The polyurea anti-corrosion construction work must be done well, otherwise, even if there is polyurea as an anti-corrosion material, it will be unable to help the corrosion caused by improper construction. The purpose of polyurea anti-corrosion construction is to treat materials that are already prone to corrosion and make them become It is no longer easy to be corroded, so what preparations need to be done when carrying out anti-corrosion treatment, and what is the specific process? , welding and grinding
() The chamfering of components and the welding of edges are processed into arc shapes.
() All welds that will be lined with polyurea are continuous. If there are cracks or depressions, they will be filled by re-welding, and the connecting surfaces will be kept smooth.
) Use cutting and other methods to remove all welding stains on the surface, and finally polish it until smooth.
() All internal and external reinforcements, lifting rings, supports and clamps need to be welded to the container or pipe before lining construction begins. Temporary lifting rings and clamps should be removed before construction, the area should be smoothed, and all corners and edges of the lining should be rounded.
, Sandblasting
() Before sandblasting, use cleaning solution or steam to remove all grease, soil, compounds formed during tempering and cutting, and other contamination on the surface. If cleaning solution is used to clean the surface, clean hot water must be used to wash or evaporate the remaining cleaning agent on the surface. This process will not be performed in this project based on on-site inspection.
() The surface that is not sprayed with polyurea should be protected with plates or other facilities during sandblasting.
) The surfaces that need to be sprayed need to be sandblasted and rubbed. During the treatment process, the air compressor should be kept away from water and oil, and the air pressure from the nozzle should be.
() The friction material used in sand blasting is quartz sand or steel wire cut shot (quartz sand is used in this project). The raw materials for sand blasting contain less than 5% fluoride and less than % active silicon. The raw materials are clean and dry, and the amount of toxic metals, clay, limestone and other impurities contained is not enough to cause harm.
() Environmental conditions for sandblasting: Sandblasting is not performed on surfaces that are wet or may be wet after treatment. When the relative humidity in the air exceeds %, or the surface temperature cannot exceed degrees Celsius, sandblasting will not be performed.
() Surface treatment requirements: Cleanliness must meet the white metal cleaning requirements. The surface roughness exceeds mils and after sand blasting, the surface is free of grease, dust or other dirt. Surface roughness can be confirmed with a micromeasuring tape, and cleanliness can be checked against standards using a visual comparator.
, Construction of sealing primer
() After the sandblasting process is completed and before visible surface rust spots are produced, remove the floating dust on the surface to ensure the dryness of the substrate, and use spray, brush or roller coating methods to apply it evenly Apply primer to the ground.
() Environmental conditions for applying primer:
() The relative humidity of the working area should not be greater than %.
() The surface temperature of the substrate must not be lower than Celsius, and must exceed the dew point temperature of the air in the working area by more than Celsius.
) The surface of the substrate is free of dust, stains and moisture.
, Construction of polyurea coating
() After the primer film is dry, the paint film can be lightly polished with an iron brush, sandpaper, and angular grinding wheel according to the site conditions to obtain a certain roughness. Helps improve the adhesion of polyurea layer and primer.
() Use a special two-component high-pressure spraying machine, and strictly follow the two-component mixing and spraying in a volume ratio of:.
) can be sprayed by the cross method or the pressure gun method. The spraying should ensure a uniform thickness and the film can be formed to the designed thickness in one go. The dry coating is free of bubbles, misalignments, dents, cracks and impurities.
() Environmental conditions for spraying: the relative humidity of the working area is not greater than %, the surface temperature of the substrate is not lower than Celsius, and must exceed the dew point temperature of the air in the working area by Celsius or more, and the surface of the substrate is free of dust, stains and moisture. .
Coating repair: When the coating needs to be repaired due to mechanical wear or damage, the steps are as follows:
() Polish the surface to be repaired, and the polished edge extends outward than the surface to be repaired.
() Remove the floating dust from the polished area and apply repair materials. Note that the patch coating transitions smoothly into the surrounding coating.
Before polyurea anti-corrosion construction, a lot of work is basically to clean the corroded parts, which must be cleaned thoroughly. Also, during the construction process, don’t forget to protect the construction workers and protect them. Sufficient protective equipment must be distributed, and the on-site environment must also be protected. Waste must not be discarded at will, and must be carried out in a well-ventilated area.
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Polyurea anti-corrosion construction technology