Macro-Micro Finite Element Numerical Simulation And Process Optimization Of Round Billet In Radial Forging

In recent years,radial forging has been widely used in aerospace,shipbuilding,rail transportation and other equipment manufacturing fields as a special forging technology.Especially in the manufacture of shaft parts,the advantages of radial forging are even more obvious.Once a company forged a solid shaft of ?600mm in diameter,the end face had a serious shrinkage defect after four passes of forging.Cutting the part of end-face shrinks resulted in material wasting,yield reducing,and huge economy lossing.At present,researches on the radial forging face shrinkage are relatively single,most of which only consider the influence that the process parameters exert on the shrinkage of the end face,but do not consider how the changes of the process parameters influence the quality of the forging.In this paper,starting from the improvement of face-reducing defects,the finite element numerical simulation analysis is used to study the macro forming of radial forging and the microstructure evolution systematically to improve the end-face shrinkage defects and the forging quality by developing a new processes.Firstly,based on the Deform,a reasonable finite element model was established to carry out a complete simulation of the original process and compared with the end-face shrinkage of the factory production forgings to verify the applicability of the model.Secondly,the two main research objects in the forming process,the equivalent strain and the axial tensile stress peak of the heart,were determined by analyzing the variation and distribution law of the deformation speed,equivalent strain,axial tensile stress and temperature field in the original process.The single-variable method was used to change the four main process parameters of radial forging such as initial forging temperature,reduction amount,initial feed amount,and friction factor,and the influence of which was studied in forming process and necking defects.Thirdly,the average core grain size was determined as the main research object during the microstructure evolution process by analyzing the variation and distribution rules of dynamic recrystallization percentage,dynamic recrystallized grain size and average grain size in the original process.The single-variable method is used to change the process parameters such as initial forging temperature,reduction amount,initial feeding amount and friction factor,and the influence of which is studied on the microstructure evolution process.At last,based on the maximum forging force of the radial forging machine,reasonable initial forging temperature,initial feeding amount,and reduction amount range are selected,and through the analysis of the previous simulation results,a better improved technological scheme is obtained.A complete simulation is conducted for the improved process plan and compared with the original process,and reached the goal of improving the end-face shrinkage defects and the quality of forgings.