Buckling pipe expander

The utility model relates to a withholding pipe expander, which belongs to the technical field of withholding pipe expanders and comprises a circular withholding cover plate fixedly mounted on a fixed table, a plurality of withholding inserts which are detachably connected and a plurality of movably connected pipe expanding inserts are sequentially arranged in the withholding cover plate, and movably connected mandrels are arranged in the pipe expanding inserts. The lower end of the mandrel is provided with a cylinder or motor. The pipe expanding machine is buckled and pressed to replace a traditional stamping mode, the pipe expanding work of the pipeline can be directly and automatically achieved, the working efficiency is high, the practicability and the adaptability are good, the radian of the bent pipeline can be treated, and operation is easy, fast and convenient; the pipe expanding work can be performed on pipelines with different pipe diameters through the replacement of the detachably ...