Lined pipes

The choice of lining material depends primarily on the chemical composition and temperature of the fluid. PTFE (Polytetrafluoroethylene) is the gold standard for universal chemical resistance and high temperatures (up to 260°C). PFA (Perfluoroalkoxy) is preferred for high-purity applications or vacuum conditions due to its superior melt-processability and bonding. For abrasive slurries, Rubber lining (Natural or Synthetic) or Ceramic lining is more cost-effective. Always verify the liner thickness (typically 3mm to 8mm) to ensure it meets the pressure rating of your system.

B2B buyers must ensure products comply with ASTM F1545, which is the standard specification for plastic-lined ferrous metal pipe and fittings. For the outer steel shell, ASTM A106 Grade B or API 5L are common. If the pipes are used in the food or pharma industry, FDA compliance for the liner is mandatory. For European markets, ensure the supplier provides CE marking and adheres to the Pressure Equipment Directive (PED 2014/68/EU).

You should request a Spark Test (Non-destructive) to detect pinholes or discontinuities in the liner; typically, a voltage of 10kV to 25kV is used depending on liner thickness. Additionally, perform a Hydrostatic Pressure Test at 1.5 times the design pressure. For vacuum applications, a Vacuum Resistance Test is critical to ensure the liner does not collapse or delaminate from the steel shell.

Lined pipes are sensitive to mechanical stress. Ensure the use of protective end caps during transit. During installation, do not weld near the lined sections as the heat will destroy the polymer liner. Use torque-limiting wrenches to avoid over-compressing the flared liner faces, which act as integrated gaskets. If gaskets are required, ensure they are compatible with both the fluid and the liner material.

The biggest risk is liner delamination or collapse during transit or early operation due to poor bonding processes. Another risk is dimensional inaccuracy in the 'Face-to-Face' length, which can stall onsite installation. To mitigate this, use Made-in-China.com's Secured Trading services and hire a third-party inspector (like SGS or BV) to verify dimensions and liner integrity before the balance payment is released.

Focus on the Total Cost of Ownership (TCO) rather than just the per-meter price. Negotiate for a warranty period of at least 18-24 months. Ask the supplier to provide Material Test Reports (MTRs) for both the steel and the resin. For large projects, request a staged payment plan (e.g., 30% deposit, 60% after inspection, 10% after successful installation/commissioning).

Lined pipes must be shipped with heavy-duty plastic or wooden end protectors to prevent the flared liner faces from scratching or cracking. For sea freight, ensure the pipes are internally dry and the steel exterior is coated with anti-rust varnish. Request seaworthy wooden crates for fittings and valves to prevent impact damage during container loading.

Be aware of Anti-Dumping Duties (ADD) on steel products which vary by country (e.g., US or EU duties on Chinese steel). Check the HS Code (typically 7304 or 7305) to determine the exact tariff rate. Utilize Made-in-China.com's logistics partners to navigate customs clearance and ensure all documentation, including the Certificate of Origin, is accurately prepared to benefit from any applicable trade agreements.