Common causes of rust are as follows:
1. Placed in a humid environment for a long time, such as being soaked in water or wet land for a long time.
2. Chemical residues on the surface, such as chemicals, salt, etc.
3. Long-term exposure to the atmosphere, such as automobile engine casing pipes, pipes, etc.

So what are the treatment methods for casing pipe rust?
Mechanical rust removal method
1. Grinding method: Use tools such as sandpaper or grinding wheels to grind and remove the rust layer on the surface. Suitable for smaller rust spots.
2. Sandblasting method: Use a high-speed sandblasting machine to completely remove the rust layer on the surface. Suitable for casing pipes with more serious surface rust spots.

Chemical rust removal method
1. Pickling method: Use acidic substances to treat the surface of the casing pipe to chemically decompose the rust layer. However, it should be noted that when using the pickling method, the concentration and use time of the acidic substance must be strictly controlled to avoid corrosion of the casing pipe itself.
2. Electrolysis method: Place the casing pipe in the electrolyte, and use the current to electrolyze and remove the rust layer. The treatment effect is more thorough than the pickling method.

Coating protection method
Applying a layer of anti-rust paint or anti-rust oil on the surface of the casing pipe can effectively prevent the casing pipe from rusting again. However, it should be noted that the coating should be uniform and the thickness should be moderate, otherwise it will affect the normal use of the casing pipe.

Summary
In short, the treatment method for casing pipe rust varies from case to case, and the corresponding treatment method should be selected according to the specific situation. At the same time, attention should be paid to maintenance to prevent the casing pipe from rusting and extend its service life.