Are you looking for galvanizing and painting methods? Galvanizing and painting methods are globally recognized methods of protecting structural steel.
Knowing the advantages and disadvantages of galvanizing versus painting, as well as the applicability of each system, helps to evaluate the suitability of each type.
The most important corrosion protection component in both zinc galvanizing and cast painting is zinc.
The mass of zinc present is the standard method for evaluating the durability of metal coatings, and all international standards use mass per square meter to define coating durability for a wide range of galvanized products.
The amount of zinc in a zinc-rich coating is not clearly defined and the method of specification is misleading. Zinc-rich paint specifications indicate the weight percentage of zinc in the dry film of the paint coating.
An inorganic zinc-rich paint can contain 78% zinc in the dry film, and a high-quality organic (epoxy) zinc-rich paint can contain more than 90% zinc in the dry film. The volume of zinc in a zinc-rich paint is very small because zinc is about seven times denser than the organic binder.
The mass of zinc per square meter is therefore significantly lower than when galvanizing the same thickness.
Testing carried out by the South Australian Road Authority to test the zinc content of various types of zinc-rich paint revealed the following:
In zinc-rich organic paint – 75 micron solvent-based coating – 185 g/m2 Water-based – 250 g/m2 Zinc-rich organic paint – 75 micron solvent-based coating – 185 g/m2 2 A Comparison between hot dip galvanizing and inorganic zinc die casting paint can be made as follows.
| Characteristics | Hot dip galvanizing | Inorganic zinc paint |
| Application | Factory | field or factor |
| Corrosion protection | Cathodic and barrier coating | barrier |
| Hardness/abrasion resistance | 179 to 250 DPN | Varies depending on type |
| durability | 50 years or more | 12 -15 years |
| Cathodic protection | Zinc metal is anodic | Perhaps; zinc content may be too low for conductivity/bending materials may be non-conductive, minimizing cathodic projection |
| 2,000 hour dive test | No corrosion of the base steel | The paint absorbed water and corrosion of the lower layer of the steel substrate occurred |
| Exposure to ultraviolet radiation | No impact on performance | No serious deterioration |
| Performance Anger Test | -100°C to 350°C | Deterioration at 250°C |
Source: Internet
