The anti-corrosion of buried seamless steel pipe
is the key procedure to ensure and extend the service life. In order to ensure the firmness of the anti-corrosion insulation layer and the pipe wall, the derusting of the pipeline is the most important.
Generally, according to the factory time, storage and transportation conditions, and the degree of humidity in the climate, the rust on the surface of the American standard steel pipe can be divided into floating rust, medium rust and heavy rust.
Floating rust: Generally, when the factory date is short, when it is not stored in the open air, there is only a small amount of thin rust on the surface of the pipe. The metal luster can be exposed by manual operation such as wire brush, sandpaper and cotton yarn.
Medium rust and heavy rust: When the date of manufacture is long and open storage or multiple transfer and long distance, the surface of the pipe will be oxidized and rusted, and its rust spots will be heavier. In severe cases, the scale will fall off.
Severely rusted pipes are not suitable for sub-water delivery systems. For medium-rust pipes and large batch sizes, mechanical derusting can be carried out by means of descaling machines or mechanical blasting, which can improve labor efficiency and reduce pollution to people and air.
When the anti-corrosion quality is required to be high or the inner and outer walls of the pipe are rusted, the chemical rust removal method can be used to effectively remove the oxides on the inner and outer surfaces of the pipe.
Regardless of the method used to remove rust, the anti-corrosion layer should be treated immediately after rust removal to avoid oxidation and corrosion of the air again.