What are the differences between cold forging and hot forging of flange plates

The cold forging of flanges is done at low temperatures, where the size of the flange changes very little. Forging below 700 ℃ results in less oxide skin formation and no decarburization on the surface. Therefore, as long as the deformation energy is within the range of forming energy, cold forging can easily achieve good dimensional accuracy and surface finish. As long as the temperature and lubrication cooling are well controlled, warm forging below 700 ℃ can also achieve good accuracy. A general term for plastic processing such as cold forging, cold extrusion, and cold heading. Cold forging is the forming process of materials below the recrystallization temperature, which is carried out below the recovery temperature. Forging without heating the blank is commonly referred to as cold forging in production. Cold forging materials are mostly aluminum and some alloys, copper and some alloys, low carbon steel, medium carbon steel, and low alloy structural steel with low deformation resistance and good plasticity at room temperature. Cold forging has good surface quality and high dimensional accuracy, which can replace some cutting processes. Cold forging can strengthen the metal and improve the strength of the flange.

The development of cold forging technology mainly involves developing high value-added products and reducing production costs. At the same time, it is constantly infiltrating or replacing cutting, powder metallurgy, casting, hot forging, sheet metal forming processes and other fields, and can also be combined with these processes to form composite processes.

The hot forging of flanges is: during hot forging, large flanges with complex shapes can be forged due to their low deformation energy and resistance. To obtain high-precision flanges, hot forging can be used within the temperature range of 900-1000 ℃. In addition, attention should be paid to improving the working environment for hot forging. The service life of the forging die (hot forging of 2-5000 pieces, warm forging of 1-20000 pieces, and cold forging of 20-50000 pieces) is shorter compared to forging in other temperature domains, but it has greater freedom and lower cost. The main purpose of hot forging flanges is to reduce the deformation resistance of the metal, thereby reducing the forging pressure required for deformation of damaged materials and greatly reducing the tonnage of forging equipment; Change the as-cast structure of the flange material steel ingot, and after recrystallization during the hot forging process, the coarse as-cast structure becomes a new structure with fine grains, reducing defects in the as-cast structure and improving the mechanical properties of the steel;