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The epoxy coal-tar coating steel water pipe is a carbon steel welded or seamless pipe commonly used in water supply systems, where the base steel pipe has been protected with an epoxy coal-tar coating. These steel water pipes are widely used for water transmission and water distribution.
This coating primarily consists of epoxy resin and coal tar as the main film-forming substances, with various rust-inhibiting pigments, insulating fillers, toughening agents, and other additives. The paint can be viewed as an epoxy modified with coal tar and other additives. Its characteristics include excellent adhesion, toughness, resistance to moisture, water, and acids, alkalis, saltwater, volatile oils, salt spray, and other chemical substances, as well as the ability to expand and contract in sync with the substrate, ensuring the coating does not peel off or crack. Especially, the epoxy coal-tar coating is known for its excellent water resistance and ability to form a dense, impermeable barrier, making it suitable for underwater piping systems and underground water pipes.
The base pipes furnished with the epoxy coal-tar coating are typically steel water pipes manufactured in accordance with AWWA C200 standard specifications. It can be either a carbon steel seamless pipe, longitudinally electric-resistance-welded (ERW) pipe, or spirally submerged-arc-welding (SSAW) pipe. These steel water pipes usually have an outer diameter ranging from 100 mm to 4000 mm, a wall thickness from 5 mm to 16 mm, and pressure ratings ranging from PN6 to PN40. The steel grades include ASTM A283, ASTM A516, ASTM A36, ASTM A515, etc.
The application of epoxy coal-tar coating to AWWA C200 steel water pipes involves several steps to ensure proper adhesion and corrosion protection. Generally, it shall be furnished in accordance with AWWA C210 standards. Here’s an overview of the production process: