Research On Macro-Micro Coupling Numerical Simulation Of Hot Ring Rolling Based On Drum-Shaped Ring Blank

Hot ring rolling is a plastic processing technology, which makes the ring apear continuous plastic deformation of local area with the help of ring rolling machine, to reduce wall thickness,enlarge diameter and shape section contour. It has been widely used in machinery, energy,transportation and other industrial fields, and it can be used for manufacturing seamless rings with various dimension and cross section shape. Compared with other production methods of ring, it has many technological and economic advantages such as efficient production, wide range of products, energy saving.Hot ring rolling technology is a complex plastic forming process with interaction between macro-deformation and microstructure evolution influenced by multiple factors. In the process of forming, requirements of ring size need to be satisfied, besides, the grain size also need to be controlled to reduce grain size and improve synthesis mechanical properties of ring. Up to now,great progress on the macro and micro research about hot ring rolling has been acquired, but most of them are based on rectangular-section ring blank. However, ring blanks are always with the drum-shaped feature in the real production, and relative researches about the macromicroscopical characteristics of drum-shaped ring blanks in hot ring rolling are less, especially about microstructure, therefore, it is pressing to implement some deep sdudies on this.In this paper, the investigation focus is the macro-microscopical characteristics of drumshaped ring blank in hot ring rolling. Firstly, the reasons for the formation of drum-shaped ring blank were analysed, according to the geometrical characteristics of drum-shaped ring blank, the simplification idea was put forward. Secondly, the finite element model of hot ring rolling was bulit by the FEM simulation software Simufact11.0. Based on this mode, macro-mircoscopical characteristics about hot ring rolling processes of drum-shaped ring blank were analyzed. The simulation revealed the macroscopical forming laws and microstructure evolution included the change laws of geometrical shape, temperature, equivalent strain, forming load, dynamic recrystallization and grain size. And based on this, through the discussion on the influence of feed every revolution, ring blank's initial temperature, radius ratio of main roll to mandrel roll and main roll rotate speed by the method of single factor, the four factors were defined to arrange an orthogonal experiment which was applied to confirm the extent of influence on the ring's microstructure evolution. The result of the orthogonal test was feed per rotation > main roll rotate speed > radius ratio of main roll to mandrel roll > ring blank's initial temperature. Finally,the hot ring rolling process based on drum-shaped ring blank was verified in real practical production.In this paper, through the finite element numerical simulation and the fundamental theory of hot ring rolling, the macro-microscopical characteristics of hot ring rolling process based on drum-shaped ring blank and the influence of processing parameters on the microstructure evolution were analyzed. The results provide guidance for controlling the forming process of hot ring rolling accurately, designing reasonable processing parameters and optimizing processing program. What is more, it has great significance for improving the quality of ring products.