All metal structures used in construction must have reliable protection against various environmental factors, and first of all, against corrosion. What materials are used for this? Find out further.
General information
Corrosion is a physical and chemical process in which metal interacts with the environment. During this reaction, the properties of the material change. As a result of such processes, it begins to break down.
Anti-corrosion protective coatings
They are used to process items to prevent them from being destroyed. Anti-corrosion coating, presented in the form of special enamels or paints, has a number of advantages in comparison with other materials with similar properties. Among the main advantages of such products should be noted:
- Ability to process large structures and elements of complex configuration.
- Ease of application.
- Economical, recoverable during operation.
- Relatively affordable cost compared to othersmaterials.
- Ability to get a different color coating.
Most common formulations
Anti-corrosion coating of metal structures for many manufacturing companies is the main activity. Various materials are used to process structures and elements. Among them are:
- Paint "Stainless steel". This enamel can be used on both clean and rusty surfaces.
- Paint "Nerzhaluks". This composition has high adhesion. This paint is used for decorative and protective treatment of surfaces made of lead, duralumin, aluminum, brass, titanium, copper and zinc.
- Aquametallic paint - water-based acrylic composition.
- Quick Thrower is a fast drying paint.
- Urethane enamel "Polymeron". This compound is highly wear resistant.
- Paint "Cycrol". It is used in the processing of roof structures, galvanized elements.
- Composition "Silver". This anti-corrosion metal coating is silver white in color.
- Decorative enamel "Nerzhaplast". It is liquid plastic.
- "Moloteks" - is hammer paint.
- "Nezjamet-aerosol" - available in cans.
- "Phosphosoil" - used for non-ferrous and ferrous metals.
- "Phosphomet" - is a phosphating modifier,rust converter.
How is anti-corrosion coating of pipelines carried out? For processing such elements are used:
- "Nerzhakhim". This anti-corrosion pipeline coating is a chemically resistant vinyl primer-enamel.
- "Polyurethol" is a polyurethane oil- and petrol-resistant mixture.
- "Epostat" - epoxy chemically resistant anti-corrosion coating of pipes (ground-enamel).
- Zinconol is a polyurethane zinc rich primer.
Urizol mix
With the help of this composition, an anti-corrosion coating of pipes transporting petroleum products, oil itself and natural gas is carried out. Fittings, crane assemblies, connecting parts are processed with this mixture. The composition is used to protect against atmospheric and underground corrosion of pipelines of pumping, compressor, pumping gas distribution stations, head facilities, oil depots, integrated treatment plants and raw material storage facilities, as well as other similar structures, the operating temperature of which is up to 60 degrees. The Urizol mixture is also used to insulate piles and other concrete elements.
Features of the composition
First of all, it should be noted the ease and simplicity of applying the mixture. For processing, as a rule, a sprayer is used. From the moment the components are combined, a reaction begins, during which polyurea is formed. Further, the system passes from liquid to non-fluid gel-like, andafter and into the solid state. If the polymerization speed is not high enough, smudges will form. They, in turn, prevent the necessary increase in the thickness of the coating. At the same time, stickiness will remain for a long period. It prevents the implementation of control intermediate measurements of the thickness and uniformity of the layer. If the polymerization rate is too high, the adhesion of the composition to the surface is reduced. In this case, the thickness of the insulation is uneven. The spray gun during operation in this case quickly becomes clogged. To prevent such situations, it is necessary to carefully select the components of the composition and prepare the mixture in accordance with the instructions.
Some recommendations
All components of the Urizol mixture are supplied in special steel barrels. Storage of material is carried out indoors, in sealed containers. High-quality mixing of the components is carried out using special equipment - a two-component spray installation. It provides precise dosing of ingredients in a 1:1 ratio. At the same time, the required pressure (at least 150 atmospheres) and temperature (60-80 degrees) are maintained. Spraying is carried out in a thin layer. Before application, the components are pre-mixed in containers. To do this, the barrels are rolled and shaken.
Composition Benefits
Coating "Urizol", unlike many other polymer mixtures that contain one or another amount of organic volatile solvents,is a composition that includes one hundred percent of the solid phase. Polyurea does not contain plasticizers that tend to "sweat" over time. This process is accompanied by gradual shrinkage and increased brittleness of the protective film. The mixture does not include tar and coal components, which are often added to reduce the cost of the material, but have a carcinogenic effect on the human body. In addition, the composition does not contain solid fillers that provoke abrasive wear of pumping equipment, nozzles in spray installations and mixing chambers. Due to the high reactivity of the polyurea components have a high level of polymerization without catalysts. The increased reliability of the coating is also due to the relatively low sensitivity to temperature and humidity changes. For example, other polyurethane mixtures of similar action have a higher tendency to form a porous film under the influence of moisture, which, in turn, is always present in the original components of the raw material. However, it should be noted that the reliability of polyurea is ensured only with careful observance of the requirements for the process of preparation of processed structures and elements.
Applying an anti-corrosion coating
The processing process includes several stages. First of all, it should be noted that applying an anti-corrosion coating is a rather difficult job. The final result will depend on the thoroughness of the preparation of the elements andthe quality of the composition used. The greatest difficulty is usually the anti-corrosion coating of the bottom of any structure. Next, consider the main stages of work.
Visual inspection
Before carrying out anti-corrosion coating of metal structures, it is necessary to assess their condition. This is done by experts in the field. In the process of visual inspection, the degree of damage to the surface is determined. Based on the results of the assessment, an estimate is drawn up. During this work, various factors are taken into account. These include, in particular, the temperature regime in which the operation of the structure takes place. As well as the influence of atmospheric phenomena and other aggressive environments, the intended purpose of the elements, the type of material that was used in their manufacture. In accordance with this, one or another anti-corrosion coating of the metal will be selected. Large structures usually require special equipment.
Surface preparation
Before using an anti-corrosion coating, the surface of the structure or element should be cleaned. In the process of preparation, pollution of various origins, old paint are removed. Cleaning of the object can be carried out by hydroabrasive, hydrodynamic, abrasive-jet method. After that, it is necessary to degrease the surface. For this, hydrocarbon solvents are used. Upon completion of this stage, the surface of the structure is inspected again.
Processing
Anti-corrosion coating is used whencertain conditions. Immediately before processing, the composition is prepared in accordance with the technology. As a rule, the procedure is carried out by the airless method. This is due to the greatest efficiency of this method. Anti-corrosion coating is carried out in several layers. At the same time, before applying the next, the previous one must dry to one degree or another (information on this is contained in the instructions for use).
Final stage
After the anti-corrosion coating of the metal is completed, a control inspection of the structure or element is carried out. When evaluating the quality of the work performed, special equipment can also be used. As a result of the inspection, the presence or absence of untreated areas or defects is revealed. The level of adhesion of the composition to the surface, the decorative properties of the coating are also evaluated. In addition, it is important to determine the thickness of the dry film. The optimal value is considered to be 240-300 microns. As mentioned above, such processes are carried out by specialists. Upon completion of processing, the customer accepts the object. In doing so, he also receives all the necessary documentation.
