Study On Roll-cutting Forming Method And Its Implementation Equipment Of Conical End Blank

With the rapid development of transportation industry,the demand of axle products such as high-speed railway axle,heavy axle,automobile half axle is increasing day by day.Mass production of shaft parts is one of the main means to meet the market demand.The traditional forging process is difficult to realize the mass production,high efficiency and low cost of such shaft parts.Cross wedge rolling(CWR)is a new plastic forming technology of shaft parts,which belongs to the intersection of metallurgical rolling and mechanical forging.It is the extension of metallurgical rolling technology and the development of mechanical processing technology.Compared with the traditional cutting and forging process,CWR has the advantages of significantly reducing the comprehensive production cost,improving the production efficiency and improving the utilization rate of materials.In the actual production of CWR shaft parts,the axial flow speed of the metal in the center of the rolled piece is slower than that of the surface metal,which often cause the concave defects in the axle ends.The concave part must be cut off to ensure the quality of the axle part.Therefore,the stock to be rolled needs to be reserved,resulting in the material utilization rate of CWR process is usually less than 85%.The most effective way to realize the near net shape of CWR without head is to prefabricate the end of the billet for CWR into special shape(such as cone,inner arc,outer arc,and round table shape),and then "fill" the concave part of the material in the process of CWR,and finally reduce or even eliminate the end concave.Forging,turning,roller shearing and hot shearing are the processes to prefabricate the end of blank into special shape,which have the defects of waste of material,low efficiency,poor quality of forming,complex forming equipment and low stability.In order to form a large number of high quality special-shaped ends blanks continuously,the roll-cutting forming method was purposed in this paper.Forming the conical end blanks commonly found in special-shaped ends blanks was taken an example.Then the key technology of the roll-cutting forming conical ends blanks and its forming equipment were studied.The finite element software of DEFORM-3D was used in the paper.The methods of theoretical analysis,numerical simulation and experimental verification were combined to carry out this work.The conical end blank roll-cutting forming method,end forming quality and forming equipment were studied.The main contents are as follows: 1)combined with the slip line field method,the root cause of the stacking in the process of theconical end blank cutting is clarified,and the influence of the height of stacking on the end concave is studied by CWR experiments;2)the finite element model of the roll-cutting forming conical end blank is proposed and established,the forming process of the conical end blank is simulated,and the feasibility of the roll-cutting forming of the conical end blank for CWR without the stub bar is verified theoretically;3)The forming quality of the conical end blank is affected during the forming process.Based on the analysis of the key influencing factors of the force and energy parameters,the law of metal flow and the change law of the relevant force and energy parameters in the roll-cutting forming process are obtained.Considering the energy consumption and processing efficiency of the equipment,a group of optimal process parameters are optimized for this conical end blank.4)based on the best process parameters and the relevant force and energy parameters,the key parts are designed and calculated.The structural parameters and the strength of the key parts are checked.The rolling forming equipment of the conical end blank is developed.The deviation between the forming size of the conical end and the simulation size is analyzed through the rolling forming experiment of the conical end blank.The results show that the experiment is basically consistent with the simulation,which verifies the feasibility and superiority of the designed roll-cutting mechanism in the actual operation.Results of this paper provide a new real-time on-line blanking technology and practical operation equipment for CWR without stub bar.Also,the conditions for the promotion of near-net forming technology of CWR are created.