Common materials for reducers include stainless steel, carbon steel, and alloy steel. Stainless steel materials include 304, 304L, 316, and 316L. Carbon steel materials include 20# steel, Q235, and Q345. In addition, depending on specific requirements, American standard stainless steel materials such as ASTM A403 WP304/304L/304H, 316/316L, 310S, and duplex stainless steel S32205 are also used.
The production and quality of reducers must comply with a series of national, international, and industry standards. Core standards include the national standards GB/T 12459-2005 "Seamless Butt-Welded Pipe Fittings" and GB/T13401-2005 "Butt-Welded Pipe Fittings from Steel Plates." American standards include ASTM A106/A53 GRB, ASTM A105, ASTM A234, ASTM A106, and ANSI/ASME B16.9. Other common standards include SY/T5037, GB/T9711, GB/T8163, API 5L, and DIN German standards. [2-4] In addition, there are corresponding ministerial standards for different industrial sectors, such as the Ministry of Electric Power standards GD0506~0507, the Ministry of Machinery standards JB/T81-59/JB/T74-94, the Ministry of Petrochemical Industry standards SH3406-96, and the Ministry of Chemical Industry standards HG5010-58/HG20592-97.
The forming processes commonly used for reducers are diameter reduction pressing, diameter expansion pressing, or diameter reduction plus diameter expansion pressing. For certain specifications of reducers, stamping can also be used. The diameter reduction forming process involves placing a tube blank with the same diameter as the large end of the reducer into a forming mold. Through pressing along the axial direction of the tube blank, the metal moves along the mold cavity and shrinks to form the shape. Depending on the size of the diameter change, it can be formed by one or multiple pressing operations. Expanding forming involves using a tube blank smaller than the diameter of the larger end of the reducer, and expanding it along the inner diameter of the tube blank using an internal die. This method is mainly used when the diameter change is too large. During the shrinking or expanding deformation pressing process, the choice between cold pressing or hot pressing is determined based on the different materials and diameter change conditions.
