Threeway Steel Co., Ltd
E-mail: email@example.comAddress: 22nd Floor, Royal Wing Tower, Long Champ International Building, No.9 Xiangfu Road, Changsha, Hunan, China, PC: 410116
1. Weld defect:
Welding defects are more serious, which can be compensated by manual mechanical grinding treatment methods, and the resulting grinding marks will cause uneven surface and affect aesthetics. Only pickling and passivating the welding seam will also cause uneven surface.
2. Scratches are difficult to remove:
The overall pickling and passivation can not remove all kinds of scratches generated during the processing, and can not remove carbon steel, splashes and other impurities that adhere to the surface of the plastic-coated steel pipe due to scratches and welding splashes, resulting in rust by chemical corrosion and electrochemical corrosion under the presence of corrosive media.
3. Uneven polishing and polishing passivation:
After manual grinding and polishing, pickling and passivation treatment is performed. It is difficult to achieve a uniform and uniform effect on a large-area work-piece, and an ideal uniform surface will not appear. And the cost of working hours and the cost of auxiliary materials are also higher.
4. Limited pickling capacity:
Pickling passivation paste is not omnipotent, and it is difficult to remove black plasma due to plasma cutting and flame cutting.
5. The scratches caused by human factors are more serious:
In the process of lifting, transportation and structural processing, scratches caused by human factors such as bumps, dragging, and hammering are more serious, which makes the surface treatment more difficult and is also the main cause of rust after treatment.
6. Equipment factors:
In the process of bending and bending of profiles and plates, the scratches and creases caused are also the main causes of corrosion after treatment.
7. Other factors:
During the procurement and storage of plastic-coated steel pipe raw materials, bumps and scratches due to lifting and transportation are also serious, which is also one of the causes of rust.