Weld steel pipe coatings

As we all know, welded steel pipe is prone to corrosion over time in use. With reference to corrosion protection of pipeline in projects, there are many types of coatings and wrapping applied in applications today. As a rule, coatings have two primary functions: decoration and protection which are of considerable economic importance. Functional coatings may be applied to change the surface properties of the substrate, such as adhesion, wetability, corrosion resistance, or wear resistance.

So far, galvanization is very popular used in the steel pipe industry, which forms a hard protection lay around the steel body in production process. For instance, hot dipped galvanized steel pipe is such a typical steel pipe in the steel pipe industry as it is dipped into in a vat of the molten metal or use electroplating techniques in a mill in order to increase the service life of the metal by preventing corrosion for certain applications. Besides, before shipping the pipes, steel pipe manufacturers often coat the galvanized metal with oil to retard reaction of zinc with the atmosphere. When this oil coating wears off, the reaction of zinc with oxygen produces a fine whitish film that changes the color of the metal from gray to an even less appealing whitish-gray. When galvanized steel pipe needs importing, this type of pipe usually has a passivator film that protects the metal from corrosion in the salt-water environment as the metal travels across seas or oceans on cargo ships. When exposed to the exterior, this passivator will weather away in six months; for interior use, it can be removed by etching the surface with a phosphoric acid solution.

In addition, paint coating or powdering coating are another two popular methods to mainly protect welded steel pipe from corrosion, as well as maintain a pretty appearance of pipe in use today. Especially paint systems widely used for steel structures have developed over the years to comply with industrial environmental legislation and in response to demands from bridge and building owners for improved durability performance. In many large building projects, structural steel pipes are painted with specific color to maintain a pretty appearance in use. The protective paint systems usually consist of primer, undercoat(s) and finish coats. Each coating ‘layer’ in any protective system has a specific function, and the different types are applied in a particular sequence of primer followed by intermediate / build coats in the shop, and finally the finish or top coat either in the shop or on site.

DongPengBoDa Steel Pipe Group, as one of the famous steel pipe manufacturers in China, provides various types of steel pipe treatment services, involving in gas, oil, water and other fluids with highly resistant to corrosion from moisture, chemicals and other harmful substances. Our products have many distinctive features as follows:
1.Excellent corrosion resistance: excellent resistance to acids and alkalis, and ensures longer service life under highly corrosive soil conditions;
2.Strong adhesion: primer and adhesive layer provide a strong adhesion under a wide range of service temperatures;
3.Easy repair: surface defects which may occur during transportation, storage of the pipes can be easily repaired;
4.Internal coating: excellent corrosion resistance and reduces the friction resistance of welded steel pipe in applications.