Forging Simulation Of Hydraulic Cylinder Parts And Forging Defects Analyses Based On DEFORM-3D

With the establishment and development of plastic mechanics for several centuries, the finite-element method (FEM) simulation by means of the plastic constitutive equations has been achieved rapidly with the progress of computer technology science 1960, FEM Simulation technology made a breakthrough progress in the field of plastic molding. Using this numerical simulation technology, the changes of internal temperature, stress, strain and other parameters of workpieses during the actual plastic forming process can be achieved. Then we could develop the best forging process in order to avoid blind trial manufacture, reduce research and development cost greatly. Therefore, it is an effective means in the actual forming process and development of new products.In this paper, by means of commercial metal forming finite-element software DEFORM-3D, the whole forging process of the 1300 style piece has be simulated. By which the changes of the temperatures, stresses and strains at different regions of the billet during the entire forging process has be obtained. Based on the strain distributions of the forged billet, the forming defects analyze was proceeded and it is concluded that some forging defects or flaw may occur near the head surface or around the side edge during the plastic deformation process.In order to further research and analysis of plastic deformation characteristics of the billet in the forging process, the more researches has be done as follows: (1) the impact of the press-in distance and friction coefficient of the head facet on the plastic deformation characteristics; (2) the free end impact during the drawing-out process and contrast of LZ forging to FM forging; (3) by means of computer simulation and the rigid-plastic mechanical model of the square column upsetting, that the tensile stress exists in its central passive plastic deformation region during upsetting process has be proved. The results show that: (1) With the single press-in distance increase, the stress of the side and side edge reduced significantly, at the same time, the area of the difficult deformation zone (near the head face of the billet) also decreased; (2) the small the friction coefficient between anvil and blank is, the more uniform the distribution of stress on the head face of the billet, the greater the average value, and the plastic deformation level of the center regions of the billets is greater; (3) the existence of free-end factors strengthen the plastic deformation of the center part in the compression blank when using the LZ forging, and a "V" type plastic deformation zones (open towards free end) was formed; (4) the use of FM stretching, the existence of free-end factors makes the plastic deformation zones of the compression part move up when using the FM forging, the plastic deformation level of the center area is very small, and which mainly concentrated in and around the upper half of the compression part.In addition, the paper has also used computer simulation combine with the microstructure experiments analyzed the cracks on the surface and edges of the forged billet. Consider that the main reason for the cracks is the stress concentration near the forging surface and edges and the subsidiary stress, which made the serious burning metal surface crack.