Notes of Seamless Steel Pipe Manufacturing Process

1. Pigging: The steel billet, typically a round ingot, is cleaned and inserted into a mandrel to facilitate the piercing process. This is known as pigging and is done to ensure the billet is centered and to remove any scale or contaminants.

2. Piercing: The billet is pierced by a spinning mandrel, which creates a hole in the center of the billet. This hole will become the internal diameter of the pipe. The mandrel is typically driven by a motor and may be assisted by a die to achieve the desired pipe diameter.

3. Hot Rolling: The pierced billet is then subjected to hot rolling, where it is passed through a series of rollers at high temperatures. This process stretches the metal and increases its diameter to the desired pipe size. The rolling process may be done in multiple steps to achieve the final wall thickness.

4. Cooling: After hot rolling, the pipe is cooled down to room temperature. This can be done in water or air, depending on the material and requirements of the pipe.

5. Sizing: The pipe may undergo a sizing process to achieve a more precise internal diameter and wall thickness. This can be done using internal expanders or by passing the pipe through dies that slightly compress the pipe walls.

6. Heat Treatment: Depending on the material and the desired properties of the pipe, it may undergo heat treatment processes such as annealing or tempering. These processes help improve the pipe's mechanical properties, such as strength and toughness.

7. Straightening: The newly manufactured pipe may contain slight curvatures or twists. It is important to straighten the pipe to ensure dimensional accuracy and ease of handling.

8. Ultrasonic Testing: To ensure the integrity of the pipe, ultrasonic testing may be performed to detect any internal or external defects. This non-destructive testing method is crucial for quality control.

9. Mechanical Testing: The pipe is subjected to mechanical tests, such as tensile, bend, and impact tests, to verify its strength and durability.

10. Surface Treatment: The surface of the pipe may be treated to enhance its corrosion resistance or to achieve a specific finish. This can include processes like galvanizing, painting, or polishing.

11. Cutting to Length: The pipe is cut to the required length, either manually or using automated cutting machines, to meet specific project specifications.

12. Inspection and Packaging: The final product is thoroughly inspected for dimensional accuracy, surface finish, and overall quality. Once passed, the pipes are packaged securely for storage and transportation.