In conventional pipe manufacturing, steel sheets are prepared according to the final pipe wall thickness, then rolled into the desired diameter and welded. For example, to produce a 88.9×3.0 mm black pipe, a 3.0 mm steel sheet is sliced to 280 mm width (88.9×3.14), rolled, and welded into a pipe. This method causes:
- Inner weld protrusion (internal burr)
- Hardening of the steel during rolling
- Uneven mechanical properties in the pipe
SRM technology overcomes these disadvantages. In SRM production:
- The pipe is initially produced at the largest possible diameter.
- The internal burr is removed during welding.
- The pipe is heated up to 900°C in a closed-system roller line.
- It is then drawn to the final diameter and wall thickness, achieving a completely homogeneous structure with all internal stresses removed.
An SRM pipe entering the line at 90 mm diameter can be reduced to 21 mm, fully stress-relieved and softened.
Advantages of SRM Pipes
- Easily formable: Annealed pipes are highly suitable for bending.
- Seamless weld line: Weld seams disappear after drawing, preventing cracks or folding in tight bends.
- Smooth inner surface: Prevents scale accumulation.
- High corrosion resistance: Long service life.
- Small diameter, thick-walled pipes: Achievable where conventional welded pipes cannot, making SRM pipes competitive with seamless pipes.
- Cost-effective: SRM pipes are much cheaper than seamless pipes.
Applications of SRM Pipes
- Natural gas pipelines
- Boiler tubes
- Heat exchanger pipes
- Coil (serpentine) pipes
- General piping systems
- Couplings
- Elbows
- Automotive pipes
