Research On Forming Quality Of Pre-rolling High-temperature Ring Rolling Of Large Thin-walled 2219 Aluminum Alloy Ring

Large seamless rings are widely used in trains,ships,aerospace and other industrial fields.National Aerospace Major Science and Technology Project——the key structural parts required for the launch vehicle are large aluminum alloy rings.With the development of the national aerospace industry,there is an urgent need for high-performance large aluminum alloy rings.Microstructure prediction has a positive significance for predicting mechanical properties in ring rolling.Because the dynamic recrystallization will affect the grain size of the ring after rolling,it is necessary to study the dynamic recrystallization behavior of large ring during the gap time of radial-axial hot ring rolling,so it is necessary to establish the dynamic recrystallization model and determine the deformation conditions suitable for hot deformation.There are two deformation zones of different passes in radial-axial hot ring rolling,which makes the deformation behavior very complex in this zone.Complex deformation not only affects the stability of rolling,but also brings quality problems such as mixed crystal,ellipticity and stacking.For large-scale ring parts,reasonable ring blank design is conducive to obtaining excellent structure performance and highprecision shape.Optimization of rolling curve design plays a significant role in improving the forming quality,structure uniformity and controlling temperature rise.The particularity of its design is an important problem to be solved urgently in hot ring rolling of ring parts.In this paper,2219 aluminum alloy is taken as the research object.By analyzing the stressstrain curve of the material,the characteristic parameter model is established.According to the modified Avrami equation,the dynamic recrystallization dynamic model of 2219 aluminum alloy is established,and the recrystallization grain size model expressed by deformation temperature and strain rate is established.Based on the analysis of dynamic recrystallization degree and size,a suitable processing window is obtained.The ranges of rolling ratio and radial-axial deformation distribution ratio in different ring blank modes are determined through the design of the ring blank.The basis of ring blank design is given and optimized.At the same time,the design of “high rolling section” is proposed for the rolling curve,and the rolling curve equation is determined,which provides a strong basis for improving the forming quality.Based on ABAQUS finite element software,this paper applies the designed rolling curve to the hot-rolled finite element model of large aluminum alloy ring with real-time radial and axial feed.The simulation analysis of hot rolling expansion reveals the influence of different rolling curves on the macroscopic forming quality of the ring.In addition,by comparing and analyzing the ring data of the RAM8000 CNC ring rolling machine,the correctness of the ring blank and rolling curve design is verified,which provides a theoretical basis for optimizing the hot-rolling forming process of large aluminum alloy rings.