What Are The Distribution Rules Of Forging Deformation?

The internal deformation distribution of cake, cylinder and shaft forgings is systematically studied by physical simulation method. It is found that due to the boundary friction, there is no obvious transition zone between the large deformation zone and the rigid zone during the deformation process, and a severe shear deformation zone is formed between the two zones. With the increase of deformation, the stress inside the material will change after the deformation zone is greatly deformed. When the deformation continues to increase, the shear zone begins to move and causes the rigid zone to enter the plastic state layer by layer.

Under the above conditions, coupled with the presence of inclusions and coarse grain boundaries, cracks are very easy to occur at the inclusions and grain boundaries. For example, during the upsetting process, the deformation is very severe in the shear zone between the rigid zone in contact with the anvil and the large deformation zone in the middle part. When the deformation reaches a certain value, the original rigid zone begins to deform, resulting in a sharp increase in load, which often leads to defect expansion. Similar phenomena also exist in the deformation process of module, cylinder and shaft forgings.

Moire method was used to study the microscopic deformation distribution of defects such as inclusions and voidings. It was proved that the morphology of defects directly affects the degree of stress concentration. The combined action of shear deformation and local stress of defects resulted in the fracture of metal matrix between defects, and the tiny inclusions were connected through cracks and then extruded into cracks. Until the formation of larger inclusion cracks is one of the important reasons for excessive detection. It can be used to explain the causes of the defects in the center clamping layer of the cake forging, and to lay a theoretical foundation for eliminating such defects.

The appearance of inclusions and grain boundary condition directly affect the performance of large forgings, and the unreasonable defect distribution may become a major hidden danger of sudden failure of large forgings during use. Although the current inspection standards can not be scientifically judged, but in the forging process should make full use of deformation characteristics to ensure the reasonable distribution of defects. Studying the deformation distribution law can effectively solve the problem of cavity compaction, and provide technological parameters for deformation control of grain size and even production of complex forgings.