Numerical Simulation And Experimental Research Of Press Cylinder's Closed-die Hot Forging

The oil pressure cylinder is the working cylinder for pressing plate material when shearing plate of shearing machine.Each device is arranged according to the cut sheet width of dozens of different,which have a large amount of dosage.Due to the high frequency of shearing machine,the stability of the quality of the material cylinder to ensure the quality of sheet shear has a very important role.As the main part of the oil pressure cylinder,cylinder block's quality is directly deciding the performance of the oil pressure cylinder.But,traditional production technology of cylinder block is composed of combined welding and casting.These two approaches are not only ensure the mechanical properties of cylinder forgings,but also with long processing time,low material utilization and high production costs.With the high-speed development of the precision forging technology,it provides a new way for the production of the revolving body or the axisymmetric parts.This method produces not only the metal streamline distribution is reasonable,high mechanical property of forging,short production cycle,high efficiency,but also has merits of high velocity and high efficiency of 30-40%.This paper's research object is based on a certain type of pressure cylinder,trying a approach of combining numerical simulation with physical experiment to study the feasibility of hot closed-die forging process of pressure oil cylinder and die force condition.In this paper,through the analysis of the structure of the cylinder parts,we have designed two schemes: one time forging forming and pre forging + terminal forming.We adopt the approach of rigid-plastic finite element,through DEFORM-3D simulation software to analyse this two methods,finally we select the pre forging +terminal forming scheme.The forming scheme selection based on single factor rotation method is used to study the different extrusion speed,die temperature,punch fillet size and friction's effect on the forging quality and forming load.Finally,the optimum forming parameters are determined.The results show that the forming force is decreased and the forging quality is good when we use the optimum forming parameters.Through the analysis of the whole die and the combined die,the results showthat the maximum effective stress can be reduced obviously and the service life of the die can be improved by using the combined die structure.Then,on the basic of different diameter ratio n,the force and the maximum displacement of the combined die are analyzed,and the optimum diameter of each layer is determined.Finally,on the basic of the physical experiment,we carried out the hot precision forging trial-produce of blocking cylinder by J58K-630 electric screw press.The experimental results show that the forging quality of cylinder block is good,the forming force is small and with no obvious weaknesses,which verifies the accuracy of numerical simulation and feasibility of the process.What's more,it for the actual production to provide a strong basis.