Conventional hot-dip galvanising provides steel with lasting protection against rust and is therefore always a very good choice when it comes to effective corrosion protection.
In the molten bath, liquid zinc heated to 450°C bonds inseparably with the steel. The solid zinc coating completely covers the workpiece. Even all surfaces in hollow parts are fully protected.
Thanks to the metallurgical reaction between zinc and steel (FeZn alloy), hot-dip galvanising provides lasting and effective protection against underlying rust and, with its cathodic protection, is even able to seal minor damage.
This means that the metallic appearance of the steel is preserved, as is its surface structure. When freshly applied, the zinc coating is generally clear. Depending on the material used, it may be slightly more shiny or matt and may or may not have the typical zinc bloom.
Over time, corrosion of the zinc forms a patina and its appearance becomes darker and more matt. The patina is a weather-resistant protective layer composed of zinc oxide and zinc carbonate.
Depending on the thickness of the zinc layer, hot-dip galvanising can provide protection for varying lengths of time. The piece galvanising process carried out by ELEO stands out because its zinc coating is thicker than mass-produced galvanised coatings. This gives you more effective protection against corrosion, which can last for decades without any maintenance costs.
Process steps
At ELEO, hot-dip galvanising is only carried out in professional galvanising workshops that are ISO-certified and strictly comply with DIN standards.
After delivery to the galvanising workshop, parts showing traces of grease or oil are cleaned in a degreasing bath. Aqueous-alkaline or acidic degreasing agents are usually used. After an alkaline degreasing bath, the parts are quickly immersed in a water bath to ensure that no degreasing agents remain on the parts to be galvanised.
Next, a pickling treatment is used to remove impurities such as rust or scale from the surface of the steel. Pickling is usually carried out using diluted hydrochloric acid.
After pickling, the parts are rinsed twice in a flux bath and then dried. The components are then coated by immersion in a galvanising bath, which has a zinc content of at least 98.5%, in accordance with DIN EN ISO 1461. The part to be galvanised remains in the bath until it reaches its temperature. Once the steel components have been removed from the galvanising bath, they are cooled and then finished in accordance with standards. These finishes are also referred to as plastering or deburring, during which the zinc spikes are removed.
Uses and benefits
Hot-dip galvanisation integrated into the treatment process offers the best protection against rust compared to other galvanisation processes. This is why ELEO chooses to use only this method of galvanisation, which offers the following advantages:
- excellent cathodic protection against corrosion, even in hollow elements and corners, making maintenance almost unnecessary
- high mechanical strength
- a good ecological balance, an environmentally friendly process
