Surface treatment

Hot dip galvanizing is one of the most effective methods to protect from corrosion. The method results in an almost maintenance free product during the whole lifetime. Already in 1741, the French chemist Melouin discovered that zinc can protect steel against corrosion. However, it took until 1837 before the method started to be used. It was the engineer Sorel that patented a method to use ammonium chloride as flux. 

Why does Eurostair® use hot dip galvanizing?

Our products are used both outdoors and indoors. Products outdoors are in different degrees exposed to weather and affected by the climate, but products need to be protected even in indoor environments. Especially within industries it is usually demanding environments. Eurostair®’s products should always have the highest quality, have a well-thought out construction and give more value, including for our environment. Hot dip galvanizing is the method that gives our products the highest protection against corrosion with a low environmental impact. 

Method for hot dip galvanizing

Before the material is about to hot dip galvanize it is carefully cleaned from fat, oil, rust, and other filths. This is done by chemical baths that cleans the steel. Further on the material is washed before it is immersed in a pot of hot zinc with a temperature of around 460 °C. This method gives a strong metallic bond between the steel and the zinc which ensures sustainability and creates a cathodic protection. If there would be any micro areas not covered by zinc the cathodic protection will fill this area by itself. As a method the hot dip galvanization created a durable and resistant surface with a long lifespan and is essentially maintenance free. 

Description of the process

The process for hot dip galvanization is carefully controlled. First a degreasing and pickling takes place to erase all fat areas, contaminations and welding residues. Further on the material is carefully washed. After the material is dried it is immersed into the zinc bath. Since zinc has an open structure it can bind with the steel surface. In this moment, a joining on a molecular level takes place which gives the strong and effective protection. After cooling the material is inspected and controlled to ensure the desired result.

For more information about hot dip galvanization and meticulous description about the process we recommend Nordic Galvanizers site. 

Duplex treatment is recommended mainly for painted products outdoors. Hence, duplex treatment can also be needed if the product should be placed indoors in a humid or corrosive environment. Duplex treatment, i.e. both hot dip galvanization and powder coating, gives a very good corrosive protection since the underlying zinc prevents from corrosion even if the paint layer is damaged, for example in transportation or assembly. A duplex treatment gives a surface treatment with a low lifetime cost. The method is slightly expensive initially but on the other hand the maintenance and replacement costs are substantially lower. Powder coat the staircase in optional RAL-color. 

Why does Eurostair® use powder coating? 

We use duplex treatment on a painted staircase that should be placed outdoors or if a painted staircase should be placed indoors in a corrosive environment. Eurostair®’s duplex treatment means that we perform surface treatment in two steps, first a hot dip galvanization followed by powder coating. Hot dip galvanization gives the product a long lifespan and effectively protects against corrosion. The powder coating is an environmentally effective painting method with highest quality for both indoor and outdoor use. For us at Eurostair® a duplex treatment is the obvious choice for a painted product which should have the highest protection against corrosion. 

Methods for duplex treatment 

In our duplex treatment we merge two effective surface treatments. Hot dip galvanizing is one of the most effective methods for corrosion protection available. Hot dip galvanization according to the norm EN 1461 is completely maintenance free during the whole lifespan. Zinc is a basic metal compared to steel and therefore minor damages in the zinc coating will be cathodically protected and therefore does not need to be repaired. Outside of this corrosion protection we then applicate powder coating. Powder coating is done with polyester powder with a layer thickness of approximately 60 my. There are not any limitations when it comes to colors. Today we can paint with the whole RAL-scale but also NCS-S if you prefer. It is important to state the gloss when you chose color. Eurostair® recommend gloss between 80-30 where 80 in blanc and 30 is matt. 

Description of the process

It is essential that the pretreatment and the hot dip galvanization is performed according to the right process. To adhesion and sustainability should work the pretreatment is completely crucial. When the hot dip galvanization has gone through the first step and dried the material is ready to be powder coated with polyester powder. The powder is applicated on the material by electrostatic or friction charge and afterwards the powder is hardening in an oven at minimum 180 ºC. During the process ventilation air from the powder application is cleaned in effective purifications. The powder that misses the material is taken care of in a recycling system and reversed to the spray gun.