Galvanized Steel

Durable
A galvanized coating is one of the most durable forms of corrosion protection on the market. An average coating thickness of 85 microns, the same thickness as a sheet of A4 paper, can protect a steel structure for the better part of 100 years. One of the inherent benefits of hot dip galvanizing is that when clean steel that is greater than 6mm thick is submerged into molten zinc, it will develop a minimum mean coating of 85 microns. This coating thickness will meet the corrosion performance required in many applications across the UK and Ireland today. In inland areas across the UK and Ireland, a galvanized coating can weather at less than one micron per year, giving it incredible longevity. Even in coastal environments an 85 micron coating can still deliver a life expectancy of 30 years or more.

Sustainable
The long-term durability provided by galvanizing is achieved at relatively low environmental burden in terms of energy and other globally relevant impacts. Several studies have demonstrated the high economic and environmental costs associated with the repeated maintenance painting of steel structures. These burdens can be significantly reduced by an initial investment in long-term protection. Lack of attention to optimal corrosion protection can leave a damaging economic legacy of repeated maintenance costs. In social housing projects, future maintenance costs will be borne by the local authorities. In public infrastructure projects, use of galvanized steel leads to lower maintenance budgets, releasing public funds for other purposes.

Cost-effective
The true cost of protecting steel work from corrosion has to take into consideration two important elements, the initial cost of protection and the lifetime cost. Hot dip galvanizing is often perceived to be more expensive than it is. There are two reasons for this: Firstly, that such a high performance coating is automatically assumed to be expensive. Secondly, the initial cost of galvanising relative to paint has changed significantly over recent years. Painting costs have steadily increased whilst galvanising costs have remained stable.

Proven
Galvanizing is all around us, with the galvanising industry recording increased production year on year. From the smallest components to the largest structural elements, galvanized steel proves itself time and time again as trustworthy and reliable. As an industry, UK and Irish galvanizers can point to a history spanning over one hundred and sixty years. Many plants have been in the same family for generations, protecting built assets for decades. It is an industry built upon track record and proven performance, which is rigorously tested through expert monitoring and performance data collection.

Reliable
There are a number of reasons why galvanising steel is the most reliable form of corrosion protection. Firstly, as a natural metallurgical reaction – a function of introducing clean steel into molten zinc at a specified temperature – galvanizing is a replicable process. Unlike a paint coating, the metallurgical bond that is formed through galvanizing becomes part of the steel itself and is not merely a chemical or mechanical bond. As a natural reaction, galvanizing occurs automatically and does not rely on manual application, or require cooling and reapplication of additional layers. The resultant galvanised coating protects steel from day one and can be depended upon for generations. We have embarked on creating an archive of case histories. This will feature a broad range of projects, locations and encompass details from coating thickness measurements to coating aesthetics.

Honest
Corrosion protection that works from day one. If your galvanized coating is there you can be sure it is working. With hot dip galvanizing seeing is indeed believing. Due to the metallurgical bond that is formed when steel is dipped into molten zinc, a galvanized coating offers straightforward, secure protection from the get-go. Hot dip galvanizing requires rust-free, uncontaminated steel for the process to occur. Once the coating is present, it is impossible for it to fail from underneath. Other coatings can adhere to residual contaminants, this can undermine performance, lead to flaking and cause premature failure. If you can see a continuous galvanized coating on day one, you can be confident of long term protection.
Over a matter of months or years, the initial bright, silvery finish will change to form a duller patina as the surface reacts with oxygen, water and carbon dioxide. A complex but tough, stable, protective layer is formed which is tightly adherent to the zinc.

Predictable
Batch hot dip galvanizing is a standardized process which produces a quantifiable coating thickness. The coating is simply specified through British, European and international standards. The coating thickness depends upon the gauge of the steel that is galvanized and is produced consistently across the component, both inside and out. This can be measured easily throughout its lifetime, using non-destructive methods. Galvanizing weathers in a predictable, linear fashion. This guarantees that if climactic conditions are stable, the lifespan of a galvanized coating can be correctly forecast, and there will be no unexpected surprises.
The lifespan of the coating is also exceptionally long compared with other forms of corrosion protection and will weather at less than one micron per year in certain climates. The local rate of weathering of any given galvanized coating can be reliably calculated.

Offers Complete Coverage
There are multiple reasons why hot dip galvanizing outperforms other organic coatings. A crucial factor is the way the process achieves complete coverage of a component, both inside and out. After an initial cleaning cycle, clean iron or steel components are immersed into molten zinc, commonly at around 450°C. The rate of reaction is rapid and a typical time for immersion is only a few minutes. Heavier articles with a high thermal inertia may take longer. The dipping of steel into a tank of molten zinc via the hot dip galvanizing process means the zinc can access even the trickiest areas. A further benefit of hot dip galvanizing is that hollow components are coated on internal surfaces too, meaning that a structure will not corrode from the inside out. In addition, the coating will also build up at vital corners and edges, unlike brushed or sprayed coatings, which traditionally thin out in these areas. Hot dip galvanizing is used equally for small components, making sure they are given the same level of corrosion protection as larger articles. Complete structures receive complete corrosion protection.

Tough
Due to its unique metallurgical bond, a galvanized coating is incredibly tough, offering exceptional performance across multiple layers. An initial outer layer provides reliability as a buffer zone, helping to absorb any initial shock to the coating. Underlying zinc-iron alloys can be harder than mild steel itself, and will further reduce any potential penetration of the coating or the exposure of bare steel. This means that a galvanized coating is highly chip resistant and particularly suited to areas of high frequency industrial wear. A galvanized coating can also help prevent damage during construction, where its toughness can protect components during transport, erection and the other mechanical activities.

Offers Three Way Protection
A Physical Barrier:A galvanized coating provides a physical barrier which is metallurgically bonded, and prevents the underlying steel from being exposed to atmospheric conditions. This coating is highly durable and has an adhesive strength of up to seven times that of organic paint coatings. It is a robust, physical barrier comprising of a softer, zinc, outer layer which will absorb initial impact loading and underlying layers of strong metallurgically bonded alloys. These alloys are often harder than the original steel they protect and offer excellent abrasion and chip resistance. As a protective barrier, a galvanized coating weathers at a slow rate and can easily provide corrosion protection for over 60 years, maintenance free.
Sacrificial Protection: A galvanized coating will corrode preferentially and slowly. Small scratches on a galvanized surface will not normally require any repair work, and if small areas do become exposed to humidity and other corrosive elements, the galvanized coating will corrode preferentially and at a slower rate than the underlying steel. This type of protection is called cathodic protection and means the coating will sacrifice itself before it allows the steel to be compromised. It is a key function of the long-term protection offered by hot dip galvanizing.
Prevention of sideways creep: In the unusual event that a galvanized coating is locally compromised and bare steel is exposed, the zinc coating will limit damage and prevent a form of corrosion known as sideways creep. Sideways creep can severely undermine paint coatings and is caused as rust deposits accumulate on bare steel and spread underneath and across the paint film. Left untreated, sideways creep will produce peeling and the eventual breakdown of the paint coating. Hot dip galvanizing prevents this kind of deterioration.