Reducing pipe (size head) is a pipe fitting used for reducing the diameter of a pipe. The commonly used forming process is reducing pressing, expanding pressing or reducing plus expanding pressing, and stamping can also be used for some specifications of reducing tubes.
Reducing/expanding forming
The reducing forming process of reducing tube is to put the tube blank with the same diameter as the big end of the reducing tube into the forming die. By pressing the tube blank along the axial direction, the metal moves along the die cavity and shrinks into shape. According to the size of the reducing tube, it can be divided into one pressing forming or multiple pressing forming.
Expanding forming is to use the tube blank less than the big end diameter of the reducing tube, using an internal die along the tube blank inner diameter expanding forming. The expanding process mainly solves the problem that the reducing tube with larger diameter is not easy to be formed by reducing diameter. Sometimes, according to the forming needs of materials and products, the method of expanding and reducing diameter is combined.
In the process of reducing or expanding deformation pressing, according to different materials and reducing conditions, determine the use of cold pressing or hot pressing. Under normal circumstances, cold pressing is used as far as possible, but hot pressing is appropriate for the case of serious work hardening caused by multiple diameter reduction, the case of thicker wall or alloy steel materials.
Stamping forming
In addition to using steel pipe as raw material to produce reducing pipe, some specifications of reducing pipe can also be produced by stamping steel plate. The shape of the die used for drawing is designed according to the size of the reduced inner surface, and the steel plate after blanking is pressed and drawn by the die.
