The microstructure and mechanical properties of large forgings are related to many factors, and the forging ratio is one of the most important factors affecting the quality of forgings.
Forging ratio is a way of expressing the degree of metal deformation during forging. The higher the forging ratio is, the higher the deformation degree of the forgings will be. The deformation degree is directly related to the final inclusion size, the crushing degree of the eutectic carbide, the fiber flow direction and density after the final forming of the materials, and has a great influence on the comprehensive properties of the materials.
The distribution of forging ratio (i.e. deformation degree) in forgings with different forging ratios is not uniform, which is obviously divided into large forging ratio region, average forging ratio region and small forging ratio region. The MECHANICAL PROPERTIES EXPERIMENTS SHOW THAT THE STRENGTH INDEX AND PLASTICITY index OF rolled steel can be improved obviously by plastic deformation with a certain forging ratio under the same heat treatment conditions. When the forging ratio reaches a certain value, the microstructure and properties of large forging change fiercely, and its strength increases to the best, but its toughness decreases obviously. At the same strain rate, the larger the forging ratio (i.e. the degree of plastic deformation), the more obvious the dynamic recrystallization in the forging structure. When the forging ratio reaches a certain value, the original grain will be replaced by the new recrystallized grain, and relatively complete dynamic recrystallization will occur.
At present, there are three kinds of technological schemes to improve the uniformity of forging ratio, which are changing the boundary conditions between blank and die, changing the shape of blank, and changing the upsetting deformation mode. The forging ratio and geometric size uniformity of forgings can be improved effectively by changing the upsetting deformation mode of flat anvil. Therefore, to improve the forging ratio of large forgings, in order to better improve the quality of ring forgings.
this is foging production line of tongxin precision forging company