Selecting the base pipe is the first step. Spiral-submerged-arc-welded (SSAW) pipes are the most widely supplied; they are well-suited for large-diameter, low-pressure water transport and sewage projects, offering better cost control. Longitudinal-submerged-arc-welded (LSAW) pipes, which feature fewer weld seams and superior stability, are the preferred choice for high-pressure gas transmission, chemical transport, and deep-sea infrastructure. Seamless steel pipes are used only in rare, specialized, high-pressure, or small-batch applications. These pipes cover a broad range of diameters-typically starting from DN200 and extending to DN3000 or larger-and are generally supplied in standard lengths of 6 or 12 meters, though they can also be cut to specific project requirements.
The coating specification is the core of the selection process. Since different coatings are designed for different operating environments, this is a critical detail that overseas engineers frequently prioritize for verification. The 3PE (three-layer polyethylene) coating is the most prevalent standard for buried oil, gas, and utility pipelines internationally. It consists of a fusion-bonded epoxy (FBE) primer, an adhesive middle layer, and a polyethylene top layer. This system offers excellent resistance to soil corrosion and water penetration, combined with high toughness and impact resistance; it is widely recognized under Western standards such as DIN 30670 and AWWA C210. FBE (fusion-bonded epoxy) coatings, meanwhile, provide superior adhesion, higher temperature resistance, and excellent chemical resistance against acids and alkalis-making them the preferred choice for handling chemical wastewater, high-temperature circulating water, or for use in highly corrosive soils, such as those found in mining areas. Additionally, internal and external epoxy (EP) coatings are frequently used; the smooth internal surface minimizes fluid resistance and prevents the accumulation of impurities, making them ideal for transporting potable water or municipal clean water. Cement mortar linings are typically applied only to the interior of water pipelines, paired with an external PE anti-corrosion coating. Many projects utilize hybrid solutions-such as an external 3PE coating combined with an internal epoxy lining-to ensure both robust external protection against soil corrosion and internal cleanliness for the transported medium.
The choice of connection method depends on pipe diameter and operating pressure. For small to medium-diameter pipes, grooved couplings or flanged connections are common, while large-diameter pipes (DN600 and above) are generally joined via butt-welding. A critical detail here is that the welding process damages the coating at the joint; therefore, we provide specialized field-joint coating materials-such as heat-shrinkable sleeves or repair-grade epoxy powder-to restore protection. Without this, the weld zone would become the weakest point, susceptible to premature corrosion and failure.
These products have a broad range of applications, including municipal water mains, separate sewer and stormwater systems, and seawater desalination pipelines. They are also used for long-distance oil and natural gas transmission and distribution lines, circulating water systems in power plants, and the transport of chemical wastewater. Furthermore, they are employed in structural applications such as pile foundations, port infrastructure, and protective casings for offshore engineering. Many of our international EPC (engineering, procurement, and construction) clients opt to source a complete package-including flanges, insulated pipe supports, and hangers-consolidated into containers for shipment, which streamlines the procurement process by reducing the need to coordinate with multiple suppliers. Regarding production standards, we adhere to domestic standards such as GB/T 23257 and CJ/T 120. For export orders, we comply with international specifications including API 5L, AWWA, DIN, and EN, and can provide CE certification as well as third-party inspection reports from SGS or BV. Every pipe undergoes hydrostatic testing, holiday detection (to identify pinholes in the coating), and adhesion testing before leaving the factory to ensure there are no defects or damage to the coating. Coating thickness and holiday detection voltage can be adjusted according to the technical requirements of your specific project.
We take extra care with transport and packaging; any scratch on the coating could lead to corrosion once the pipe is buried. We avoid using standard steel wire ropes for lifting, opting instead for nylon slings. We also place wooden blocks and rubber spacers between the pipes to prevent impacts or abrasions to the coating. For large-volume shipments, we offer options for bulk vessel transport or containerized packing. Additionally, we fit plastic end caps to the pipe openings to prevent dirt, debris, or foreign objects from entering.
If you are a pipeline trader, an overseas EPC contractor, or a procurement representative for water, oil, or gas projects, simply provide us with the base pipe type, outer diameter and wall thickness, coating specifications, the medium to be transported, design pressure and temperature, and the relevant standards for your target market. We will then calculate a quotation and determine the production lead time. We handle everything from prototype production to large-scale orders, with customizable options for pipe-end beveling, field-joint coating materials, and product marking. Please feel free to send us your drawings or technical specifications so we can discuss your requirements further.
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