Requirements for the coating of metal structures. Technological regulations technological regulations for painting metal structures. From primer to finish coat
AT modern world Corrosion of metals and their protection against corrosion is one of the most important scientific, technical and economic problems. The state of metal structures in different regions largely depends on the influence of the atmosphere. The development of industry and, as a result, the growing pollution of the atmosphere causes intense corrosion of metal structures, so the question 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 components environment, 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 pittings (etching pits) on chrome coatings, etc. The rate of development of corrosion in depth can reach 0.01-0.2 mm per year. This problem makes specialists think and compare the cost of metal rise in price (replacement or restoration of metal structures) with the cost of their timely and high-quality painting.
FROM PRIMER TO FINISH
The applied protective coatings ensure the strength and durability of structures and serve reliable protection metal structures from environmental influences. First of all, such protection can be provided with the help of paintwork materials. The selection of the type of paint and varnish materials and the coating system depends on the specific type of metal structure, taking into account the state 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 coatings. Multilayer paint coatings that prevent penetration of moisture, aggressive gases and liquids to the metal surface, as a rule, consist of layers of primer and enamel. The traditional three-layer system for external coating has the following composition: the primer layer provides adhesion to the substrate, the second layer has barrier properties and prevents the penetration of the abrasive environment to the metal. The finish spoy also has barrier properties, in addition, it also has high decorative qualities and UV resistance.
REFERENCE - INTERNATIONAL STANDARD
There are many paint materials available different bases: acrylic, alkyd, epoxy, polyurethane, etc. The standard durability of the paintwork is 15 years or more, they will provide protection polymer materials imported production based on epoxy, polyurethane resins.
Efficiency in the choice of paintwork can be determined from the ratio of the cost of preparation square meter surface for guaranteed coating durability. On the other hand, the service life protective coatings also determined by many factors. The most important are: the quality of surface preparation for painting and the compliance of the characteristics of the selected paintwork with the conditions in which the coating will be used.
The design of anti-corrosion protection (ACP) of metal structures when using imported paintwork materials must be carried out in accordance with international ISO standards, which take into account all factors affecting the durability of painting.
According to the international standard ISO 12944, the following service life of paint coatings is defined: low (up to 5 years), medium (from 5 to 15 years) and high (more than 15 years). When choosing one or another coverage, as well as required amount layers of paint, it is recommended to refer to ISO12944. This document specifies coating systems based on various binders with various fillers and for environmental categories with different aggressiveness.
TERM-SMALL
An important point in the design of AKZ is the preparation of the surface for painting. There are several methods of preparing the surface of the substrate before applying paintwork materials: manual (scrapers, metal brushes) and mechanized cleaning (chippers, cutters, electric, 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 air-abrasive mixture).
Manual cleaning with scrapers and brushes remains the most common in Russia today. manual method cleaning seems the cheapest for the customer only at first glance, but in the future it will be necessary to repaint the metal structures many times, since the service life of the paintwork when applied manual cleaning small - up to 2-3 years. This method does not allow the removal of mill scale from the metal surface, which are firmly attached old paint and rust, does not allow you to create the surface relief necessary for adhesion. The international standard ISO 8501 reflects two degrees of surface preparation for painting: St 2 and St 3.
THE BEST WAY
most productive and effective way surface preparation before applying coatings is abrasive blasting. This method allows you to remove mill scale and old coatings from the metal surface, to give 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 by abrasive blasting: Sa 1, Sa 2, Sa 2.5, Sa 3. The method is based on the following: abrasive particles flying out of the nozzle at high speed (up to 150 m/s) and kinetic energy, upon impact with the metal surface, remove rust, mill scale, existing coatings and other contaminants. At the same time, the surface acquires a characteristic relief, which contributes to better adhesion of the coating to the metal.
After abrasive blasting, before applying paints and varnishes, the surface must be cleaned of dust. compressed air.
Advantages of abrasive blasting:
But there are also disadvantages:
Abrasive blast cleaning is one of the world's most widely used cleaning methods for steel surfaces. In European countries, any newly manufactured structures are subject to mandatory abrasive blast cleaning. According to standard scheme all products are cleaned at the factory, primed and transported to the assembly site. After the installation is completed, the joints are cleaned and primed, then all structures are painted with finishing layers of paintwork materials.
In Russia, many large enterprises are switching to AKZ technology (for example, NPO Mostovik - Omsk, MMC " Norilsk Nickel”, “Lukoil”, etc.).
When is it necessary repair painting or performing anti-corrosion work on already assembled structures, then mobile abrasive blasting systems, specialized painting equipment and specialized teams with climbing training are used.
EQUIPMENT
Abrasive blasting complexes include: compressor equipment (for example, Adas Copco, Kiss and others) for the production and supply of compressed air (from 7 to 14 bar), abrasive blasting machines (Contracor, Airblast) - boilers-tanks where abrasive and air are mixed, air dryers, main hoses, special nozzles (venturi), as well as overalls 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, spray guns.
STAFF
Specialized teams should consist of workers with a plurality of specialties: sandblaster, painter, compressor unit operator, and if work is carried out at height, then have special training and height tolerance.
TECHNOLOGY
Works on anticorrosion protection of metal structures by abrasive blasting are mainly carried out using the following technology:
Degreasing of the surface of metal structures is always carried out before using abrasive blast cleaning, since unremoved contaminants will be driven into the metal surface by an abrasive jet, and subsequently provoke peeling of the coating from the substrate. Degreasing should be carried out by wiping with a cloth soaked in a solvent until the fat is completely removed.
Abrasive blast cleaning of metal structures is carried out to the degree of Sa 2.5 according to ISO 8501, using abrasive blasting systems. Most often, in the form of an abrasive, disposable granular slag is used (granche lacquer - recovered waste from metallurgical production) with a particle fraction of 0.5 to 3 mm. This removes the following contaminants: mill scale, old paintwork, rust.
After cleaning, the surface becomes 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 μm. At the same time, the consumption of paint and varnish material per 1 m2 is noticeably reduced.
Dedusting of a surface is made by compressed air with pressure up to 6 bars. To ensure maximum adhesion between layers of paint and varnish material, dust removal is carried out before applying each layer of paintwork materials.
The application of paints and varnishes is carried out professional painters using airless application units, such as Graco, Wagner, Wiwa. The paintwork material is fed under high pressure and sprayed through a special nozzle onto the prepared surface. Stripping is carried out up to the overlap top points surface relief until a continuous even film of pound coating is formed. If necessary, and observing the thickness of the coating, apply an additional layer of primer.
A prerequisite for high-quality anti-corrosion protection after applying a primer is additional painting (stripe painting) of sharp edges, edges and welds, on which the paint layer has insufficient thickness.
The application of topcoat finish layers of paints and varnishes is carried out in compliance with the regimes in accordance with technical regulations from paint manufacturers. The finish coat is applied in a continuous even film, controlling the thickness of the wet layer throughout the entire staining process.
QUALITY CONTROL
The implementation of each stage of the technology is accompanied by quality control of the work and climatic conditions when executing them. This procedure is obligatory and necessary when performing each technological operation, from the assessment of the initial state of the treated surface to the delivery of the finished anti-corrosion coating.
TECHNOLOGICAL REGULATIONS FOR PAINTING METAL STRUCTURES
1. GENERAL PROVISIONS
1.1. Technological regulations applies to work on anti-corrosion protection by painting the metal structures of superstructures and supports.
1.2. The technological process of painting metal structures at the assembly site includes the following sequential operations:
Surface preparation - degreasing, cleaning from oxides and scale, dedusting;
Restoration of primer layers applied at the factory and damaged during transportation and installation work;
Application of coating layers of paints and varnishes - preparation of working compositions of paintwork materials, application of the required STP 001-95* and TECHNOLOGICAL REGULATIONS the number of layers of the required thickness;
Quality control and acceptance of complex coverage.
1.3. For the technological process, standard and unified tools and equipment should be used.
1.4. To protect metal structures from corrosion at the above-mentioned object, the following coating systems are used:
Coating system (A)
Stelpant-Pu-Zink 80 - 100
Stelpant-Pu-Mica HS 80 micron
Stelpant-Pu-Mica UV80 micron
220 - 240 micron
Coating system (B)
Priming paint material - Stelpant-Pu-Zink 80 - 100 µm (applied at the factory)
Coating material -"Vinikor-62" 120 micron
Complex coating thickness 200 - 220 micron
Coating system (B)
Priming paint material - Stelpant-Pu-Zink 80 - 100 micron
(Applied at the factory)
Intermediate paint material - Stelpant-Pu-Mica HS 80 micron
Coating material -"Vinikor - 62" 80 micron
Complex coating thickness 220 - 240 micron
1.5. The color of the covering layers of the outer surfaces of the metal structures is adopted in accordance with the color scheme.
1.6. The color of the covering layers inside the boxes and pylons is not regulated.
2. SURFACE PREPARATION FOR PAINTING
2.1. Regardless of the type of structures before painting on metal surface there should be no scale, oxides, damaged primer, organic contaminants (oil, grease), burrs, sharp edges, flux residues, welding spatter.
2.2. At this stage, it is necessary to clean the poorly applied paintwork to the bare metal of the structures of the superstructure.
Surface degreasing
2.3. The degreasing process consists in the removal of fatty and oily contaminants under the influence of organic solvents and alkaline degreasing solutions.
2.4. The quality of surface degreasing is checked after complete drying of the surface by one of the methods recommended GOST 9.402-80 The degree of degreasing should be 1.
Mechanical methods for removing poorly applied paint and varnish and preparing welded and bolted field joints.
2.5. The degree of cleaning of the surface prepared for the application of the primer layer should be 1 - 2 according to GOST 9.402-80: When viewed with the naked eye, scale, rust and other non-metallic layers are not detected. Optimum roughness of the metal surface prepared for painting Rz30.
2.6. The required degree of purification from oxides is achieved with the abrasive blasting method. This method provides not only high quality cleaning from all types of contaminants, but at the same time gives the surface a uniform roughness, which helps to increase the adhesion of the coating.
2.7. Calcined (dry, humidity not more than 2%) quartz sand or dried granite screenings with a grain size of 0.5 ¸ 2.0 mm are used as an abrasive material.
The abrasive used must be free of contaminants and other foreign matter. Before using an abrasive in the absence of a certificate, it is imperative to check its purity. To do this, place a small amount of abrasive material in a small glass vessel with distilled water, shake vigorously and leave alone to precipitate. The surface of the water must be free of grease/oil, solids and no discoloration. When measuring the water extract with indicator paper, the pH should be at least 5. There should be no white precipitate in the water when a drop of 5% silver nitrate is added (indication of the presence of chloride salts).
2.8. Compressed air for sandblasting and for air spray painting, must meet the requirements GOST 9.010-80: moisture content and mineral oils in the form of drops are not allowed.
The presence of water and mineral oil in compressed air is determined by an air jet directed to the mirror surface for 3 minutes or to 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 spots should not appear on the surface of the paper and the drawn circles should not darken.
2.9. In case of incomplete removal of flux residues, alkaline slags, splashes and contact fluid(carrying out ultrasonic flaw detection) in the area of welds, accelerated destruction of the coating is possible, therefore, special attention should be paid to surface preparation in the area of welds and avoid using oils as a contact liquid during ultrasonic flaw detection.
2.10. On the surface bolted connections there should not be large drops and streaks of sealant (type "Germokron") used in the assembly of the latter. It is allowed to have a small "roller" along the border of the end face of the lining or washer and the plane of the base metal.
2.11. After sandblasting, the surface of metal structures must be dedusted with a jet of compressed air or with an industrial vacuum cleaner.
2.12. In hard-to-reach places, inside the boxes, surface cleaning can be carried out with manual or mechanical metal brushes. The quality of the cleaned surface must meet the requirements of clause 2.5.
Surface preparation quality control
2.13. Control of the state of the surface of metal structures should be carried out no later than 6 hours after surface preparation, and additionally immediately before painting, if the period exceeds the allowable interval between preparation and painting.
2.14. The surface prepared for painting must be dry, dust-free, free from oil and grease contamination (re-degrease if available), and not have deposits of secondary corrosion formed during surface treatment. After inspecting the surface, an act is drawn up for hidden works characterizing the quality of surface preparation for painting (see Appendix).
3. COATING TECHNOLOGY
3.1. Before painting metal structures, it is necessary to carry out an incoming inspection of paintwork materials for compliance with the requirements normative documents for these materials in accordance with clause 4.2.
3.2. Before starting each work shift, check:
Environmental conditions (air temperature, relative humidity);
dew point temperature;
The absence of moisture and oil contamination on the surface prepared for the application of paints and varnishes.
3.3. Before applying coating materials, it is necessary to check the quality of the primer layers applied at the factory. At the same time, defects in the paintwork must be restored with the same paints and varnishes that were used for painting metal structures at the manufacturing plant.
3.4. Before use, paints and varnishes should be mixed until the sediment is completely raised. The preparation of working compositions and the application of paints and varnishes is carried out in accordance with Table 1.
3.5. Before application, paints and varnishes must be brought to working viscosity and filtered through a sieve ( GOST 6613).
3.6. Working viscosity is determined by GOST 8420 using a VZ-246-4 viscometer.
3.7. When applying a primer to bolted joints, it is necessary to use a nozzle with a small “torch” angle (30º - 40º), applying primer to the bolts and lining ends from all sides. In hard-to-reach places (where it is not possible to apply soil from all sides to the surface to be painted), apply a stripe layer of soil with a brush.
3.8. At the assembly joints, an increase in the thickness of the paintwork is allowed.
3.9. After applying the primer on the surface of the mounting joints and presenting the primed surfaces, top coats are applied.
3.10. Applicable coating systems:
System (A) - Stelpant-Pu-Zink + Stelpant-Pu-Mica HS + Stelpant-Pu-Mica UV - was used to paint part of the outer surfaces of the bridge steel structures.
System (B) - Stelpant-Pu-Zink + Vinicor-62 - is used for painting the external and internal surfaces of the metal structures of the bridge.
System (C) - Stelpant-Pu-Zink + Stelpant-Pu-Mica HS + Vinicor-62 - transitional system between System (A) and System (B).
Table 1.
Technological parameters of applying paint and varnish coatings
|
Paint material |
Solvent |
Application methods |
Number of layers (passes) |
||||
|
Airless |
|||||||
|
Working viscosity, sec |
Thickness of one layer, microns |
Working viscosity, sec |
Thickness of one layer, microns |
System (B) |
System (B) |
||
|
"Stelpant-Pu-Zink" |
Stelpant-Pu-Thinner |
||||||
|
Stelpant-Pu-Mica HS |
"Stelpant-Pu-Thinner" |
||||||
|
Stelpant-Pu-Mica UV |
Stelpant-Pu-Thinner |
||||||
|
Enamel "Vinikor 62" Hardener DTB-2 2.2 parts of hardener per 100 parts of the base, or AF-2 2.5 parts of hardener |
|||||||
3.11. Preparation and application of Stelpant-Pu-Zink primer.
3.11.1. Stelpant-Pu-Zink is a one-component zinc-containing polyurethane primer cured with air moisture.
3.11.2. The preparation of the working composition "Stelpant-PU-Zink" consists in thorough mixing. For airless spraying, paints and varnishes are used with the viscosity as delivered. If necessary, the addition of the Stelpant-PU-Thinner solvent is allowed in an amount of not more than 10%.
3.11.3. The working composition of materials not used during the shift should be poured with a small amount of solvent and tightly closed with the factory cap to prevent an increase in viscosity during storage.
3.11.4. The primer can be applied at air temperatures from 0 °C to +35 °C and relative humidity air up to 95%. Can be applied on damp but not wet surfaces.
3.11.5. The primer should be applied in an even layer with a thickness of 80 ¸ 100 microns (2 x 40 - 50 microns).
3.12. Preparation and application of Vinicor 62 enamel.
3.12.1. "Vinikor 62" is a two-component vinyl-epoxy enamel cured with amine hardeners.
Vinicor 62 enamel is cured with AF-2 hardeners in a ratio of 100:2.5 (for 100 weight parts of the base - 2.5 weight parts of the 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 should be thoroughly mixed until a non-separating homogeneous mass is obtained until the sediment is completely raised.
To working viscosity at an ambient temperature of 20 ± 2 °C, the enamel is brought, if necessary, by the introduction of P4 solvent in an amount of not more than 5%.
3.12.3. After the introduction of the hardener, the enamel retains painting properties for 24 hours.
3.12.4. Enamel should be applied in a uniform layer 80 ¸ 150 microns thick (2 or 3 layers of 40-50 microns each, depending on the coating system).
3.12.5. Drying time of the coating in natural drying and temperature 18 ¸ 20 °C is 24 hours. Drying control should be carried out organoleptically when pressed with a finger for 5 ¸ 6 seconds, no traces of primer should remain on the finger.
3.12.6. Enamel can be applied at air temperature from 0º to +35º and relative air humidity up to 85%.
4. QUALITY CONTROL OF PAINT COATINGS
General requirements
4.1. The task of line engineers and a representative of TECHNADZOR includes careful step-by-step control of the entire technological process of applying paints and varnishes, including:
The quality of the materials used;
Operability of control devices;
Qualification of personnel;
Compliance of climatic conditions with the requirements of the Technological Regulations for painting work;
Technological process parameters;
Quality of execution of individual technological operations;
Compliance with safety and environmental regulations.
Input control paintwork materials
4.2. The incoming control of paintwork materials includes checking the accompanying documentation, inspecting the shipping container and establishing the compliance of the material properties with the requirements specified in the technical documentation for the material.
The accompanying documentation confirming the conformity of the received material with the ordered one and its quality (certificate, passport, information on the shipping container) must contain the following information:
material brand;
Name of the supplier company;
Material color and color number according to the catalog;
Date of manufacture and expiration date;
The main technical characteristics of the material.
The quality of coatings received from the manufacturer is often assessed by comparing the main technical characteristics indicated in the certificate for a batch of materials and the same characteristics in the manufacturer's technical documentation (specifications, instructions, brochures, etc.). However, in doubtful cases, the representative of the TECHNICAL SUPERVISION of the CUSTOMER has the right to require testing for certain indicators.
On the issue of testing paintwork materials, please contact the Central Research Institute of KM "Prometheus" (Dr. Sc. Pirogov V.D., Ph.D. Stepanova Irina Pavlovna tel. 274-18-14, 274-17-29, t/fax 274-17-07)
Paints and varnishes in which there is a surface film, gelatinization or hard-dry precipitation (which are observed when opening the packaging) are rejected and not allowed into production.
4.3. Painting equipment, control devices, technological equipment, personal protective equipment must be in working condition, which must be certified in the relevant documents.
4.4. Paint contractors must have documented qualifications appropriate to the type of work being done.
All personnel must have necessary knowledge on the technology of painting, safety and environmental protection.
4.5. When evaluating the quality of the painted surface (each layer and complete system coatings) is produced visual inspection the entire surface. Separate 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 in order to obtain data on real values measured parameters.
4.6. At least three measurements are taken at each location and an average value is calculated. Quality criteria for the painted surface for each controlled indicator should be specified in the Technological Regulations and recommendations of the paint supplier.
Climate control
4.7. Control of climatic conditions during the execution of painting work must be carried out 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 their consequences;
Compliance of the air temperature and the surface to be painted with the requirements set forth in the Technological Regulations and in the technical documentation for the paintwork material used;
Compliance with the relative humidity of the air to the requirements set forth in the Technological Regulations and in the technical documentation for the material used;
Probability of moisture condensation during painting work.
4.9. Air temperature should be measured with mercury or electronic thermometers with an accuracy of ± 0.5 °С. Measurements must be taken in close proximity to the surface to be painted. When painting outdoors, measurements must be taken from both the sunny and shady sides. The obtained values of air temperature must be compared with the permissible values of the application temperature 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 psychrometers with an accuracy of ± 3%;
Digital electronic hygrometers with a measurement accuracy of ± 2% and a measurement limit of 0 to 97% in the temperature range from 0 to 70 °C.
The obtained values of relative humidity must be compared with the values allowed for the used paint and varnish material 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 an accuracy of ± 0.5 °C. It is recommended to take at least one measurement per 10 sq. m. surface. Then you should choose the lowest and highest value for each area, compare them with the allowable temperatures of the surface to be painted for the paint material used and make a CONCLUSION about the admissibility of the painting work.
If necessary, selective coloring of those areas that currently meet the requirements for climatic conditions is allowed.
4.12. The probability of moisture condensation on the painted surface is determined by:
According to relative humidity values;
By the difference between air temperature and dew point;
By the difference between the temperature of the surface to be 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, since the temperature is less than 3 °C above the dew point.
If the relative humidity of the air is 80% or the air temperature is 3.4°C above the dew point, the conditions for painting can be considered favorable for about six subsequent hours.
To prevent 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 ISO 8502-4 from the measured values of temperature and relative humidity.
4.14. The results of measurements of climatic parameters with the corresponding values should be recorded in the work log.
Control in the process of applying paints and varnishes
4.15. In the process of applying paints and varnishes, the following indicators are usually controlled:
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 coating layer before applying the next layer.
4.16. Before starting painting work, it is necessary to check the condition of the surface again. If more than 6 hours have elapsed since cleaning, check that the surface condition meets the relevant requirements.
4.17. Coating continuity, i.e. uniform, gap-free distribution of the coating material over the surface is usually assessed visually (by hiding power) in good diffused light or artificial lighting.
However, when forming paint coatings on critical structures (this must be agreed by the representative of the CUSTOMER'S TECHNICAL SUPERVISION), the coating continuity is controlled by an instrumental method - using a low voltage continuity detector.
4.18. Coating thickness. In the process of applying paints and varnishes, the film thickness of each layer and the total thickness of the coating must be controlled. This can be done by measuring the thickness first of the wet layer, then (before applying the next layer) of the dry film. When applying Vinicor 62 enamel, it is allowed to control the total thickness of the coating.
From the wet film thickness, the approximate dry film thickness can be estimated using the formula:
TSP \u003d TMP DN / 100, where
WMT - wet film thickness (determined using a "comb");
DN - volume fraction of non-volatile substances (%).
For enamel "Vinikor 62" TSP = 2 TMP
However, in practice, direct control of the dry film thickness is carried out, both layer by layer and the entire coating system, since it gives more accurate coating thickness values.
4.19. To measure the thickness of coatings on a magnetic substrate, devices are used that work 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, to the upper limit and to those thicknesses that will preferably be controlled. To do this, use a set of reference samples.
4.20. When controlling coating thicknesses, the number and location of measurement sites must be such as to obtain a convincing indication of the actual thickness of the coating. This should be the subject of an agreement between the interested parties and noted in the technological documentation. Usually, the following ratio of the number of places for measuring the coating thickness and the area of the surface to be painted is taken:
4.21. At each measurement point with an area of approximately 0.5 m 2, at least three measurements are made and an average value is calculated. To resolve the issue of the admissibility of the coating thickness, the well-known "Rule 90 - 10" is usually applied: 90% of the measured thicknesses must be at least 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 specified in the documentation, then the question of the admissibility of the coating is decided by the interested parties.
A COATING is considered unacceptable if it is more than twice the thickness required.
4.22. Coating adhesion is determined according to GOST 15140-78 or ISO 2409 and ISO 4624. Adhesion testing methods are destructive and require recoating of damaged areas. Therefore, the number of measurements is agreed by the interested parties and noted in the technological documentation.
Tests are carried out at a temperature of (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 the notches depends on the coating thickness:
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 the next layer, controlled according to ISO 1517 standard methods or tactile methods (finger touch).
In practice, such indicators as "drying to tack" and "drying to the touch" are used. These expressions mean:
- "dry to touch" - a slight pressure on the coating with your finger does not leave a trace and does not give a sticky feeling;
- "dry to the touch" - careful touching of the coating with your hands does not cause damage to it.
4.24. In addition to evaluating the coating according to the above indicators, the representative of the TECHNICAL SUPERVISION of the CUSTOMER during the control process must visually inspect the entire surface after applying each layer in order to detect coating defects.
4.25. The appearance of the coating must correspond to class V according to GOST 9.407: the coating must be free of gaps, cracks, chips, bubbles, craters, wrinkles and other defects affecting protective properties, as well as unpainted places. Quality control of the appearance of coatings should be carried out by examining the painted structures. Up to 4 inclusions per 1 dm 2 are allowed. 2 mm in size (or another number of inclusions, if the size of each inclusion and the total size of inclusions does not exceed 8 mm per 1 dm²) (requirements GOST 9.032-74 for class V paintwork).
Control of the formed paintwork
4.26. The control of the formed paint and varnish coating is carried out in the same volume as the control in the process of applying paints and varnishes.
However, in this case, the drying period of the coating is taken to be the exposure time before commissioning, i.e. until the coating achieves optimal physical, mechanical and protective properties.
After complete formation, the coating is subject to 100% visual control for the presence of color defects.
5. DOCUMENTATION
5.1. The performance of control operations and the results of control are documented at all stages of work on the application of paints and varnishes.
In the work journal (JOURNAL OF WORKS on waterproofing, anticorrosion protection, painting of steel structures), the foreman (foreman) or inspector (responsible person of the CUSTOMER) daily notes all the work that he had to perform during the day, indicating the date and time.
5.2. Control and acceptance certificates are drawn up for separate 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;
Efficiency of equipment, technological equipment and control devices;
Technological process parameters;
The quality of surface preparation for painting and the application of each layer of coating according to the main indicators;
The quality of a fully formed coating according to the main indicators.
The act concludes on the compliance of the quality of painting work with the requirements of standards and the Technological Regulations and the adoption of a specific scope of work.
In case of any deviations from the requirements of the standards or the technological Regulations for the performance of painting work, which were not corrected according to the remarks 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. acceptance by the representative of the CUSTOMER'S TECHNICAL SUPERVISION (inspector) of a fully formed paint and varnish coating, a summary report is issued on quality control of the painting work at the facility. The summary report contains all the basic information about the organization of work and the values of the main parameters throughout 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 regulations during painting work using manual sprayers "M 991-72, approved by the USSR Ministry of Health on 09/22/72,
6.2. When preparing a surface for painting, it is necessary to comply with safety requirements for GOST 9.402-80.
6.3. Warehouses and areas for painting works are not allowed to carry out work related to the use of open fire, sparking, smoking, etc. Sites must be provided with foam fire extinguishers, sandboxes and other fire fighting equipment.
6.4. Production personnel should not be allowed to perform painting work without personal protective equipment that meets the requirements GOST 12.4.011-89.
6.5. Workers conducting painting work must work in overalls. The overalls doused with solvent or paints and varnishes should be immediately replaced with clean ones.
6.6. To protect the respiratory organs from exposure to paint mist and solvent vapors, workers must use respirators of the RU-60M or RPG-67 type, as well as goggles.
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 interchangeable "tanks".
6.9. Lighting in the boxes must be explosion-proof or headlamps may be used.
6.10. To protect the skin of the hands, it is necessary to use rubber seals or ointments and pastes according to GOST 12.4.068-79 IER-1 type, silicone cream, etc.
6.11. Containers containing paints and varnishes and solvents must have stickers or tags with the exact name and designation of materials. Containers must be in good condition and have tight-fitting lids.
6.12. Sawdust, rags, cleaning ends, rags contaminated with paints and varnishes and solvents should be placed in metal boxes and taken out to specially designated places at the end of each shift.
6.13. There should be clean water near the workplace, freshly prepared saline solution (0.6 - 0.9% sodium chloride solution), a clean, dry towel, and wiping material.
6.14. In case of contact with the eyes of solvent or paintwork material, immediately rinse eyes with plenty of water, then saline and then see a doctor.
6.15. After finishing work, it is necessary to clean the workplace, clean overalls and protective equipment.
6.16. In each shift, special persons should be allocated and trained to provide first aid.
APPENDIX
(mandatory)
ACT
|
APPENDIX
RELATIONSHIP OF AMBIENT AIR TEMPERATURE AND DEW POINT TEMPERATURE AT A CERTAIN RELATIVE HUMIDITY
APPENDIX
QUALITY CONTROL OF DEGREASING
|
Control method |
Applicability of the method |
Requirement GOST 9. 402-80 for degreasing degree 1 |
|
Surface wettability method |
After degreasing with water and detergent solutions |
The time to break the water film is more than 30 seconds |
|
drip method |
No oil stain on filter paper |
|
|
Wiping method |
After degreasing with aqueous and detergent solutions, organic solvents |
dark spot on a napkin vague, not clearly expressed |
Coating continuity - this means a uniform coating without gaps. The OTC specialist evaluates it visually in daylight or electric light. The coating must be continuous, with good adhesion to the metal, without streaks, wrinkles, sagging, foreign debris. When applying the coating, we measure the thickness of the wet layer using a thickness comb
Immediately after applying the paint, immerse the comb in the coating and wait a few seconds.
The difference between the mark 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 - controlled by the quality manager of the painting area according to ISO 1517 methods or the tactile method "touching the fingers".
This is necessary to determine the possibility of applying a second layer. Can be determined by the drying time specified by the paint supplier at certain conditions— humidity, temperature and ventilation.
Indicators such as
- tack-free - light pressure with a finger leaves no trace and no stickiness is felt.
- dry to the touch - if you carefully feel the coating, then damage does not occur.
TECHNOLOGICAL REGULATIONS FOR COLORING
METAL STRUCTURES OF THE BRIDGE SPAN
1. GENERAL PROVISIONS
1.1. The technological process of painting metal structures at the assembly site includes the following sequential operations:
Surface preparation - degreasing, cleaning from oxides and scale, dedusting;
Restoration of primer layers applied at the factory and damaged during transportation and installation work;
Application of coating layers of paints and varnishes - preparation of working compositions of paintwork materials, application of the number of layers of the required thickness required by STP 001-95 * and TECHNOLOGICAL REGULATIONS, layer-by-layer drying;
Quality control and acceptance of complex coverage.
1.2. For the technological process, standard and unified tools and equipment should be used.
2. SURFACE PREPARATION FOR PAINTING
2.1. Regardless of the type of structure, before painting, the metal surface must be free of scale, oxides, damaged primer, markings, organic contaminants (oil, grease), burrs, sharp edges, flux residues, welding spatter.
2.2. Work on cleaning the surface of metal structures should be started after the completion of all assembly and welding, after correcting defective areas.
Surface degreasing
2.3. The degreasing process consists in the removal of fatty and oily contaminants under the influence of organic solvents and alkaline degreasing solutions.
2.4. The quality of surface degreasing is checked after complete drying of the surface by one of the methods recommended by GOST 9.402-80. The degree of degreasing should be 1.
Mechanical methods for removing oxides
2.5. The degree of cleaning from oxides of the surface prepared for applying the primer layer should be 1 - 2 according to GOST 9.402-80: when viewed with the naked eye, scale, rust and other non-metallic layers are not detected. The optimal roughness of the metal surface prepared for painting is Rz30 (no more).
2.6. The required degree of purification from oxides is achieved with the abrasive blasting method. This method provides not only a high quality of cleaning from all types of contaminants, but at the same time gives the surface a uniform roughness, which helps to increase the adhesion of the coating.
2.7. Calcined (dry, humidity not more than 2%) quartz sand with a grain size of 0.5 is used as an abrasive material.¸ 2.0 mm, or corundum with a grain size of 16 according to GOST 3647.
The abrasive used must be free of contaminants and other foreign matter. Before using the abrasive, it is necessary to check its purity. To do this, place a small amount of abrasive material in a small glass vessel with distilled water, shake vigorously and leave alone for precipitation. There must be no film of grease/oil on the surface of the water, solids and no discoloration should occur. When measuring the water extract with indicator paper, the pH should be at least 5. There should be no white precipitate in the water when a drop of 5% silver nitrate is added (indication of the presence of chloride salts).
2.8. Compressed air intended for sandblasting and for pneumatic spray painting must comply with the requirements of GOST 9.010-80: moisture and mineral oils in the form of drops are not allowed.
The presence of water and mineral oil in compressed air is determined by an air jet directed to the mirror surface for 3 minutes or to 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 spots should not appear on the surface of the paper and the drawn circles should not darken.
2.9. In case of incomplete removal of flux residues, alkaline slags, splashes and contact liquid (ultrasonic flaw detection) in the area of welds, accelerated destruction of the coating is possible, therefore, special attention should be paid to surface preparation in the area of welds and avoid using oils as a contact liquid during ultrasonic flaw detection.
2.10. After sandblasting, the surface of metal structures must be dedusted with a jet of compressed air (preferably with a vacuum cleaner).
Surface preparation quality control
2.11. Control of the state of the surface of metal structures should be carried out no later than 6 hours after surface preparation, and additionally immediately before painting, if the period exceeds the allowable interval between preparation and painting.
2.12. The surface prepared for painting must be dry, dust-free, free from oil and grease contamination (re-degrease if available), and not have deposits of secondary corrosion formed during surface treatment. After inspecting the surface, an act for hidden work is drawn up, characterizing the quality of surface preparation for painting (see Appendix).
3. COATING TECHNOLOGY
3.1. Compressed air intended for pneumatic spray painting must comply with the requirements of GOST 9. 010-80.
3.2. Before painting metal structures, it is necessary to carry out an incoming inspection of paintwork materials for compliance with the requirements of regulatory documents for these materials.
Coating system for corrosion protection of metal structures
Priming paintwork material -...................... FL-03K 50 microns
(Applied at the factory)
Coating material -...................... XV-124 70 microns
Complex coating thickness -...................... 120 microns
Table 1.
Technological parameters of applying paint and varnish coatings
|
Solvent |
Application methods |
||||||
|
Pneumatic |
Airless |
||||||
|
Working viscosity, sec |
Thickness of one layer, microns |
Working viscosity, sec |
Thickness of one layer, microns |
Working viscosity, sec |
Thickness of one layer, microns |
||
|
FL-03K Sikkativ NF-1-4% by weight of undiluted primer |
Solvent, xylene |
||||||
|
Solvent, xylene |
|||||||
3.3. Before starting each work shift, check:
Environmental conditions (air temperature, relative humidity);
dew point temperature;
The absence of moisture and oil contamination on the surface prepared for the application of paints and varnishes.
3.4. Before applying coating materials, it is necessary to check the quality of the primer layers applied at the factory. At the same time, defects in the paintwork must be restored with the same paints and varnishes that were used for painting metal structures at the manufacturing plant.
3.5. Before use, paints and varnishes should be mixed until the sediment is completely raised. The preparation of working compositions and the application of paints and varnishes is carried out in accordance with the table. Before application, paintwork materials must be brought to working viscosity and filtered through a sieve (GOST 6613). Working viscosity is determined according to GOST 8420 using a VZ-246-4 viscometer.
3.6. At the manufacturing plant, two layers of primer paint and varnish material GF-0119 or FL-03K should be applied.
In the case of using FL-03K as a primer, the third layer of FL-03K is applied before applying the top layer, the top layer is applied over the underdried FL-03K layer
3.7. The mode of natural drying of paints and varnishes up to degree 3 is given in the table.
Table 2.
Technological modes of drying paints and varnishes
|
Natural drying |
convective drying |
|||
|
temperature, ° C |
temperature, ° C |
|||
4. QUALITY CONTROL OF PAINT COATINGS
General requirements
4.1. The task of linear engineers includes a thorough step-by-step control of the entire technological process of applying paints and varnishes, including:
The quality of the materials used;
Operability of control devices;
Qualification of personnel;
Compliance of climatic conditions with the requirements of the Technological Regulations for painting work;
Technological process parameters;
Quality of execution of individual technological operations;
Compliance with safety and environmental regulations.
Incoming control of paintwork materials
4.2. The incoming control of paintwork materials includes checking the accompanying documentation, inspecting the shipping container and establishing the compliance of the material properties with the requirements specified in the technical documentation for the material.
The accompanying documentation confirming the conformity of the received material with the ordered one and its quality (certificate, passport, information on the shipping container) must contain the following information:
material brand;
Name of the supplier company;
Material color and color number according to the catalog;
Date of manufacture and expiration date;
The main technical characteristics of the material.
The quality of coatings received from the manufacturer is often assessed by comparing the main technical characteristics specified in the certificate for a batch of materials and the same characteristics in the manufacturer's technical documentation (specifications, instructions, brochures, etc.). However, in doubtful cases, the representative of the CUSTOMER'S TECHNICAL SUPERVISION has the right to require testing according to some indicators.
Paints and varnishes in which a surface film, gelatinization or solid-dry precipitation (which are observed when opening the packaging container) are observed, are rejected and not allowed into production.
4.3. Painting equipment, control devices, technological equipment, personal protective equipment must be in working condition, which must be certified in the relevant documents.
4.4. Paint contractors must have documented qualifications appropriate to the type of work being done.
All personnel must have the necessary knowledge of painting technology, safety and environmental protection.
4.5. When evaluating the quality of the painted surface (each layer and the complete coating system), a visual inspection of the entire surface is carried out. Separate tests and measurements provided for by technological documentation (film thickness, adhesion, continuity, degree of drying, etc.) are carried out in such places and with such frequency in order to obtain data on the actual values of the measured parameters.
4.6. At each location, at least three measurements are made and an average value is calculated. Quality criteria for the painted surface for each controlled indicator should be specified in the Technological Regulations and recommendations of the paint supplier.
Climate control
4.7. Control of climatic conditions during the execution of painting work must be carried out 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 their consequences;
Compliance of the air temperature and the surface to be painted with the requirements set forth in the Technological Regulations and in the technical documentation for the paintwork material used;
Compliance with the relative humidity of the air to the requirements set forth in the Technological Regulations and in the technical documentation for the material used;
Probability of moisture condensation during painting work.
4.9. Air temperature should be measured with mercury or electronic thermometers with an accuracy± 0,5 ° C. Measurements must be taken in close proximity to the surface to be painted. When painting outdoors, measurements must be taken from both the sunny and shady sides. The obtained values of air temperature must be compared with the permissible values of the application temperature 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 psychrometers with accuracy± 3 %
Digital electronic hygrometers with measurement accuracy± 2% and measurement limit from 0 to 97% in the temperature range from 0 to 70° WITH.
The obtained values of relative humidity must be compared with the values allowed for the used paint and varnish material 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 an accuracy of measurement± 0,5 ° C. It is recommended to take at least one measurement per 10 sq. m. surface. Then you should choose the lowest and highest value for each area, compare them with the allowable temperatures of the surface to be painted for the paint material used and make a CONCLUSION about the admissibility of the painting work.
If necessary, selective coloring of those areas that currently meet the requirements for climatic conditions is allowed.
4.12. The probability of moisture condensation on the painted surface is determined by:
According to relative humidity values;
By the difference between air temperature and dew point;
By the difference between the temperature of the surface to be 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, since the temperature is less than 3° WITH.
If the relative humidity is 80% or the air temperature is 3.4° C above the dew point, staining conditions can be considered favorable for about six consecutive hours.
To prevent moisture condensation, the temperature of the surface to be painted must be at least 3° C above dew point during painting work.
The dew point is determined from the tables given in ISO 8502-4 from the measured values of temperature and relative humidity.
4.14. The results of measurements of climatic parameters with the corresponding values should be recorded in the work log.
Control in the process of applying paints and varnishes
4.15. In the process of applying paints and varnishes, the following indicators are usually controlled:
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 coating layer before applying the next layer.
4.16. Before starting painting work, it is necessary to check the condition of the surface again. If more than 6 hours have elapsed since cleaning, check that the surface condition meets the relevant requirements.
4.17. Coating continuity, i.e. uniform, gap-free distribution of the coating material over the surface is usually assessed visually (by hiding power) in good diffused light or artificial lighting.
However, when forming paint coatings on critical structures (this must be agreed by the representative of the CUSTOMER'S TECHNICAL SUPERVISION), the coating continuity is controlled by an instrumental method - using a low voltage continuity detector.
4.18. Coating thickness. In the process of applying paints and varnishes, the film thickness of each layer and the total thickness of the coating must be controlled. This can be done by measuring the thickness first of the wet layer, then (before applying the next layer) of the dry film.
From the wet film thickness, the approximate dry film thickness can be estimated using the formula:
TSP \u003d TMP DN / 100, where
WMP - wet film thickness;
DN - volume fraction of non-volatile substances (%).
However, in practice, direct control of the dry film thickness is carried out, both layer by layer and the entire coating system, since it gives more accurate coating thickness values.
4.19. To measure the thickness of coatings on a magnetic substrate, devices are used that work 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, to the upper limit and to those thicknesses that will preferably be controlled. To do this, use a set of reference samples.
4.20. When controlling coating thicknesses, the number and location of measurement sites must be such as to obtain a convincing indication of the actual thickness of the coating. This should be the subject of an agreement between the interested parties and noted in the technological documentation. Usually, the following ratio of the number of places for measuring the coating thickness and the area of the surface to be painted is taken:
|
Surface area to be painted, m 2 |
Number of measuring points |
4.21. At each measurement point with an area of approximately 0.5 m 2, at least three measurements are made and an average value is calculated. To resolve the issue of the admissibility of the coating thickness, the well-known "Rule 90 - 10" is usually applied: 90% of the measured thicknesses must be at least 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 specified in the documentation, then the question of the admissibility of the coating is decided by the interested parties. A 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 on damaged areas.
Tests are carried out at a temperature (22± 2) ° C and relative humidity (50± 5) % on coated inserts. The number of cuts in each direction of the lattice pattern should be 6.
The distance between the notches depends on the coating thickness:
With a thickness of up to 60 microns - 1 mm;
from 61 to 120 microns - 2 mm;
from 121 to 250 microns - 3 mm.
Therefore, the number of measurements is agreed by the interested parties and noted in the technological Regulations.
4.23. The degree of drying of each coating layer is controlled to determine the possibility of applying a subsequent layer, controlled according to the methods of ISO 1517 or tactile methods (finger touch).
In practice, such indicators as "dry to touch" and "dry to the touch" are used. These expressions mean:
- "dry to touch" light pressure on the coating with your finger does not leave a trace and does not give a sticky feeling;
- "dry to the touch" careful palpation of the coating with hands does not cause damage to it.
In addition to evaluating the coating according to the above indicators, the representative of the TECHNICAL SUPERVISION of the CUSTOMER during the control process must visually inspect the entire surface after applying each layer in order to detect coating defects.
The appearance of the coating must comply with class V according to GOST 9. 407: the coating must not have gaps, cracks, chips, bubbles, craters, wrinkles and other defects that affect the protective properties.
Control of the formed paintwork
4.24. The control of the formed paint and varnish coating is carried out in the same volume as the control in the process of applying paints and varnishes.
However, in this case, the drying period of the coating is taken to be the exposure time before commissioning, i.e. until the coating achieves optimal physical, mechanical and protective properties.
After complete formation, the coating is subject to 100% visual control for the presence of color defects.
5. DOCUMENTATION
5.1. The performance of control operations and the results of control are documented at all stages of work on the application of paints and varnishes.
In the work log (JOURNAL of WORKS on waterproofing, anti-corrosion protection, painting of steel structures), the foreman (master) or inspector (responsible person of the CUSTOMER) daily notes all the work that he had to perform during the day, indicating the date and time.
5.2. Control and acceptance certificates are drawn up for separate 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:
Climatic conditions during the period of work;
Brands and quality of materials used;
Efficiency of equipment, technological equipment and control devices;
Technological process parameters;
The quality of surface preparation for painting and the application of each layer of coating according to the main indicators;
The quality of a fully formed coating according to the main indicators.
The act concludes on the compliance of the quality of painting work with the requirements of standards and the Technological Regulations and the adoption of a specific scope of work.
In case of any deviations from the requirements of the standards or the technological Regulations for the performance of painting work, which were not corrected according to the remarks 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. acceptance by the representative of the CUSTOMER'S TECHNICAL SUPERVISION (inspector) of a fully formed paint and varnish coating, a summary report is issued on quality control of the painting work at the facility. 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.
APPENDIX
(mandatory)
|
ACT Commission consisting of: __________________________________________________________________________ __________________________________________________________________________ inspected and checked the preparation of the metal surface for applying the primer layer in _______________________________________________________ (specify span) on the _______________________________________________________________________ (specify structural element) Surface condition of the above structural element: _______________ __________________________________________________________________________ (indicate the degree of purification from oxides, the degree of degreasing, |
After degreasing with water and detergent solutions |
The time to break the water film is more than 30 seconds |
|
drip method |
No oil stain on filter paper |
|
|
Wiping method |
After degreasing with aqueous and detergent solutions, organic solvents |
The dark spot on the napkin is vague, not clearly expressed |