1. Stamping method: In the punching machine with taper of the core to extend the pipe end to the required size and shape.
2. Bending forming method: There are three methods are more commonly used, one method is called stretching method, another method is called stamping method, the third roller method, there are 3-4 rollers, two fixed rollers, one adjustment roller, adjust the fixed roller spacing, finished pipe fittings is curved.
3. Bulging method: A rubber is placed in the tube, the top with a punch compression, so that the pipe bulge forming; Another method is hydraulic bulging forming, filled with liquid in the middle of the pipe, the pressure of the pipe to drum into the shape required, the production of corrugated pipe is mostly used in this way.
4. Forging method: The use of forging machine will be beveling part or part of the extension, so that the outer diameter of the tube is reduced, common type forging machine has rotary, connecting rod type, roller type.
5. Rolling method: Generally without mandrel, suitable for thick wall tube inside round edge.