Elbows (reducing fittings) are pipe fittings used for changing pipe diameters. Common forming processes include necking down, expanding, or a combination of both necking and expanding. For certain sizes of reducing elbows, stamping forming can also be employed.

Contraction/Expansion Forming

The reduction forming process for reducing elbows involves placing a billet with the same diameter as the large end of the reducing elbow into a forming die. Through compression along the axial direction of the billet, the metal moves and shrinks into shape within the die cavity. Depending on the size of the diameter change of the reducing pipe, it is classified into single-stage or multi-stage forming.

b. Stamping成形

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