Manufacturing Process of Ductile Iron Pipes

1. Raw Material Selection and Preparation

The process begins with the careful selection of high‑grade raw materials.

• Pig iron, scrap steel, and alloying elements are proportioned according to technical requirements.

• Each batch undergoes chemical composition analysis to ensure the proper carbon, silicon, and magnesium content essential for ductile iron production.

• Materials are pre‑treated to remove impurities and stored in a controlled environment to maintain quality.

2. Melting and Spheroidizing

The prepared charge materials are fed into medium‑frequency induction furnaces.

• The iron is melted at temperatures above 1,450 °C under strict supervision.

• Spheroidizing treatment is carried out by adding magnesium alloys or rare earth elements, which modify the graphite structure to form nodules.

• This step gives the iron its characteristic ductility and high tensile strength.

3. Centrifugal Casting

Luokaiwei utilizes advanced horizontal and vertical centrifugal casting machines:

• Molten ductile iron is poured into rapidly spinning molds, creating uniform pipe walls with fine‑grained structures.

• The centrifugal force ensures even distribution of material and eliminates internal porosity.

• Pipes are cast to meet AWWA C151, EN 545, and ISO 2531 standards, covering a wide range of diameters and pressure classes.

4. Annealing and Heat Treatment

After casting, pipes enter a controlled annealing furnace:

• The pipes are slowly heated and cooled to transform the iron matrix into a ferritic–pearlitic structure.

• This process enhances mechanical properties such as elongation, impact resistance, and toughness.

• Each batch is carefully monitored by digital sensors to guarantee uniform treatment.

5. Internal Lining

To protect against corrosion and improve hydraulic efficiency, every pipe is lined internally:

• تبطين الملاط الأسمنتي is applied via spinning machines to form a smooth, dense coating.

• For specialized applications, epoxy or polyurethane linings are available.

• Linings are tested for thickness, adhesion, and curing integrity before moving to the next stage.

6. External Coating

The exterior of the pipes is treated with multi‑layer protective coatings:

• A base layer of zinc spray أو zinc‑aluminum alloy is applied.

• Followed by a bituminous or epoxy finishing layer to resist soil corrosion and environmental factors.

• This coating system extends service life even in aggressive soil conditions.

7. Machining and Socket Finishing

Precision machining is performed on pipe ends:

• Bell and spigot ends are shaped to exact tolerances.

• Rubber gasket grooves are formed to ensure leak‑proof push‑on joints.

• Our CNC machines guarantee repeatability and compliance with dimensional standards.

8. Rigorous Quality Inspection

Every Luokaiwei ductile iron pipe undergoes comprehensive testing:

• Hydrostatic pressure tests ensure no leakage under rated pressures.

• Dimensional checks, ultrasonic testing, and metallographic inspection confirm structural integrity.

• Only pipes that meet or exceed the required specifications proceed to final packing.

9. Packing and Shipping

Once approved, pipes are carefully bundled and packed:

• Each pipe is marked with size, pressure class, standard, and batch number for traceability.

• Protective caps and end seals prevent damage during transit.

• Our global logistics network ensures timely delivery to ports and project sites worldwide.

لماذا تختار لوكايوي؟

✔ المعايير الدولية – We comply with AWWA, EN, ISO, and GB/T specifications.
✔ التكنولوجيا المتقدمة – Automated casting and coating lines ensure high productivity.
✔ Custom Solutions – Linings, coatings, and sizes tailored to project requirements.
✔ الوصول العالمي – Trusted by infrastructure projects across Asia, Europe, the Middle East, Africa, and the Americas.