Dynamic Recrystallization Behavior Of 2219 Aluminum Alloy During Ring Rolling

2219 aluminum alloy ring is mainly used for the connection part of large aerospace important components.Due to the combined effect of high-temperature and high-pressure environment,the performance of the ring is highly required.Radial and axial rolling(hereinafter referred to as ring rolling)is an important process for producing high-performance large aluminum alloy seamless ring.And the ring rolling process involves many nonlinear problems such as thermal-mechanical coupling,coordinated motion of multiple rolls,ring microstructure evolution and so on.In the forming process,it is prone to uneven grain size and coarse grain.Dynamic recrystallization is an important means of grain refinement in ring forming process.Therefore,the dynamic recrystallization behavior of 2219 aluminum alloy during ring rolling was studied as follows.1.The hot forming behavior and dynamic recrystallization behavior of 2219aluminum alloy at different deformation temperatures(410?470°C)and strain rates(0.01?5s^-1)were investigated by hot compression experiments.Based on Arrhenius and Avrami equation,the constitutive model of 2219 aluminum alloy was established.The values of AARE of the flow stress and the dynamic recrystallization grain size(9₍₉₀₎between the predicted and experimental of the constitutive model were 5.36%and4.78%,respectively,and the Pearson'r coefficients were 0.98095 and 0.99815.2.The ring rolling process parameters such as the function curve relationship between the instantaneous feed of the core roll and the time were obtained through the statics of ring rolling and the rolling kinematics relationship.The finite element simulation model of ring rolling based on the constitutive model of 2219 aluminum alloy was established.3.The macro deformation parameters(strain,temperature)and dynamic recrystallization related parameters(recrystallization volume fraction,grain size)were calculated by finite element simulation of ring rolling process under different roll size and core roll feeding mode.The results show that:(1)With the increase of roll size,the volume fraction of dynamic recrystallization increases and the average grain size decreases.At the same time,too large roll size would lead to the increase of ring temperature,the coarsening of initial grains,the uniformity of average grain size and the uneven distribution of grains.(2)The constant expansion of the outer diameter of the ring in the ring rolling is beneficial to the stable forming of the ring and the improvement of the grain uniformity of the ring.(3)The average grain size between the inside and outside of the ring can be effectively controlled by controlling the size relationship between the driving roll and the core roll,and the mechanical properties of the outside or inside of the ring can be adjusted accordingly.