Research on the inner grain evolution and distribution during stretching of shaft heavy forgings

It´s an important method to improve the mechanical properties of forging by studying variation of the crystal grain and realizing the quantitative prediction of the forging process. The inner grain evolutionary model during stretching of shaft heavy forging was established by the microstructure project module based on the cellular automata method of Deform-3D software. The variations and distributions of the grain size in each character region during stretching were simulated. It shows that the equivalent strain increases with increasing the stretching reduction, which leads to an increase in the dislocation density and results in a dynamic recrystallization of the grain. The grain size decreases with increasing the stretching reduction. The distribution of the equivalent strain during stretching is nonuniform, the center of forging P₁ is the easy deformation region, having the maximum equivalent strain; the contact areas P₂ between the forging and the upper or lower anvils is the difficult deformation region, having the minimum equivalent strain; the wall side area of forging P₃ is the middle deformation. P₂ has the maximum grain size, P₁ has the minimum grain size, and P₃ has the middle one under the same stretching reduction.