TECHNOLOGICAL REGULATIONS FOR DYING
METAL STRUCTURES FOR LIGHTING MAST SUPPORTS

1. GENERAL PROVISIONS

1.1. The technological regulations apply to work on anti-corrosion protection by painting metal structures of lighting mast supports.

1.2. Technological process for painting metal structures installation site includes the following sequential operations:

Surface preparation - degreasing, cleaning from oxides and scale, removing dust;

Restoration of primer layers applied at the manufacturer and damaged during transportation and installation work;

Application of coating layers of paint and varnish materials - preparation of working compositions of paint and varnish materials, application of the required TECHNOLOGICAL REGULATIONS number of layers of required thickness;

Quality control and acceptance of complex coverage.

1.3. For the technological process, standard and unified tools and equipment must be used.

1.4. To protect metal structures from corrosion at the above-mentioned facility, the following coating system is used.

Coating system

Primer paint and varnish material - “Halopolim-02” 100 - 120 microns

(applied at the factory)

Coating paint and varnish material "Vinikor-62" 80 - 90 microns

Complex coating thickness 180 - 210 microns

1.5. The color scheme of the coating layers of the outer surfaces of metal structures is adopted in accordance with the color scheme.

2. PREPARATION OF THE SURFACE FOR PAINTING

2.1. Before staining metal surface there should be no scale, oxides, damaged primer, organic contaminants (oil, grease), burrs, sharp edges, flux residues, welding spatter.

Surface degreasing

2.3. The degreasing process involves removing fat and oil contaminants under the influence of organic solvents and alkaline degreasing solutions.

2.4. The quality of surface degreasing is checked after the surface has completely dried using one of the methods recommended by GOST 9.402-80. Degreasing degree should be 1.

Mechanical methods for removing poorly applied paint and varnish and preparing welded and bolted assembly joints.

2.5. The degree of cleaning of the surface prepared for applying the primer layer is regulated by GOST 9.402-80: when viewed with the naked eye, scale and other non-metallic layers are not detected. The optimal roughness of a metal surface prepared for painting is Rz30.

2.6. Compressed air intended for painting by pneumatic spraying must comply with the requirements of GOST 9.010-80: moisture and mineral oils in the form of droplets are not allowed.

The presence of water and mineral oil determined by a stream of air directed at the surface of the mirror for 3 minutes or at filter paper (with circles drawn with an ink pencil) for 15 minutes. Drops of moisture and oil are not allowed on the surface of the mirror. Oil stains should not appear on the surface of the paper and the drawn circles should not darken.

2.7. If flux residues, alkali slag, splashes and contact liquid are not completely removed (ultrasonic flaw detection) in the area of ​​welded seams, accelerated destruction of the coating is possible, so you should pay attention to Special attention to prepare the surface in the area of ​​welds and not to allow the use of oils as a coupling liquid when carrying out ultrasonic flaw detection.

Surface preparation quality control

2.8. Monitoring the condition of the surface of metal structures should be carried out no later than 6 hours after surface preparation, and additionally immediately before painting for a period exceeding the permissible duration of the break between the preparation operation and painting.

2.9. The surface prepared for painting must be dry, dust-free, and free from contamination with oils and greases (if any, degrease again).

3. COATING TECHNOLOGY

3.1. Before painting metal structures, incoming inspection of paint and varnish materials should be carried out for compliance with the requirements regulatory documents for these materials in accordance with clause.

3.2. Before starting each work shift, you should check:

Conditions environment(air temperature, relative humidity);

Dew point temperature;

Absence of moisture and oil contamination on the surface prepared for applying paints and varnishes.

3.3. Before applying topcoat paints and varnishes, it is necessary mandatory check the quality of the primer layers applied at the manufacturer. In this case, defects in the paint and varnish coating must be restored with the same paint and varnish materials that were used to paint metal structures at the manufacturer.

3.4. Before use, paint and varnish materials should be stirred until the sediment has completely risen. Preparation of working compositions and application of paints and varnishes is carried out in accordance with the Table.

3.5. Before application, paint and varnish materials must be brought to working viscosity and filtered through a sieve (GOST 6613).

3.6. Working viscosity is determined according to GOST 8420 using a VZ-246-4 viscometer.

3.7. When applying primer to bolted joints, it is necessary to use a nozzle with a small “torch” angle (30º - 40º), applying primer to the bolts and ends of the plates from all sides. In hard-to-reach places (where it is not possible to apply primer from all sides to the surface to be painted), apply a strip layer of primer with a brush.

3.8. At assembly joints, it is allowed to increase the thickness of the paint coating.

3.9. After applying primer to the surfaces of the installation joints and presenting the primed surfaces, coating layers are applied.

3.10. Coating system used:

“Halopolim - 02” + “Vinicolor - 62” - used for painting lighting masts

Table 1.

Technological parameters for applying paint and varnish coatings

3.11. Preparation and application of Halopolim-02 primer.

3.11.1. "Halopolim-02" is a two-component primer composition based on chlorosulfonated polyethylene, cured with a mixture of amine compounds in organic solvents.

3.11.2. Components “A” and “B” are mixed immediately before applying the composition to the surface to be protected. For 1000 gr. component “A” is introduced 150 g. component "B". The introduction of component “B” into component “A” is carried out with continuous stirring. After introducing component “A” into component “B”, the mixture must be kept for 60 minutes in order to remove air bubbles; before application, strain through a sieve (GOST 6613)

3.11.3. The shelf life of the composition from the moment of introduction of the hardener is at least 16 hours at a temperature of 20 ° C.

3.11.4. The primer can be applied at air temperatures from 0 °C to +45 °C and relative humidity air up to 80%. The temperature of the protected surface should be 3 °Cabove the dew point.

3.11.5. The primer should be applied in a uniform layer 80 microns thick (2 x 40 microns).

3.12. Preparation and application of Vinikor 62 enamel.

3.12.1. "Vinikor 62" is a two-component vinyl-epoxy enamel cured with amine hardeners.

Vinikor 62 enamel is cured with AF-2 hardeners in a ratio of 100:2.5 (per 100 parts by weight of the base - 2.5 parts by weight of hardener) or with DTB-2 hardener in a ratio of 100:2.2, supplied in complete with enamel.

3.12.2. When opening a container with enamel, if there is a dried film on the surface of the enamel, it must be completely removed from the container.

After removing the film, the enamel must be thoroughly mixed until a non-separating homogeneous mass is obtained until the sediment is completely lifted.

Up to working viscosity at ambient temperature 20± 2 ° The enamel is finished, if necessary, by introducing solvent P4 in an amount of no more than 5%.

3.12.3. After introducing the hardener, the enamel retains its painting properties for 24 hours.

3.12.4. The enamel should be applied in a uniform layer thickness of 80 ¸ 150 microns (2 or 3 layers of 40 - 50 microns depending on the coating system).

3.12.5. Drying time of the coating with natural drying and temperature 18¸ 20 ° C is 24 hours. Drying should be controlled organoleptically by pressing with a finger for 5¸ 6 seconds there should be no traces of primer left on the finger.

3.12.6. Enamel can be applied at air temperatures from 0° to +35° and relative air humidity up to 85%.

4. QUALITY CONTROL OF PAINT COATINGS

General requirements

4.1. The task of the line engineers and the TECHNADZOR representative includes careful operational control of the entire technological process of applying paints and varnishes, including:

Quality of materials used;

Performance of control devices;

Personnel qualifications;

Correspondence climatic conditions requirements of the Technological Regulations for painting work;

Options technological process;

The quality of individual technological operations;

Compliance with safety and environmental regulations.

Incoming inspection of paints and varnishes

Accompanying documentation confirming the compliance of the received material with the ordered one and its quality (certificate, passport, information on the shipping container) must contain the following information:

Brand of material;

Name of the supplier company;

Material color and color code number according to the catalogue;

Date of manufacture and expiration date;

Basic technical characteristics of the material.

The quality of coating materials received from the manufacturer is often assessed by comparing the main technical characteristics specified in the certificate for the batch of materials and the same characteristics in technical documentation manufacturer (specifications, instructions, brochures, etc.). However, in doubtful cases, a representative of the CUSTOMER'S TECHNICAL SUPERVISION has the right to demand testing for certain indicators.

Regarding testing of paint and varnish materials, you should contact the Central Research Institute of CM "Prometey" (Dr. Sc. Pirogov V.D., Ph.D. Sc. Stepanova Irina Pavlovna tel. 274-18-14, 274-17-29, t/fax 274-17-07)

Paints and varnishes in which a surface film, gelatinization or the formation of a solid-dry sediment are observed (which are observed when opening the packaging) are rejected and not allowed into production.

4.3. Painting equipment, control devices, technological equipment, individual means protection must be in working condition, which must be certified in the relevant documents.

4.4. Manufacturers of painting work must have documented qualifications appropriate to the type of work performed.

All personnel must have the necessary knowledge of painting technology, safety precautions and environmental protection.

4.5. When assessing the quality of a painted surface (each layer and the complete coating system), a visual inspection of the entire surface is performed. Individual tests and measurements provided for in the technological documentation (film thickness, adhesion, continuity, degree of drying, etc.) are carried out in such places and with such frequency as to obtain data on the actual values ​​of the measured parameters.

4.6. At each location, at least three measurements are taken and the average value is calculated. Quality criteria for the painted surface for each controlled indicator must be specified in the Technological Regulations and recommendations of the paint supplier.

Climate control

4.7. Monitoring climatic conditions during painting work must be done at least twice per shift, incl. the first time - before starting work. In unstable weather, measurements should be taken every two hours.

4.8. Climate control includes:

Lack of precipitation or its consequences;

Compliance of the air temperature and the surface to be painted with the requirements set out in the Technological Regulations and in the technical documentation for the paint and varnish material used;

Compliance of relative air humidity with the requirements set out in the Technological Regulations and in the technical documentation for the material used;

Possibility of moisture condensation during painting work.

4.9. Air temperature should be measured with mercury or electronic thermometers with precision ± 0,5 ° C. Measurements must be taken in close proximity to the surface to be painted. When performing painting work on outdoors measurements must be taken from both the sunny and shady sides. The obtained air temperature values ​​must be compared with the permissible application temperature values ​​of the used paint and varnish material and make a CONCLUSION about the possibility of performing painting work.

4.10. Relative humidity should be measured:

Aspiration psychrometers or vortex meters with precision± 3 %;

Digital electronic hygrometers with precision measurements± 2% and measurement limit from 0 to 97% in the temperature range from 0 to 70° WITH.

The obtained relative humidity values ​​must be compared with the values ​​​​permissible for the paint and varnish material used and a CONCLUSION must be made about the possibility of performing painting work.

4.11. The temperature of the surface to be painted should be measured with a magnetic contact thermometer with measurement accuracy± 0,5 ° C. It is recommended to take at least one measurement per 10 sq.m. surfaces. Then you should select the lowest and highest value for each area, compare them with the permissible temperatures of the surface to be painted for the paint material used and make a CONCLUSION about the admissibility of painting work.

If necessary, selective painting of those areas that currently meet the requirements for climatic conditions is allowed.

4.12. The probability of moisture condensation on the surface to be painted is determined by:

According to relative humidity values;

Based on the difference between air temperature and dew point;

Based on the difference between the temperature of the surface being painted and the dew point.

4.13. According to ISO 8502-4, if the relative humidity is 85% or higher, the conditions for painting are considered critical as the temperature is less than 3 degrees above the dew point.° WITH.

If the relative air humidity is 80% or the air temperature is 3.4° C above the dew point, then conditions for painting can be considered favorable for approximately the next six hours.

To avoid moisture condensation, the temperature of the surface to be painted must be at least 3° C above the dew point during painting work.

The dew point is determined from the tables given in the ISO 8502-4 standard, based on the measured values ​​of temperature and relative humidity.

4.14. The results of measurements of climatic parameters with the corresponding values ​​must be recorded in the work log.

Control during the application of paints and varnishes

4.15. During the application of paints and varnishes, the following indicators are usually monitored:

Continuity of coating over the entire surface area;

Wet layer thickness;

Dry layer thickness;

Number of coating layers;

Adhesion;

The degree of drying of each coat of coating before applying the next coat.

4.16. Before starting painting work, it is necessary to check the condition of the surface again. If more than 6 hours have passed since cleaning, you must ensure that the condition of the surface meets the relevant requirements.

4.17. Continuity of the coating, i.e. the uniform, gap-free distribution of the paint and varnish material over the surface is usually assessed visually (by hiding power) under good diffused light or artificial lighting.

However, when forming paint and varnish coatings on critical structures (this must be specified by a representative of the CUSTOMER'S TECHNICAL SUPERVISION), the continuity of the coating is controlled instrumentally - using a low voltage continuity detector.

4.18. Coating thickness. During the application of paints and varnishes, the film thickness of each layer and the total thickness of the coating must be monitored. This can be done by measuring the thickness of the wet film first, then (before applying the next layer) the dry film thickness. When applying Vinikor 62 enamel, it is allowed to control the total thickness of the coating.

Based on the thickness of the wet film, you can approximately estimate the thickness of the dry film using the formula:

TSP = TMP · DN/100, where

TMP - wet film thickness (determined using a “comb”);

DN - volume fraction non-volatile substances (%).

For enamel "Vinikor 62" TSP - 2 TMP

However, in practice, direct control of the thickness of the dry film, both layer-by-layer and of the entire coating system, is carried out, since it gives more accurate values ​​of the coating thickness.

4.19. To measure the thickness of coatings on a magnetic substrate, instruments are used that operate on the principle of measuring the magnetic flux between a magnet and a magnetic substrate or the force of separation of a magnet from a magnetic substrate.

All instruments must be calibrated to “0” before use and every 4 hours during use, the upper limit and those thickness values ​​that will preferably be monitored. For this purpose, a set of reference samples is used.

4.20. When monitoring coating thicknesses, the number and location of measurement sites must be such as to provide reliable data on the actual thickness of the paint coating. This should be the subject of agreement between the parties concerned and noted in the technology documentation. Typically, the following ratio is taken between the number of locations for measuring the thickness of the coating and the area of ​​the surface to be painted:

4.21. At each measuring location with an area of ​​about 0.5 m2, at least three measurements are taken and the average value is calculated. To resolve the issue of acceptable coating thickness, the well-known “Rule 90 - 10” is usually applied: 90% of the measured thicknesses must be no less than the thickness specified in the technological documentation; 10% of the measured thicknesses must be at least 90% of the thickness specified in the technological documentation.

If the thickness of the coating is significantly higher than that specified in the documentation, then the issue of admissibility of the coating is decided by the interested parties.

COATING is considered unacceptable if its thickness is more than twice the required thickness.

4.22. Coating adhesion is determined in accordance with GOST 15140-78 or ISO 2409 and ISO 4624 standards. Methods for determining adhesion are destructive and require restoration of the coating in damaged areas. Therefore, the number of measurements is agreed upon by the interested parties and noted in the technological documentation.

Tests are carried out at a temperature (22 ± 2)° C and relative humidity (50 ± 5)% on coated plates. The number of cuts in each direction of the lattice pattern should be 6.

The distance between cuts depends on the thickness of the coating:

With a thickness of up to 60 microns - 1 mm;

from 61 to 120 microns - 2 mm;

from 121 to 250 microns - 3 mm.

4.23. The degree of drying of each coating layer is controlled to determine the possibility of applying a subsequent layer, controlled using the methods of the ISO 1517 standard or tactile methods (touching the fingers).

In practice, such indicators as “dry to touch” and “dry to the touch” are used. These expressions mean:

- “tack-dry” - lightly pressing the coating with your finger does not leave a mark and does not give a sticky feeling;

- “dry to the touch” - carefully feeling the coating with your hands does not cause damage.

4.24. In addition to assessing the coating according to the above indicators, a representative of the CUSTOMER'S TECHNICAL SUPERVISION during the inspection process must visually inspect the entire surface after applying each layer to detect coating defects.

4.25. The appearance of the coating must correspond V class according to GOST 9.407: the coating must not have gaps, cracks, chips, bubbles, craters, wrinkles and other defects that affect protective properties, as well as unpainted areas. Quality control of the appearance of coatings should be carried out by inspecting painted structures. Up to 4 inclusions per 1 dm are allowed 2 . 2 mm in size (or another number of inclusions, if the size of each inclusion and the total size of the inclusions does not exceed 8 mm per 1 dm²) (requirements of GOST 9.032-74 for class V paintwork).

Control of the formed paint coating

4.26. Control of the formed paint coating is carried out to the same extent as control during the application of paints and varnishes.

However, in this case, the drying period of the coating is taken to be the holding period before commissioning, i.e. until the coating reaches optimal physical, mechanical and protective properties.

After complete formation, the coating is subject to 100% visual inspection for the presence of coloring defects.

5. PREPARATION OF DOCUMENTATION

5.1. The implementation of control operations and the results of control are documented at all stages of work on applying paints and varnishes.

In the work journal (JOURNAL OF WORKS on anti-corrosion protection, painting steel structures) foreman (master) or inspector ( responsible person CUSTOMER) daily notes all the work that he had to perform during the day, indicating the date and time.

5.2. Inspection and acceptance certificates are issued for individual stages of work corresponding to the preparation of the surface for painting and, as a rule, the application of each layer of the coating system. The act notes the results of the technological process of applying paints and varnishes and the quality of the formed coatings, including:

brands and quality of materials used;

operability of equipment, technological equipment and control devices;

technological process parameters;

quality of surface preparation for painting and application of each coating layer according to the main indicators;

quality of a fully formed coating in terms of key indicators.

The act makes a conclusion about the compliance of the quality of painting work with the requirements of standards and Technological Regulations and the acceptance of a specific scope of work.

In case of any deviations from the requirements of the standards or technological Regulations for painting work that has not been corrected based on the comments of the resident engineer (inspector), a NOTICE of violation of the requirements of regulatory documents is issued.

5.3. Upon completion of painting work, i.e. upon acceptance by the CUSTOMER's TECHNICAL SUPERVISION representative (inspector) of the fully formed paint and varnish coating, a summary report on quality control of painting work at the facility is drawn up. The summary report contains all the basic information about the organization of work and the values ​​of the main parameters for the entire technological process. If necessary, photographs of the most characteristic (or controversial) areas of the cleaned or painted surface are attached to the summary report.

6. SAFETY REQUIREMENTS AND INDUSTRIAL SANITATION.

6.1. The painting process must be carried out in accordance with GOST 12.3.005-75, SNiP 12-09, as well as “ Sanitary rules for painting work using hand sprayers" M 991-72, approved by the USSR Ministry of Health dated September 22, 1972.

6.2. When preparing the surface for painting, it is necessary to comply with the safety requirements in accordance with GOST 9.402-80.

6.3. In warehouses and painting areas, work involving the use of open flames, sparks, smoking, etc. is not allowed. Areas must be equipped with foam fire extinguishers, sand boxes and other fire-fighting equipment.

6.4. Production personnel should not be allowed to carry out painting work without personal protective equipment that meets the requirements of GOST 12.4.011-89.

6.5. Workers carrying out painting work must wear special clothing. Workwear that has been doused with solvents or paints and varnishes should be immediately replaced with clean ones.

6.6. To protect the respiratory system from exposure to paint mist and solvent vapors, workers must use respirators such as RU-60M or RPG-67, as well as safety glasses.

6.7. When carrying out painting work in a “closed” space, it is necessary to use gas masks or specialized helmets with forced air supply.

6.8. When working in gas masks, workers should have a supply of replacement “tanks”.

6.9. Lighting in boxes must be explosion-proof or headlamps can be used.

6.10. To protect the skin of the hands, it is necessary to use rubber seals or ointments and pastes in accordance with GOST 12.4.068-79 type IER-1, silicone cream, etc.

6.11. Containers containing paints and varnishes and solvents must have stickers or tags with the exact name and designation of the materials. The container must be in good condition and have tight-fitting lids.

6.12. Sawdust, rags, wiping ends, rags contaminated with paints and varnishes and solvents should be placed in metal boxes and taken to specially designated areas at the end of each shift.

6.13. Near the workplace there should be pure water, freshly prepared saline solution (0.6 - 0.9% sodium chloride solution), clean dry towel, cleaning material.

6.14. If solvent or paint material gets into your eyes, you should immediately rinse your eyes with plenty of water, then saline, and then consult a doctor.

6.15. After finishing work, it is necessary to clean the workplace, clean work clothes and protective equipment.

6.16. In each shift, special persons must be allocated and trained to provide first aid.

APPLICATION

(required)

Coating continuity - this means uniform coverage without gaps. An quality control specialist evaluates it visually in daylight or electric light. The coating must be continuous, with good adhesion to the metal, without drips, wrinkles, sagging, or foreign debris. When applying the coating, we measure the thickness of the wet layer using a comb-thickness gauge

Immediately after applying the paint, immerse the comb in the coating and wait a few seconds.

The difference in elevation between the wet and dry layer will be equal to the thickness of the coating. The method is simple and reliable. And the thickness of the coating is guaranteed to be strong, reliable and durable.

Drying degree — is controlled by the quality manager of the painting area using ISO 1517 methods or the tactile “touch of fingers” method.

This is necessary to determine the possibility of applying a re-coat. Can be determined by the drying time specified by the paint supplier under certain conditions - humidity, temperature and ventilation.

The following indicators are used:

• Dries to a tack - light pressure with a finger leaves no trace and does not feel sticky.
• dry to the touch - if you carefully touch the coating, no damage will occur.

IN modern world corrosion of metals and their protection from corrosion is one of the most important scientific, technical and economic problems. The condition of metal structures in different regions largely depends on the influence of the atmosphere. The development of industry and, as a consequence, growing atmospheric pollution causes intense corrosion of metal structures, so the issue of anti-corrosion protection arises.

RED DUST

The main cause of corrosion damage to metal structures is spontaneous physical and chemical destruction and transformation useful metal into useless chemical compounds. Most environmental components, whether liquids or gases, contribute to the corrosion of metals; Constant natural influences cause rusting of steel structures, damage to car bodies, the formation of pitting (etching pits) on chrome coatings, etc. The rate of corrosion development in depth can reach 0.01 -0.2 mm per year. This problem forces specialists to think and compare the costs of increasing the price of metal (replacement or restoration of metal structures) with the costs of their timely and high-quality painting.

FROM PRIMER TO FINAL COAT

The applied protective coatings ensure the strength and durability of structures and serve as reliable protection of metal structures from environmental influences. First of all, such protection can be achieved using paints and varnishes. The selection of the type of paint and varnish materials and coating system depends on the specific type of metal structure, taking into account the condition of the structure, the degree of destruction of its surface, corrosion hazard, environmental conditions during the work, the expected period of protection and the cost of the coating. The most effective are multilayer paint coatings. Multilayer paint and varnish coatings, which prevent the penetration of moisture, aggressive gases and liquids to the metal surface, usually consist of layers of primer and enamel. The traditional three-layer exterior coating system has next lineup: the primer layer ensures adhesion to the substrate, the second layer has barrier properties and prevents the penetration of the aggressive environment into the metal. The finishing spray also has barrier properties; in addition, it also has high decorative qualities and UV resistance.

BENCHMARK - INTERNATIONAL STANDARD

There are many paints and varnishes on various bases: acrylic, alkyd, epoxy, polyurethane, etc. The standard durability of the paintwork - 15 years or more - will provide protection polymer materials imported production based on epoxy and polyurethane resins.

Efficiency when choosing a paint coating can be determined from the ratio of the cost of preparation square meter surface to guaranteed durability of the coating. In turn, the service life of protective coatings is also determined by many factors. The most important are: the quality of surface preparation for painting and compliance of the characteristics of the selected paint coating with the conditions in which the coating will be used.

The design of anti-corrosion protection (ACP) of metal structures when using imported paints and varnishes must be carried out taking into account international ISO standards, which take into account all factors affecting the durability of the paint.

According to the international standard ISO 12944, the following service life of paint and varnish coatings is defined: low (up to 5 years), medium (from 5 to 15 years) and high (more than 15 years). When choosing a particular coating, as well as required quantity It is recommended to refer to IS012944 for paint layers. IN this document Coating systems based on various binders with various fillers and for environmental categories of varying aggressiveness are indicated.

DURATION IS SMALL

An important point in the design of AKZ is the preparation of the surface for painting. There are several methods for preparing the surface of the substrate before applying paintwork: manual (scrapers, metal brushes) and mechanized cleaning (breakers, cutters, electric and pneumatic tools, etc.), hydrodynamic cleaning under high (up to 1500 bar) water pressure, thermal (gas flame) cleaning (combustion temperature 400-500 °C), chemical cleaning(chemical etching, degreasing), abrasive blasting (under high pressure up to 14 bar of air-abrasive mixture).

Manual cleaning with scrapers and brushes remains the most common in Russia today. The manual cleaning method seems to be the cheapest for the customer only at first glance, but in the future it will be necessary to repaint metal structures many times, since the service life of paintwork when manual cleaning is used is short - up to 2-3 years. This method does not allow the removal of mill scale from the metal surface, which firmly adheres old paint and rust, does not allow creating the surface relief necessary for adhesion. IN international standard ISO 8501 reflects two levels of surface preparation for painting: St 2 and St 3.

THE BEST OPTION

The most productive and effective way surface preparation before applying paintwork is abrasive blasting. This method allows you to remove mill scale and old coatings from the metal surface, giving the surface a relief that is so necessary for good adhesion of the paint and varnish material. The ISO 8501 standard regulates four degrees of surface preparation using the abrasive blasting method: Sa 1, Sa 2, Sa 2.5, Sa 3. The method is based on the following: abrasive particles flying out of the nozzle with high speed(up to 150 m/s) and kinetic energy, upon impact with the metal surface, rust, mill scale, existing coatings and other contaminants are removed. At the same time, the surface acquires a characteristic relief, which contributes to better adhesion coatings with metal.

After abrasive blasting, before applying paints and varnishes, the surface should be cleaned of any dust that has formed. compressed air.

Advantages of abrasive blasting:

But there are also disadvantages:

Abrasive blasting is one of the most common methods for cleaning steel surfaces in the world. In European countries, any newly manufactured structures are subject to mandatory abrasive blasting. According to standard scheme All products are cleaned at the factory, coated with primer and transported to the installation site. After installation is completed, the joints are cleaned and primed, then all structures are painted with finishing layers of paint and varnish.

In Russia, many large enterprises are switching to AKZ technology (for example, NPO Mostovik - Omsk, MMC Norilsk Nickel, Lukoil, etc.).

When repair painting or anti-corrosion work is needed on already installed structures, mobile abrasive blasting complexes, specialized painting equipment and specialized teams with mountaineering training.

EQUIPMENT

Abrasive blasting complexes include: compressor equipment (for example Adas Sorso, Kiss and others) for the production and supply of compressed air (from 7 to 14 bar), abrasive blasting machines (Contracor, Airblast) - boiler tanks where abrasive and air are mixed, air dryers, main hoses, special nozzles (venturi), as well as special clothing for the sandblaster (helmet with air supply and suit). Specialized painting equipment includes; airless spraying units with paint pressure in the main hose up to 350-500 bar, high-pressure hoses, paint guns.

STAFF

Specialized teams should consist of workers with multiple specialties: sandblaster, painter, compressor unit operator, and if work is carried out at height, then have special training and height tolerance.

TECHNOLOGY

Work on anti-corrosion protection of metal structures using the abrasive blasting method is mainly carried out using the following technology:

Degreasing the surface of metal structures is always carried out before using abrasive blasting, since unremoved contaminants will be driven into the metal surface by a jet of abrasive, and will subsequently cause peeling of the coating from the substrate. Degreasing should be carried out by wiping with a rag soaked in a solvent until the fat is completely removed.

Abrasive blast cleaning of metal structures is carried out to degree Sa 2.5 according to ISO 8501, using abrasive blasting systems. Most often, disposable granulated slag (granche varnish - recovered waste from metallurgical production) with a particle fraction of 0.5 to 3 mm is used as an abrasive. This removes the following contaminants: mill scale, old paintwork, rust.

After cleaning, the surface acquires a gray steel color, a certain roughness Rz = 70-170 microns. To reduce the size of the roughness, the fraction of abrasive particles is changed - the content of particles with sizes from 1 to 1.5 mm in the total mass is increased, in this case the roughness is most acceptable Rz = 70-110 microns. At the same time, the consumption of paint and varnish material per 1 m2 is noticeably reduced.

Dust removal of the surface is carried out with compressed air with a pressure of up to 6 bar. To ensure maximum adhesion between layers of paint and varnish material, dust removal is carried out before applying each layer of paint and varnish.

The application of paint and varnish materials is carried out by professional painters using airless application units, for example Graco, Wagner, Wiwa. The paint and varnish material is supplied under high pressure and sprayed through a special nozzle onto the prepared surface. The priming is carried out up to the overlap of the upper points of the surface relief until a continuous, even film of the pound coating is formed. If necessary and the thickness of the coating is maintained, an additional layer of primer is applied.

A prerequisite for high-quality anti-corrosion protection after applying a primer is additional painting (strip painting) of sharp edges, edges and welds on which the paint layer is insufficiently thick.

The application of topcoat finishing layers of paint and varnish materials is carried out in compliance with the regimes in accordance with technical regulations from paint and varnish manufacturers. The final coating is applied as a continuous, even film, controlling the thickness of the wet layer throughout the entire painting process.

QUALITY CONTROL

The implementation of each stage of the technology is accompanied by quality control of the work and climatic conditions during its implementation. This procedure is mandatory and necessary when performing every technological operation, starting from assessing the initial condition of the treated surface to handing over the finished anti-corrosion coating.

Protecting metal surfaces from rust is a major challenge in ensuring their long service life. Destructive natural influence and aggressive environments gradually disrupt the original appearance of products and weaken their quality.

Therefore, it is not surprising that anti-corrosion painting of metal structures very often comes to the fore.

The photo shows painting of complex structures

What is it for

Using special paints and varnishes to protect any metal surfaces is the simplest and most affordable way increase their resistance to the environment and operating conditions.

Such coatings have the following advantages:

• easy to apply;
• allow you to obtain coatings of any color;
• make it possible to process complex and large metal structures;
• the price of the material is significantly lower than other types of protective coatings.

Advice: if you are not satisfied with the estimate provided for painting metal structures by any company, you can turn to others or do the work yourself.

Application of anti-corrosion protection of metal structures

1. Anti-corrosion coatings ensure long and reliable protection from the appearance of rust on the surface:

• steel pipes;
• pipelines;
• garages;
• metal products;
• mechanisms and machine parts.

1. Paints are used for coloring:

• steel structures;
• equipment;
• construction and agricultural machinery.

1. Wear-resistant coatings allow you to obtain long-term anti-corrosion protection of external surfaces:

• pipelines;
• hydraulic structures and bridges;
• building metal structures;
• platforms and overpasses;
• steel containers;
• power line supports;
• storage;
• tanks, as well as metal structures operating in aggressive atmospheres.

Tip: by using anti-corrosion paint, you can ensure reliable protection of metal surfaces from rust and significantly increase their service life.

Painting of metal structures

GOST for painting metal structures provides not only for protecting products from the environment, including from UV radiation or chemical and temperature exposure, but also for giving them a beautiful appearance. At first glance, painting metal structures according to SNiP may seem simple process, in fact, this is not at all true.

The technology for painting metal structures involves cleaning the base before applying it to ensure reliable adhesion of the metal to the enamel. You should especially take seriously surfaces that have already been painted. It is necessary to thoroughly clean them from the old coating, otherwise the new one will have a short service life.

Main stages of work:

• surface preparation;
• removal of fatty deposits;
• applying primer;
• coloring.

Tip: When cleaning metal surfaces, use abrasive equipment while following safety precautions and wearing eye protection.

You cannot do without a cleaning procedure, since there is always some contamination on the surface of the material. Because of this, the primer or enamel will not be able to “stick” to it and will roll off it, or the layer will turn out to be non-uniform, which will affect the quality of the coating.

When painting metal structures, there are two main directions:

• painting new products that have not been painted before;
• repair work.

At the second stage, the instructions prescribe mandatory application to the surface. From quality this process will depend on the ability of “sticking” (adhesion) between the base and finishing coat. To do this, use red lead or metal paint diluted with white spirit.

Remember, preparation for painting takes significantly more time than the painting process itself. After applying the primer, you need to wait until it dries.

Coatings

Today, inorganic zinc coatings (polyurethane or acrylic) are widely used. An alternative is hot-dip galvanizing.

These materials can react with the metal and protect it from corrosion. Very often this process is called “cold galvanizing”. No other paints have these characteristics.

In this case, the calculation of the area to paint metal structures depends on the mass. Such coatings are very economical to use. When protecting steel, their components act by the galvanic method, and a layer of zinc hydroxide begins to form.

Spreading over the metal surface, it fills all the pores that formed during the zinc reaction.

Zinc hydroxide then forms zinc carbonate by reacting with carbon from the atmosphere. Given chemical compound insoluble and is an impenetrable barrier to moisture and rust.

Conclusion

Protecting metal from rust is one of the main areas of anti-corrosion treatment of materials. Painting metal structures at height and on the ground with special paints makes it possible to extend their maintenance-free service life. The video in this article will help you find Additional information on this topic.

Anti-corrosion protection metal structures

Protection of metal structures from corrosion is carried out in accordance with SNiP 2.03.11-85 “Protection building structures from corrosion." The protection of building structures should be carried out by using materials that are corrosion-resistant for the given environment and by performing design requirements(primary protection) by applying metal structures to the surface, oxide, paint and varnish, metallization-varnish-colorful as well as the use of electrochemical methods. The most common scheme for protecting metal structures in production is as follows: primer and enamel painting. The number of layers applied and the group of paints and varnishes depends on the aggressiveness of the environment in which the structures being manufactured will be used. Designs must be primed in one layer, subject to the application of all or part of the coating layers: when applying all coating layers at the installation site, priming should be provided: for structures of buildings and structures for industries with slightly aggressive environments - in two layers (one layer with a thickness of at least 20 µm at the manufacturer and one layer at the installation site) for structures of buildings and production facilities with moderately aggressive and highly aggressive environments - in two layers in production; and mastic coatings, lubricants, film, facing and other materials (secondary protection)

Table 1. Paints and varnishes for protecting steel structures from corrosion.

Hot galvanizing and hotter aluminizing method of immersion in the melt must be provided for protection against corrosion of steel structures: with bolted connections, from an open profile with butt welding and fillet welds, as well as bolts, washers, nuts. This method of corrosion protection may be provided for steel structures with welding overlap subject to continuous scalding along the contour or ensuring a guaranteed gap between the welded elements of at least 1.5 mm. Also in Lately The method of “cold” galvanizing of VMP, by applying zinc-filled compositions, has become widely used. Coatings based on zinc-rich compositions contain more than 82 wt.% metallic zinc and provide sacrificial (cathodic) protection of steel along with zinc coatings obtained by hot-dip galvanizing and thermal spraying.

Table 2. Protection schemes using the method of “cold” galvanizing of metal structures located in the open air and under a canopy.