Introduction to Methods for Expanding the Diameter of Stainless Steel Seamless Pipes

This overview covers four methods for expanding the diameter of stainless steel seamless pipes: hot expansion, cold expansion, stretching, and pressure expansion. By analyzing these methods, this article aims to provide technical guidance to relevant industries.

1. Hot Expansion

  - Process: The pipe is heated, causing thermal expansion to increase the diameter, which is then maintained by mechanical equipment.

  - Procedure and Precautions: Includes heating, clamping, and cooling. Controlling temperature and time is crucial to avoid deformation or quality issues. Pipe walls must be protected against scratches and oxidation.

2. Cold Expansion

  - Process: Mechanical equipment is used to expand the diameter by squeezing the pipe, suitable for smaller diameters.

  - Control and Applications: Pressure and expansion must be controlled to prevent deformation or cracking. This method is widely used in electronics and instrumentation.

3. Stretching Expansion

  - Process: The pipe’s diameter is increased through mechanical stretching by controlling force and speed.

  - Advantages and Applications: Maintains the original material properties, ideal for larger diameter expansions. It’s simple, cost-effective, and used in shipbuilding, chemical, and construction industries.

4. Pressure Expansion

  - Process: External pressure is applied to plastically deform and expand the pipe's diameter.

  - Applications and Precautions: Suitable for small-diameter pipes with significant expansion potential. Pressure and speed must be controlled to prevent deformation or cracking.