Corrosion of buried steel pipeline approach
usually, by polyethylene tape protection of buried steel pipeline is no rust or corrosion slower, the life of some steel pipe can reach 40, 50 years, and in some conditions, the buried steel pipeline has amazing corrosion rate, in a few years or more in a short period of time can cause the damage of steel pipe. General corrosion process is: the buried steel pipeline protective layer to produce micro crack and pore, protective layer peeling, harmful medium leaking; Buried steel pipeline corrosion; Steel pipe, serious corrosion; Steel pipe performance degradation, pipe damage. Polyethylene tape anticorrosive processing can generally be considered from two aspects:
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1, according to the corrosion level measures
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corrosion of buried steel pipeline can be divided into: strong, middle or weak, no level 4. In strong corrosion ( A large amount of CO2, SiO2, H2S industrial environment) Conditions, material corrosion speed faster, pipe fittings must be taken to surface isolation protection; Under the condition of medium corrosion, pipeline corrosion to a certain extent, can be used to improve the pipe weight itself, or using simple surface protection; Under the condition of weak corrosion, pipeline corrosion slower, but still need to take some measures; Under the condition of no corrosion, steel pipeline corrosion is very slow or no obvious corrosion marks, components don't have to take protective measures.
2, key processing
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basic level processing: steel structure anticorrosion treatment to qualified at the grassroots level to meet the descaling grade requirements specified in GB/T 8932 Sa2. Level 5, on the surface of the anchor pattern depth 40 ~ 70 microns, to meet the specific requirements of the design drawings. Steel tube surface must be dry and clean.
temperature and humidity: coating of environmental temperature and relative humidity should conform to the requirements of the product, the appropriate environmental temperature in 5 - 38 ℃, relative humidity should not be more than 85%, dew on the surface coating is not allowed. Keep clean and dry surface, and anti-corrosion coating spraying within 4 hours. Such as more than 8 hours or overnight, should besmear again before wrapping tape primer.
: coating thickness should be according to the design requirements, such as common class, strengthen level, strengthen the thickness of the request.