Cold Drawn Double-Layer Stainless Steel Pipe

1. Product Description
This cold drawn double-layer stainless steel pipe is a composite pipe consisting of two concentric stainless steel layers (inner and outer) that are tightly bonded through a cold drawing process. The inner layer provides corrosion resistance to the conveyed medium, while the outer layer offers structural strength and additional protection. The cold drawing process ensures precise dimensions, a smooth surface finish, and high bonding integrity between the layers. Available with different material combinations (e.g., 304 inner / 201 outer, or 316L inner / 304 outer) to suit specific application requirements.

2. Key Specifications

• Construction: Double-layer (inner + outer) stainless steel, metallurgically or mechanically bonded via cold drawing

• Material Combinations: 304/304, 316L/304, 304/201, or customized

• Outer Diameter: 6mm – 630mm (customizable)

• Wall Thickness: 0.5mm – 30mm (total)

• Length: 5.8m / 6m fixed, or custom cut

• Surface Finish: Annealed, pickled, polished, or bright annealed

• Standards: ASTM A269/A213/A312, EN 10216-5, GB/T 14976

• Testing: Hydrostatic test, eddy current test, tensile test, flattening test

3. Applications
Suitable for pipeline systems requiring combined corrosion resistance and structural strength, including: chemical processing (corrosive fluid transport), food and beverage industry (hygienic piping), water treatment, marine and offshore environments, instrumentation lines, heat exchangers, and decorative/structural applications where both aesthetics and durability are required.

4. Product Advantages

• Cold drawing process produces precise dimensions and excellent surface finish

• Tight interfacial bonding between layers prevents delamination under normal operating conditions

• Inner layer provides corrosion resistance while outer layer contributes mechanical strength

• Cost-effective compared to solid stainless steel pipe of equivalent corrosion performance

• Smooth inner bore minimizes flow resistance and prevents scaling

• Available in customized material combinations for specific corrosion/strength requirements

5. Product Functions
The double-layer pipe conveys fluids while protecting against corrosion on the inner surface and providing structural integrity through the outer layer. The cold drawn construction ensures dimensional accuracy for precision fitting and welding. It serves as a reliable conduit in systems where both media compatibility and mechanical durability are essential.

6. Instruction for Use

• Verify pipe grade, dimensions, and layer configuration match the system design.

• Inspect pipe ends for damage or layer separation before installation.

• Clean pipe ends and remove any protective caps or coatings prior to welding or fitting.

• For butt welding: align pipes carefully, use appropriate filler metal (ER308L for 304, ER316L for 316L), and follow qualified WPS.

• Avoid excessive heat input that may affect the bond between layers.

• Perform pressure testing after installation to confirm joint integrity.

7. Precautions

• Do not subject the pipe to severe impact or bending that may cause layer separation.

• Store in a dry, covered area; keep away from carbon steel contact to prevent galvanic corrosion.

• Do not use damaged or delaminated pipe sections.

• Verify that the material certificate includes layer configuration and test results.

• For welded connections, ensure the weld procedure is qualified for double-layer construction.

• Avoid using the pipe outside its specified temperature and pressure ratings.

8. Shipping Information

• Standard export packing: wooden case or steel frame, with plastic end caps and anti-corrosion wrapping.

• Dispatch within 15–30 days depending on order quantity and customization.

• Shipping methods: sea freight, air freight, or express courier.

• Tracking number and packing list provided upon dispatch.

9. Payment Terms

• T/T: 30% deposit, 70% balance before shipment.

• L/C at sight accepted for larger orders.

• PayPal / Western Union for sample orders.

• Prices quoted EXW or FOB unless otherwise specified.

10. Packaging

• Each pipe end protected with plastic cap.

• Pipes bundled with anti-rust strip or wrapped in plastic film.

• Packed in wooden cases or steel frames for export.

• Desiccant added for sea shipments.

• Custom marking (size, grade, heat number) available upon request.

11. Return & After-Sales Policy

• 7-day return or exchange for verified quality defects (layer separation, dimensional non-conformance).

• Custom-cut or custom-manufactured items are non-returnable unless defective.

• Warranty: 12 months from delivery for manufacturing defects.

• Claims for damage or shortage must be reported within 3 working days of receipt with photo evidence.

• Technical support available for welding procedures and material selection