Steel corrosion protection demands the all-round approach. During the process of steel hot reducing a thin layer of oxides is being formed on the surface that attaches to the main metal at once. When weathering, the further corrosion attacks the layer. In the end, from well-attached blue compound this layer transforms into a yellow one of baseline adhesiveness. This is exactly the reason why it is essential to remove the oxide layer in order to provide longstanding surface coating protection.
Steel structures corrosion protection
In today’s construction they more often use different metal structures. These are structures of galvanized, stainless steel and other metals. And oftentimes there rises a natural question: “If it is necessary to paint galvanized steel structures?”.
The answer is simple – indeed, this surface needs to be painted. There are at least to reasons for painting such structures:
- galvanized steel is still exposed to corrosion (even if much less than the ordinary one);
- unpainted metal often doesn’t fit into the object architectural or engineering solution.
Thus the first aim of galvanized steel painting is the structure additional corrosion protection. The second objective of steel protective paint is giving the decorative or so-called finished appearance to the structure. Having the complex composition that prevents material structure mutation, corrosion protective paints also allow to increase the treated surface working life. Steel protective paint provides protection from:
- liquid chemical compounds penetration;
- direct sunlight;
- gravel, sand, dust mechanical action;
- salts, acids, alkalis impact.
Painting the steel
Before starting painting the structure of galvanized steel it is necessary to pick the corrosion protective coating. Before galvanized steel painting it is essential to estimate following factors:
- surface preparation: spot blasting, mechanical or manual cleaning;
- spot where coating application is expected;
- environmental conditions and used application methods.
It is essential to pick the anticorrosive primer carefully, because it provides the foundation for the whole system of protection. The primer is applied directly to steel, so it should be adaptable to the method of surface preparation. Also it should be the main anticorrosive mechanism, also adaptable to the surface coating (in this case – galvanized steel).
For exposed to average corrosive loads steel structure painting it is recommended to apply the acrylic paint for galvanized metal. This coating doesn’t need the surface preparatory padding, it is applied in one layer and allows to perform painting at negative temperatures.