Study On Control And Distortion Analysis Of Welded Slender Beam Of Titanium Alloy In Manufacturing Process

Owing to its great intensity,good resistance to high temperature and chemical corrosion,and excellent performances,titanium alloy is widely used in aerospace engineering.Meanwhile,due to its massive structural size,high material removal rate and thin wall,slender beam of titanium alloy has obvious distortion problems in electron beam welding,machining and heat treatment process.Therefore,in this paper,the study on distortion analysis and control of welded slender beam of titanium alloy in manufacturing process has been carried out using numerical simulation,analytical analysis and instance verification.The main research contents and achievements are as follow:(1)Setting up a three-dimensional analysis model of welding joint,the distribution of the temperature filed and residual stress of welding seam after welding were analyzed by thermal-elastic-plastic finite element method.Finally,the distribution characteristics of welding residual stress were obtained.(2)The measurement of internal stress and residual stress after welding of titanium alloy forgings was completed.Based on the results of stress measurement,the theoretical and simulation analysis of machining distortion of the thin slender beam was carried out to establish a method to control the machining distortion through parts location and finishing allowance.(3)For heat treatment correction after welding and machining,the titanium alloy U-section beam bending deformation of thermal simulation and theoretical research were carried out,based on the elastic-plastic theory,combined with high-temperature stress relaxation mechanism.And the straightening theory model of the warp beam and lateral bending deformation were established,respectively.In the end,the heat treatment correction was given.