Does the anti-corrosion coating of pressure vessels need to be repaired immediately after being damaged?

Situations that require immediate repair
1. Severe damage
When the anti-corrosion coating falls off or peels off over a large area, or has deep and dense cracks, resulting in a large area of ​​the container base metal being exposed, the corrosive medium will directly contact the metal and quickly cause corrosion, which must be repaired immediately.
If the coating has a large number of bubbles and has broken, or is severely powdered, and a large amount of powder falls off when wiped by hand, it indicates that the coating has basically lost its protective properties and should be repaired immediately.
2. Highly corrosive media
If the medium in the container is a strong acid, strong alkali, strong oxidizing substance or other highly corrosive medium, even if the anti-corrosion coating is only damaged in a small area, it may cause serious corrosion to the container in a short time and needs to be repaired immediately.
For highly toxic media, once the coating is damaged and the media is at risk of leakage, it will cause great harm to personnel and the environment and must be repaired immediately.
3. Harsh operating conditions
When pressure vessels operate under harsh conditions such as high temperature, high pressure, and high flow rate, coating damage will aggravate the impact of factors such as pressure and temperature on the substrate, accelerate corrosion and reduce material performance, and should be repaired immediately.
When the container is under frequent alternating load conditions, coating damage may cause stress concentration, resulting in defects such as cracks in the container, which must be repaired as soon as possible.
Situations where repairs can be made at an appropriate time
1. Minor damage
The coating has only a few fine cracks, and the cracks do not penetrate the coating, and there is no obvious exposure of the substrate metal. Through testing, it is confirmed that the protective performance of the coating is still basically good, and repairs can be arranged at an appropriate time.
There is a small area of ​​discoloration and slight loss of gloss on the surface of the coating, but there are no other obvious signs of damage. After evaluation, it does not affect the overall anti-corrosion performance of the coating. It can be temporarily not repaired, but monitoring should be strengthened.
2. Weakly corrosive media
The medium in the container is a non-corrosive or very weakly corrosive substance, such as pure water, dry nitrogen, etc. Even if the coating is damaged to a certain extent, it will not cause obvious corrosion to the container substrate in the short term. The appropriate time can be selected for repair according to the production plan and maintenance schedule.
3. Damage to non-critical parts
The damaged part of the coating is in the non-critical part of the pressure vessel, such as far away from stress concentration areas such as welds and pipes, and does not affect the normal operation and safety performance of the vessel. It can be repaired at an appropriate time without affecting production.