How Is Seamless Stainless Steel Pipe Made?

Would you like to know how seamless stainless steel pipes are made? Union Steel provides a brief introduction to the manufacturing process of these pipes.
There are four main production methods for stainless steel seamless pipes: hot rolling, cold rolling, cold drawing, and extrusion.

Manufacturing Process Of  Stainless Steel Seamless Pipe

1. Hot Rolling:

Hot-rolled seamless stainless steel pipes are typically produced using automatic pipe rolling mills. The solid pipes are inspected first, and any surface defects are removed. They are then cut to the required length and centered on the pierced end of the pipe. The pipe is then sent to a heating furnace and punched on a punching machine. The inside of the tube gradually forms a cavity under the action of the roller and plug.

The process for creating a pipe from a round tube blank involves heating, piercing, and then either three roll cross rolling, continuous rolling, or extrusion. The pipe is then stripped, sized or reduced, cooled, straightened, and subjected to a hydrostatic test or flaw detection. Finally, it is marked and stored in a warehouse.

2. Cold Rolling / Drawing:

For the manufacture of smaller and higher quality stainless steel seamless pipes, it is recommended to use a combination of cold rolling and cold drawing processes.

The manufacturing process involves the following steps: round pipe blank → heating → piercing → heading → annealing → pickling → oiling (copper plating) → multi-pass cold drawing (cold rolling) → blank pipe → heat treatment → straightening → hydrostatic test (flaw detection) → marking → warehousing.

3. Extrusion:

Extrusion is a common technique used to produce smooth stainless steel pipes, and is the only suitable method for creating long-lasting, smooth stainless steel coil tubing. The extrusion process can produce pipes with the most standardized outer diameter and the most precise inner diameter. During the process, a heated tube blank is placed in a closed extrusion cylinder, and the perforated rod and extrusion rod move together to extrude the material through a smaller die hole.