Spiral steel pipe is made from steel coils and extruded using automatic double-wire, double-sided submerged arc welding. The strip is fed into the welded pipe mill. After passing through multiple rollers, the strip is gradually rolled into a round tube blank with an open gap. The reduction of the pinch rollers is adjusted to maintain the weld gap at 13mm, and the weld ends are flush.
How to treat brown rust on the surface of spiral steel pipe? This is actually a misconception based on a lack of understanding of spiral steel pipe. Spiral steel pipe can rust under certain conditions. Spiral steel pipe resists atmospheric oxidation, meaning it does not rust. It also resists corrosion in acids, alkalis, and saline media, meaning it is corrosion-resistant. For example, 304 spiral steel pipe has excellent corrosion resistance in dry, clean environments. However, if it is moved to coastal areas, where sea fog contains a large amount of salt, it will rust quickly. 316 spiral steel pipe, on the other hand, performs better. Therefore, it is not a type of spiral steel pipe that is completely corrosion-resistant and will not rust in any environment.
Spiral steel pipes form a very thin, strong, dense, and stable chromium-rich oxide film (protective film) that prevents oxygen penetration and oxidation, providing corrosion resistance. However, if this film is continuously damaged, oxygen atoms from the air or liquid will continue to penetrate, or iron atoms from the metal will continue to separate, forming loose iron oxide, and the metal surface will continue to rust. This surface film can be damaged in many ways, but the following are more common in everyday life:
1. Dust accumulates on the surface of spiral steel pipes, containing other metal elements or foreign metal particles. In humid air, the connections between the spiral steel pipes and condensed water connect them like a miniature battery, generating an electric current. This chemical reaction destroys the protective film, a process known as electrochemical corrosion.
2. Organic juices (such as melon, vegetable, noodle soup, and spit) adhere to the surface of spiral steel pipes. In the presence of water and oxygen, organic acids form, which can corrode the metal surface over a long period of time.
3. In polluted air (such as atmospheres containing large amounts of sulfides, carbon oxides, and nitrogen oxides), it can come into contact with condensed water, forming spots of sulfuric acid, nitric acid, and acetic acid, causing chemical corrosion.
4. The surface of spiral steel pipes containing acids, alkalis, and salts (for example, alkaline water and lime water splashed onto decorative walls) can cause localized corrosion.
Post time: Sep-09-2025