Research On Residual Stress In Hot Forming And Quenching Process Of 2A14 Aluminum Alloy

2A14 aluminum alloy are widely used in the aerospace,commercial transportation and other industries due to its high strength,good forging and thermoplastic,good weldability,high temperature and so on.Large aluminum alloy conical ring are generally important parts of rocket shells,their performance is directly related to the rocket’s safety.Traditional conical ring is usually forged to straight ring first,and then machining of conical ring,this processing method waste materials and time.At this stage,hot ring rolling is widely used to manufacture such difficult deformation shaped ring with the advantage that save energy and materials,high quality and efficiency.But during the process of hot-rolling and quenching,a lot of residual stress are produced and it will affect the processing and using of ring.So it is necessary to study on the hot-rolling and quenching process of 2A14aluminum alloy conical ring.Based on the hot compression experiment,we analyzed the hot deformation characteristics of 2A14 aluminum,established its high temperature stress-strain constitutive model,observed hot deformation micro organization with metallographic microscope,researched the effect of hot deformation parameter on microstructure transformation.And based on dynamic material model,we established the hot processing figure of 2A14 aluminum alloy,find its best hot processing parameter range that deformation temperature is 430-470℃,strain rate 0.01-0.3S^-1.With ABAQUS/Explicit platform,we established hot-rolling 3D thermal-mechanical coupling model of the conical ring and conical ring hot-rolling experiment was carried out,by comparing the test value and simulated value of the macroscopic dimensions of conical ring,the reliability of finite element models are verified,and the macro-forming of conical ring performance are analyzed.Through the study of variation of stress field on hot rolling process,we analyzed the causes of residual stress and the distribution of residual stress.We analyzed the effect of the blank’s initial temperature,drive roll feed rate and drive roller speed on residual stress,we came to a conclusion that residual stress decreases with blank initial temperature increases,drive roll feed speed increases,rotating speed of the driven roller increases.Finally,according to the measured cooling curve of 2A14 aluminum during quenching in water at different temperatures,heat coefficient is calculated and found it first increases and then decreases as quenching medium temperature.Using the method of sequential coupling,we established a axisymmetric quenching finite element model and analyzed the variation of temperature field and stress field in the quenching process,studyed the effect of quenching medium temperature and axisymmetric height-diameter ratio on the quenching residual stress.And by studying the stress evolution of the rolling conical ring during the quenching process,we found suitable quenching is benefit to reduce residual stresses of ring rolling,as well as appropriately reducing residual stresses of ring rolling helps to reduce the final residual stress and thus make stress distribution more uniform.