Galvanizing - processes and costs in comparison
Galvanizing is a form of surface refinement that protects steel particularly well against corrosion. Ordinary coatings such as paints or powder coatings, protect the component by preventing a reaction with oxygen (oxidation). However, if the protective layer is damaged, corrosion quickly occurs at the damaged area.
In galvanizing, on the other hand, the protective layer consists of a thin layer of zinc which, in addition to protection against oxygen, also has a decisive property. The zinc of the coating is less noble than the underlying steel construction. The zinc layer therefore acts as a so-called sacrificial anode. This ensures that the surrounding steel structure is protected against corrosion until the zinc layer is used up.
As a result, the steel structures are protected against corrosion even in the case of defects such as scratches, cuts, holes or edges. For larger imperfections you should still rework to avoid corrosion. Furthermore, consideration should be given to corrosion protection during subsequent processing, and this should be taken into account in the installation situation and in the choice of connecting elements.
Further details on the professional galvanizing and handling of galvanized steel structures can be found in the standards attached at the end of the text.
Method for galvanizing steel structures
In hot dip galvanizing, the steel structure or components are immersed in a bath of liquid zinc. The temperature of the zinc is about 450 ° C. The zinc layer thicknesses are between 50 and 150 micrometers. In continuous strip galvanizing systems, such as those used for galvanizing steel sheets or pipes, significantly lower zinc layer thicknesses are also produced.
Cost of hot dip galvanizing
Depending on the order volume, size and complexity of the components or steel structures, the Prices for hot dip galvanizing at approx. 0,20 € / kg, suitable Suppliers for hot dip galvanizing from Central and Eastern Europe you will find in our directory.
In galvanic galvanizing the components are not immersed in a molten zinc, but in an electrolyte bath. The steel structure or the components serve as a cathode during galvanic galvanizing. The anode is an electrode made of pure zinc. By applying a voltage, a zinc layer is deposited on the steel structure. The thickness of this zinc layer can be controlled by the duration of the process. However, the zinc layer does not become uniformly thick everywhere. As a rule, this achieves layer thicknesses between 5 and 40 micrometers, which is significantly less than with hot-dip galvanizing. Corrosion protection by galvanizing is therefore generally worse than with hot-dip galvanizing, but the process also offers advantages:
Due to the small thickness of the zinc layer, the dimensional accuracy of the components is better than with hot dip galvanizing. Thread in about need not be reworked during galvanic galvanizing. Furthermore, it can also be used for temperature-sensitive workpieces. To further improve the corrosion protection, the components can still be chromated or powder coated.
Cost of Galvanizing
The Cost of Galvanizing are much higher than when hot-dip galvanizing and start at around 1 € / kg, suitable Suppliers for Galvanizing see our business directory.
Zinc wire is melted during spray galvanizing and applied to the workpiece by means of compressed air, as in painting. The layer thicknesses are similar to those of hot dip galvanizing and lie between 80 and 150 micrometer. The spray galvanizing can also be applied to components that are not suitable for hot dip galvanizing.
Decisive disadvantages are that it can not be used in cavities and that the workload is comparatively high. Furthermore, the components must be further coated or painted after spray galvanizing. The labor costs are therefore a decisive factor in spray galvanizing, which is why it offers To find suppliers for spray galvanizing in the CEE area.
Zinklammellenbeschichtung - The Zinklammellenbeschichtung offers itself for Scharauben and small parts in larger quantities.
Mechanical Galvanizing - Mechanical galvanizing is used on springs and fasteners.
Diffusion galvanizing, also called sheradizing - Diffusion galvanizing is used for components with high temperature resistance.
Find suppliers for galvanizing
Our IATF 16949 certified Partner company in Hungary offers different services in the field of galvanizing and other surface treatments:
- Galvanizing steel
- Nickel plating of copper
- Chemical nickel plating (7-9% P) of steel
- Copper plating of steel
- Silvering of steel, copper or brass
- Tinning of copper
- KTL coating of steel or zinc
- ZnNi zinc nickel coating
Find suppliers of galvanized steel structures
As a rule, the manufacturing companies for steel construction undertake the order processing with the respective galvanizing plant. You can use our agency service without much effort Find suppliers of galvanized steel structures.
Galvanizing for craft or laboratory applications
Build electroplating machines yourself
There are for the craft supplies and for small parts such as jewelry DIY kits for galvanizing * for home. These are usually used for silvering or gilding, with the appropriate electrolytes * and a suitable one Zinc anode * But they are also suitable for galvanizing. In addition to plating baths, there are also simpler Handgalvanisiergeräte *.
Zinc dust or liquid zinc
Zinc dust color and Liquid zinc * are simple ways to retroactively apply a cathodic corrosion protection. It is a primer that contains fine zinc particles. This zinc dust provides the corrosion-inhibiting properties. They are both pranks and practical Zinc sprays *.
Further literature on galvanizing steel:
DIN EN ISO 1461 - Zinc coatings applied by means of hot-dip galvanizing (hot-dip galvanizing) - Requirements
and Examination - and accompanying sheet 1
DIN EN ISO 14713 - Protection of iron and steel structures from corrosion - Zinc and aluminum coatings -
DIN EN 2063 - Thermal spraying - Metallic and other inorganic coatings - Zinc, aluminum and their alloys (ISO 2063: 2005)
* the marked links serve advertising purposes
Sources: Wikipedia, the above standards