Forging ratio is a key step in forging process, which should be taken into consideration such factors as metal material type, forging performance requirement, process type and shape size of forgings.
The casting defects of alloy structural steel ingot are more serious than those of carbon structural steel ingot, the required forging ratio is bigger.
The quality of electroslag steel is better than that of general smelting steel, the required forging ratio is smaller.
In order to weld the internal defects of the forgings, the optimum mechanical performance index is obtained vertically, and the minimum forging ratio must be satisfied with the different ingot specifications: 1t ingot is 2.5, 3t ingot is 2.7, 5t ingot is 2.8, 10t ingot is 3, and 30t ingot is 4.
When the forging force direction is inconsistent with the fiber direction, in order to ensure the transverse performance and avoid the obvious anisotropy, the forging ratio is 2.0 ~ 2.5, and when the forging force direction is basically the same as the fiber direction, the forging ratio is preferable to 2.5 ~ 3.0; When the forging force direction is exactly the same as the fiber direction (for example, the hydraulic press column), In order to improve the longitudinal performance, it is preferable to forge 4 or higher.
High-stress shaft forgings (such as turbine shafts, rotor shafts, etc.) for high-speed rotation and transmission torque in the aeronautical industry are more suitable than those for $number, and the best materials are used for rolling. When the large-scale important forgings not only require a larger forging ratio, but also do not allow the performance of the opposite sex too large, can increase the middle upsetting process, the use of repeated upsetting rough drawing of the combination process.
For the smaller forgings made of bar (except for Laigang), because of the great deformation degree of the bar which has been forged or extruded, the microstructure and performance are improved greatly, so only the deformation requirement between the processes is considered, and the general forging ratio is no longer considered.
The forging of a ferrous alloy tool steel ingot used as a mold must generally have upsetting processes. The degree of upsetting deformation should not be less than 50%. The minimum forging ratio of the module shall be 3. The tendency of forming a mesh carbide is generally used as a tool steel for the cross alloying of the die. In order to ensure that the mesh carbide is fully broken, the forging ratio should be equal to or greater than 10 in addition to the correct control of the forging temperature.