Cangzhou Avant International Trade Co., Ltd. is one of the leading manufacturers and suppliers of internally and externally coated steel pipe in China. We are committed to providing high quality customized products with competitive price. Welcome to wholesale cheap internally and externally coated steel pipe in stock here from our factory. Also, free sample is available.
The core value of the internal and external plastic-coated steel pipe lies in its "double protection" mechanism. By melt-coating polymer materials such as epoxy resin (EP) or polyethylene (PE) on the inner and outer walls of the steel pipe, a tight molecular-level bond is formed between the coating and the matrix. This combination not only blocks the direct contact between corrosive media such as water, oxygen, acid, alkali and salts and steel pipes, but also fundamentally eliminates the problems of easy scaling and bacterial growth on the inner walls of traditional pipes.
In actual working conditions, this structure brings significant performance improvements. The smoothness of the inner wall greatly reduces fluid friction resistance, which not only improves the transportation efficiency, but also effectively reduces the operating energy consumption of the pump station. At the same time, whether facing soil stress in the buried environment or high-pressure impact during transportation, the steel pipe matrix can still provide solid mechanical support to ensure the structural integrity of the pipeline system in complex environments.
The technical requirements for inner wall coatings vary depending on the transport medium, and can be mainly divided into the following three categories:
Drinking water and domestic water. In addition to hygienic safety, the surface roughness (Ra) of the inner wall coating is a key parameter affecting the hydraulic performance. After the high-quality inner coating is cured and polished, the surface roughness can be controlled below 10 μm, which is close to the level of hydraulically smooth pipes, helping to reduce pumping energy consumption. AWWA C210 and ISO 15741 have clear regulations on the adhesion, bending performance, cathodic peeling resistance and immersion test of the liquid epoxy coating on the inner wall of drinking water pipes.
Industrial media (seawater, acid-base solutions, high-temperature hot water). Under such working conditions, the temperature resistance and chemical resistance of ordinary bisphenol A epoxy resin may be insufficient. Phenolic epoxy coatings are more stable in hot water, salt spray and weak acid and alkali environments of 80-120°C, but their construction windows are narrow and the requirements for surface pretreatment and curing conditions are more stringent. The selection should be based on the media composition analysis report, and if necessary, entrust the coating supplier to conduct chemical compatibility testing.
Drag reducing inner coating (FBE lining). In long-distance oil and gas pipelines, the main function of the inner wall FBE coating is to reduce the friction coefficient of the fluid in the pipe and improve the transportation efficiency. API RP 5L7 and NACE SP0394 provide detailed regulations on the technical requirements, construction technology and inspection methods of this type of coating. It should be pointed out that the drag-reducing inner coating is not the primary purpose of anti-corrosion and should not be used as the only means of internal protection in corrosive media environments.
During the production process, the inner and outer wall coatings are applied separately, and each coating must be fully cured before entering the next process to avoid blistering and pinhole defects caused by the coating not drying. The finished product will be tested for coating thickness and adhesion on the inner and outer walls respectively. At the same time, electric spark leakage detection will be performed to check for leakage and pinhole hazards, so as to intercept quality problems before leaving the factory. If customers have special requirements, the coating thickness can also be adjusted to adapt to higher standard project designs.
We have mature foreign trade processing and shipping processes, and we can arrange production whether it is a large-volume engineering order or a small-volume trial order. All products can provide a complete set of documents such as material sheets, anti-corrosion process records, and test reports to meet the data requirements for overseas third-party inspection, bidding, and project filing.
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