Reduced or eccentric pipes are fittings used for varying pipe diameters. The commonly used forming processes include reducing and expanding, expanding only, or a combination of both reducing and expanding. For certain specifications of eccentric pipes, stamping forming can also be employed.

Contraction/Expansion Forming

The reduction forming process for reducing elbows involves placing a tube blank with a diameter equal to the large end of the reducing elbow into a forming mold, and then, through pressing along the axial direction of the tube blank, the metal moves within the mold cavity and forms by shrinking. Depending on the size of the diameter change of the reducing pipe, it is divided into single forming or multiple forming.

b. Press forming

In addition to producing elbows using steel pipes as raw material, elbows of certain specifications can also be manufactured using steel plates via the stamping forming process. The shape of the stamping die used for stretching is designed based on the inner surface dimensions of the elbows, and the steel plate after cutting is stamped and stretched into shape using the die.