According to the design requirements of pipeline anti-corrosion, the anti-corrosion production of steel pipes generally adopts the production method of integrated mechanical flow operation.
After each process is ready, according to the requirements of the three different anti-corrosion layers for the anti-corrosion thickness in the pipeline anti-corrosion, the preheating temperature of the steel pipe coating and the coating thickness of each layer of the anti-corrosion layer should be adjusted in turn on the production line with the test pipe section. Production can only be carried out after all parameters meet the requirements.
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Appearance inspection of steel pipes
1. Before processing, the appearance of the steel pipes should be visually observed by skilled workers to see if the steel pipes have serious mechanical damage, heavy skin, cracks, dents and other defects. Unqualified steel pipes cannot be used, and unqualified ones are marked and returned.
2. If the pipe mouth of the threaded pipe is flat, it should be rounded and repaired in time. If it cannot be repaired, it should be retaliated.
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Rust removal of pipe fittings
1. First, use a pipe grabber to transport the steel pipes that need to be anti-corrosion to the upper pipe platform of the production line, and use a flame heater device to preheat the outer surface of the steel pipe to remove moisture, oil, impurities, etc. on the surface of the steel pipe, which is conducive to improving the rust removal quality of the steel pipe surface.
2. The steel pipe should be rusted by the PW-380 steel pipe shot blasting machine. Before the steel pipe enters the shot blasting room, the pipe head plugs made of rubber pads or thick sponges are plugged at both ends of the steel pipe mouth.
3. After the surface pretreatment is completed, all rust, oil, oxide scale, etc. should be removed.
4. Check the outer surface of each steel pipe, and use appropriate methods to polish the surface defects that may cause coating leakage points. The wall thickness after grinding should not be less than the specified value. Remove or repair the steel pipes with defects.
5. For steel pipes with unqualified rust removal quality, they should be taken off the line in time, the parabolic objects in the pipe should be cleared, and returned to the production line for rust removal again.
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Dust treatment on the surface of steel pipe
1. After the steel pipe is shot blasted and rust-removed, the dust treatment device is used to perform secondary treatment on the outer surface of the steel pipe before the next process of epoxy powder high-voltage electrostatic spraying to remove the rust powder and dust remaining on the outer surface of the steel pipe.
Apply epoxy powder coating within 4 hours. If it exceeds 2 hours or rust appears on the surface of the steel pipe, the surface treatment should be repeated.
2. Clean the dust in the cyclone vacuum cleaner regularly to avoid excessive accumulation and affect the dust removal effect.
3. After starting the dust removal device, check the working condition of the induced draft fan frequently.
4. The dust removal motor should be maintained on schedule to ensure normal operation.
5. Before anti-corrosion production, check the dust treatment on the surface of the steel pipe at least once an hour.
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Preheating of steel pipe
1. The steel pipe after dust treatment should be preheated before epoxy powder coating.
2. Check the water level of the medium frequency circulating water pool
3. According to the feeding speed of steel pipes of different diameters and the predetermined heating stability, the output power value of the medium frequency heating during production is determined.
4. Use advanced temperature measurement to measure the temperature of the steel pipe during preheating to improve the accuracy of the measurement.
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Epoxy powder rolling or spraying
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Adhesive coating and polyethylene winding
1. The coating of the adhesive must be carried out during the epoxy powder gelling process.
2. When using the side winding process, ensure that the polyethylene of the overlapping part and the polyethylene on both sides of the weld are completely rolled and compacted, and prevent the polyethylene surface from being crushed.
After the anti-corrosion layer of the circulating water cooling steel pipe is completed, it must be cooled and fixed in time. The surface of the anti-corrosion layer of the anti-corrosion steel pipe can be cooled in a circulating water coating room. The cooling is carried out in stages.