is needed when damage occurs.

9. COMPLETE PROTECTION- Every part of a galvanized article is fully protected, even recesses, sharp corners and inaccessible areas. No coating applied to a structure or fabrication after completion can provide the same protection.

10. EASE OF INSPECTION- Galvanized coating thickness is controlled automatically by steel thickness and a standard, minimum coating mass results. Soundness and continuity are judged readily by the eye.

11. MECHANICAL PROPERTIES- Galvanizing has no effect on the mechanical properties of commonly galvanized structural steel.