Common problems during the production and processing of coated steel pipes

1. Welding seam defects: Welding seam defects are serious and need to be compensated by manual mechanical grinding. The resulting grinding marks will cause the surface to be uneven and affect the appearance. Only pickling and passivating the welds also result in uneven surfaces.

2. Scratches are difficult to remove: the overall pickling and passivation cannot remove various scratches produced during the processing, and it cannot remove the carbon steel and spatter that adhere to the surface of the plastic-coated steel pipe due to scratches and welding spatter. and other impurities, leading to chemical corrosion or electrochemical corrosion and rust in the presence of corrosive media.

3. Uneven grinding and polishing passivation: Pickling and passivation treatment are performed after manual grinding and polishing. For workpieces with larger areas, it is difficult to achieve a uniform treatment effect and an ideal uniform surface cannot be obtained. Moreover, the cost of labor hours and auxiliary materials are also higher.

4. Limited pickling ability: Pickling passivation paste is not omnipotent. It is difficult to remove the black oxide scale produced by plasma cutting and flame cutting.

5. The scratches caused by human factors are relatively serious: During the hoisting, transportation, and structural processing processes, the scratches caused by human factors such as bumping, dragging, and hammering are relatively serious, which makes the surface treatment more difficult, and also causes rust after treatment. main reason.

6. Equipment factors: Scratches and creases caused during the rolling and bending process of profiles and plates are also the main reasons for rust after treatment.

7. Other factors: During the procurement and storage process of plastic-coated steel pipe raw materials, the bumps and scratches caused by hoisting and transportation are also serious, which is also the cause of rust.