The direct external cause of corrosion of the flange and bolt is that there is a corrosive medium between the flange gaps. In the case of no protection of the anti-corrosion coating, the flange metal surface and the bolt will be corroded directly after the contact with water and air.
The method for winding one week with the adhesive tape or the plastic pipe at the joint of the two flanges is used to prevent the external moisture and the sundries from entering the gap of the flange of the human flange, Three aspects were identified after use:
Due to the fact that the full seal cannot be achieved, in the humid environment, there is still condensate accumulation at the flange clearance due to the change of the temperature difference, and the occurrence of corrosion can be accelerated if it cannot be eliminated in time.
After a pair of flange gaps are closed from the outside, once the flange gasket has leakage, it is easy to generate natural gas accumulation, which is not conducive to safe production.
After the adhesive tape and the plastic pipe have been used for a period of time, it is necessary to replace it regularly due to the aging of the material. Therefore, the anti-corrosion treatment is carried out in a way that the adhesive tape or the plastic pipe is used for sealing the flange clearance from the outside, the actual effect is not ideal, and a new anti-corrosion treatment technology and a method for the pipeline flange need to be found.