Effect of equivalent feed amount per revolution on cold rotary forging process by 3D elastic–plastic dynamic explicit FE method

Abstract

Cold rotary forging is an advanced and very complex incremental metal forming process with multifactor coupling interactive effects. Previous research is mainly based on experimental and analytical methods and thus cannot provide full details on the deformation characteristics and mechanisms of cold rotary forging. In the current work, a decisive factor in cold rotary forging, namely equivalent feed amount per revolution , is first determined, and its mathematical expression is presented. A reasonable three-dimensional elastic–plastic dynamic explicit finite element model of cold rotary forging of a cylindrical workpiece was established under the ABAQUS software environment. Through numerous simulation calculations and the analysis of equivalent plastic strain, it has been found that there are three plastic penetrating states of the cylindrical workpiece under different . On the basis of these plastic penetrating states, the effect laws of on the metal flow, degree of inhomogeneous deformation of workpiece and force and power parameters have been investigated, and thus, the deformation characteristics and mechanisms of cold rotary forging have been thoroughly revealed. The results show that with increasing , the ‘mushroom’ effect of the deformed cylindrical workpiece becomes less obvious and the deformation becomes more homogeneous, while the maximum axial forging force and forging moment gradually increase. Second, the effect of by changing the inclination angle γ of the upper die on the cold rotary forging process is different from that by changing the feed rate v of the lower die or the rotational speed n of the upper die.

Keywords:

• Cold rotary forging
• Equivalent feed amount per revolution
• Equivalent plastic strain
• Plastic penetrating states
• FE modelling

The authors would like to thank the Natural Science Foundation of China for Distinguished Young Scholars (grant no. 50725517), Natural Science Foundation of China (grant no. 51105287) and State Key Laboratory of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology (grant no. 2011–P05) for the support given to this research.