Production Process of Seamless Steel Pipes
Seamless steel pipes are manufactured through a series of precise steps to ensure high strength and durability. The key production stages include:
1. Billet Preparation: High-quality cylindrical steel billets are heated to extremely high temperatures (around 1,200°C) to make them malleable.
2. Piercing: A rotary piercing mill uses a mandrel to create a hollow shell by piercing the center of the heated billet, forming a rough tubular shape.
3. Elongation: The hollow shell is rolled and stretched using a mandrel mill or plug mill to achieve the desired wall thickness and diameter.
4. Sizing: The pipe passes through sizing mills to refine its dimensions and ensure uniformity.
5. Cooling & Straightening: The pipe is cooled in a controlled environment, then straightened using hydraulic or mechanical methods.
6. Cutting & Inspection: The finished pipes are cut to specified lengths and undergo rigorous testing (e.g., ultrasonic, hydrostatic) to verify quality.
Common production methods include hot rolling (for thicker pipes) and cold drawing (for precise dimensions and smoother surfaces).
