1. Forging method: The end or part of the pipe is extruded with a forging machine to reduce the outer diameter. Common forging machines are rotary, link, roller.

2. Stamping method: Use a tapered core to expand the pipe end to the required size and shape on the punch.

3. Roller method: The core is placed in the tube, and the periphery is pressed by rollers for round edge processing.

4. Rolling method: Generally, no mandrel is used, which is suitable for the inner round edge of thick-walled pipes.

5. Bending forming method: There are three methods more commonly used, one method is called the stretching method, the other method is called stamping method, and the third roller method has 3-4 rollers, two fixed rollers, one adjustment roller, adjustment With fixed roller pitch, the finished pipe is bent.

6. Bulging method: one is to place rubber in the tube and compress it with a punch above to make the tube protrude and form; the other method is to use hydraulic inflation to form a liquid in the middle of the tube. The liquid pressure swells the tube into the required one. This method is mostly used in the production of shapes and bellows.