Manufacture of carbon steel reducer

　　The roundness of carbon steel reducer shall not be greater than 1% of the corresponding end outer diameter, and the allowable deviation is ± 3mm. The material of reducer shall comply with SY / t5037, GB / t9711, GB / t8163, American Standard ASTM A106 / A53 GRB, API 5L, apt5ct, ASTM A105, ASTM a234, ASTM A106, DIN German standards and customer requirements

　　Reducer (reducer) is a kind of pipe fitting used for reducing pipe diameter. The commonly used forming processes are reducing pressing, expanding pressing or reducing plus expanding pressing. For some sizes of reducers, stamping can also be used.

　　a. Reducing / expanding forming

　　The reducing forming process of reducing pipe is to put the tube blank with the same diameter as the big end of reducing pipe into the forming die. By pressing along the axial direction of the tube blank, the metal moves along the die cavity and shrinks to form. According to the size of reducer, it can be divided into one-time pressing forming or multiple pressing forming.

　　Expanding forming is to use the tube blank which is smaller than the diameter of the big end of the reducing tube to expand along the inner diameter of the tube blank with an internal die. The expanding process is mainly used to solve the problem that the reducer with large diameter is not easy to be formed by reducing. Sometimes, expanding and reducing methods are combined according to the needs of material and product forming.

　　In the process of reducing or expanding, cold pressing or hot pressing is determined according to different materials and reducing conditions. In general, cold pressing should be used as much as possible, but hot pressing should be used in case of severe work hardening caused by multiple diameter changes, thick wall or alloy steel materials.

　　b. Stamping forming

　　In addition to using steel pipe as raw material to produce reducers, some reducers can also be produced by stamping process with steel plate. The shape of the die used for drawing is designed according to the size of the inner surface of the reducer, and the blanking steel plate is formed by stamping and drawing with the die.