Effect of rolling passes on thermal parameters and microstructure evolution via ring-rolling process of GH4738 superalloy

As a key part of the aeroengine, the importance of seamless ring is self-evident. Obviously, the uniformity of thermal parameters and microstructure evolution of seamless ring has an extremely significant effect on its mechanical properties and service life. In this paper, a 3D FEM model was developed to analyze the influence of different rolling passes on thermal parameters and microstructure evolution via ring-rolling process of GH4738 superalloy. Meanwhile, two groups of experiment were designed: single-pass rolling with large deformation and multi-pass rolling with small deformation in each pass. Through comprehensive analysis of the results, conclusions can be summarized as follows. (1) The temperature distribution is more uniform under the condition of multi-pass rolling with small deformation in each pass. (2) The effective strain distribution is more non-uniform under the condition of single-pass rolling with large deformation. (3) Single-pass rolling with large deformation leads to smaller grains, while multi-pass rolling with small deformation leads to more homogeneous microstructure and less mixed crystal phenomenon. (4) We can, through distributing the deformation of each rolling pass reasonably, improve the thermal parameters and microstructure distribution.