Plastic Hinge In Rotary Forging Ring And Disc Parts

Rotary forging is a continuous and incremental forming process. Because of its characteristics of labor and energy saving, little vibration and noise, easy to achieve mechanization and automation, it has been given serious attention, and widely applied in plastic forming process. Ring and disc parts occupy an important share in the application of rotary forging process.Deformation mechanism of rotary forging is complex, and now a number of scholars at home and abroad had analyzed it from the most simple ring and disc parts to guide practice,and had got a number of conclusions. Most of these conclusions are for active deformation zone, and little for the passive deformation zone. Nevertheless, plastic hinge that this article just wants to study just lies in passive deformation zone.Plastic hinge is a kind of status of passive deformation zone when it occurs plastic deformation and it is one of the non-steady-state factors in rotary forging ring and disc parts. It can cause the redistribution of internal forces, and affect the rotary forging process and properties of parts, so it is necessary to research it. The existence of plastic hinge in rotary forging was firstly put forward by Britain's Robin Hood, and then many scholars proved it by experiments or theory methods, and brought plastic hinge models, but the models was not same. Zhang Meng Professor obtained the generating conditions of plastic hinge in rotary forging ring and disc parts by theory derivation. At present, these conclusions about plastic hinge in rotary forging are not perfect and did not form a unified understanding on its state, so some problems of plastic hinges have yet to be studied, for example, its formation and status.This article established the three dimensional models of work-piece and dies, and imported them to the DEFORM-3D software in the STL file format firstly, and then set parameters for simulating the process of rotary forging ring and disc parts. Base on analyzing the simulation results, this article got the evolution process and state of plastic hinges in rotary forging ring and disc parts, summarized the equivalent stress and strain-rate distribution of the plastic hinge area and the equivalent strain distribution in the whole parts, analyzed the variation of grain size of the plastic hinge area, and compared the similarities and differences between plastic hinges of ring and disc parts. In addition, this article also researched the impacts of the original ratio of height to diameter, the friction coefficient of contact surface between parts and cone die, the angle of cone die and the feed of low die on the produced conditions and evolution process of plastic hinges in rotary forging ring parts by changing the four technology parameters. The results will be helpful to gain a better understanding of plastic hinge, and are important supplements to the theories of rotary forging.