Deformation Modes And Flow Behavior Of Metal In Die Forging Process Of Disk Components

From the view of plastic mechanics, the deformation of closed-die forging can be divided into three basic deformation modes: cylindrical billet compression, ring compression and pseudo-extrusion. It makes the analysis modularizetion. Analyzing different deformation mode and coupled flowing behaviors, the rule of metal flowing was disclosed for complex components, which supplied with theoretical references for the investigation on the plastic forming of complicated forgings.The deformation characteristics of closed-die forging were analyzed deeply, which were the theoretical basis of three deformation modes for closed-die forging. Based on the Lode parameter, a new research method is proposed to study the different deformation zones for closed-die forging. The quantitative relation between stress field and strain increment has been determined, and the metal macroscopic flowing behavior has been attributed to visualize.Based on the FEM, the deformation modes of the column and the ring compression were analyzed, and the rule of metal flowing was obtained under the different compression conditions. The mechanics mechanism of metal flowing was investigated during the different deformation process. The results show that the stagnant zones expand and shift towards the left with height-diameter ratio increasing, and the strain in the plastic area changes into three coexistent modes from the single compression mode.For the different types of extrusion deformation, the rule of metal flowing was investigated by simulation and experiment. Deformation zones were divided, and stress-strain was analyzed during the forming process. The results show that the plastic zones decreases significantly with modular angle and deformation increasing, and the strain in the plastic zones changes into three coexistent modes from the single elongation mode; the male die with inner cone may eliminate the metal split-flow in the flat bottom of the male die during the forming process; compared with the non-lubrication case, the relative displacement reduced 69.7% by use of the active friction, thus it can be concluded that the active friction may significantly reduce the non-uniform of metal flowing, and be helpful to improve the product quality.An axisymmetric model and a 3D complex model were built, in which different deformation mode were coupled. With the above forming rule of three basic deformation mode, the closed-die forging process was analyzed during the different stage and at the different zones, and the rule of metal flowing was obtained in the coupled forming process. The distribution character of plastic zones and the interface configuration of metal flowing in the different die cavity were also given. The mechanics mechanism of metal flowing was disclosed during the forming process.A new measuring method, in which a few rings of screw threads was used, was put forward in order to solve the difficulties of measuring the strain and the streamlines distribution during the closed-die forging process. In the method, it does not need substitute material to measure the magnitude of three-dimensional plastic deformation during the closed-die forging process, which can be the references to quantitative analysis. Using the method, the strain and the four streamlines of typical sections were measured and analysed during the deformation of a coupled model. The distribution rule of stress-strain was given quantitatively. It is an effective method to measure and analyse the metal flowing of closed-die forging.