One type of pipe fitting is used for connecting pipes of two different diameters. According to their shapes, they are divided into concentric and eccentric reducers. The materials for reducers include stainless steel reducers (304, 304L, 316, 316L), alloy steel, carbon steel reducers, and the materials for reducers include 20# steel, Q235, Q345, 16Mn, etc. The main production area is in Mengcun Hui Autonomous County, Hebei Province. The manufacturing of reducers (eccentric pipe fittings): Reducers are pipe fittings used for different pipe diameters. The commonly used forming processes are reduced diameter extrusion, expanded diameter extrusion, or reduced diameter followed by expanded diameter extrusion. For certain specifications of eccentric pipes, stamping forming can also be used. 1. Reduced/Expanded Diameter Forming The reduced diameter forming process for reducers involves placing a tube blank with a diameter equal to the large end of the reducer into a forming mold, then through compression along the axial direction of the tube blank, the metal moves along the mold cavity and shrinks into shape. Depending on the size of the diameter change in the eccentric pipe, it can be formed in one or multiple steps. 2. Stamping Forming In addition to using steel pipes as raw materials to produce reducers, stamping forming processes can also be used to produce some specifications of reducers using steel plates. The shape of the stamping die used for stretching is designed according to the internal surface dimensions of the reducer, and the steel plate after blanking is stamped and stretched into shape using the die.