Study On Hot Rolling Process Of TC4 Titanium Alloy Sheet

Titanium alloy is valued in various fields because of its low density,high specific strength,corrosion resistance,good stability and excellent comprehensive performance.However,it has high deformation resistance,low thermal conductivity,difficult rolling forming and low yield,which leads to high price.In order to make the application of titanium alloy more and more to the civilian field from the traditional aerospace and military fields,the low cost preparation of titanium alloys is a hot research topic in our country.The processing loss can be reduced and the manufacturing cost can be reduced greatly by optimizing the heat processing parameters such as deformation temperature,deformation amount and strain rate.In this paper,the hot rolling process of TC4 titanium alloy was simulated by the constant temperature and constant strain rate Gleeble3800 thermal simulation compression experiment.The study of this paper has important theoretical significance for the thermal process of TC4 titanium alloy sheet and the optimization of microstructure control process,the main results are as follows:(1)The influence of different process parameters on the rheological stress curve is analyzed,and it is found that the thermal deformation mechanism of TC4 titanium alloy is mainly dynamic recrystallization in the two phase zone,and dynamic recovery is the main in high temperature single-phase zone;The rheological stress of TC4 titanium alloy is influenced by strain rate and deformation temperature greatly.The rheological stress decreases with the increase of temperature and the decrease of strain rate;Based on the hyperbolic sinusoidal model of Arrhenius equation,the constitutive model including strain parameters is constructed,which can predict the relationship of stress and strain accurately.The influence of different thermal deformation conditions on microstructure evolution was analyzed by metallographic observation.(2)The thermal processing diagram of TC4 titanium alloy was established,the safe zone and unstable zone of TC4 titanium alloy at high temperature deformation were determined,and the optimum deformation technology of TC4 titanium alloy was obtained based on the dynamic material model.(3)Based on the finite element software Msc.Marc,the three-dimensional model of hot rolling is simulated and analyzed,and the experimental and theoretical values of rolling force and surface temperature after rolling are compared to verify the accuracy of simulation.The optimum processing technology is validated by observing the microstructure of the sheet after rolling.