Rolling Mechanism And Process Optimization Of Large Titanium Alloy Cylinder

Titanium alloy is favored for its excellent mechanical properties and has become an important material in many fields,such as aerospace,ocean exploration,biomedicine and so on.It plays an indispensable role in developing new technologies and industries,it also enhances the overall national strength in the 21 st century.As the basic parts of the key equipment in the development of nuclear power equipment,petrochemical equipment,deepsea probe and other resources,titanium alloy barrel is the key to realize the transformation of our equipment manufacturing industry from large to strong.At present,the domestic processing technology mainly adopts the free forging process.Its finished product precision is poor,and the manufacturing cost is high,the production efficiency is low.The tubular rolling has the advantages of integrated forming,high material utilization rate and high production efficiency.It is an efficient processing and manufacturing method,which is of great significance for breaking through the limitations of the dimension and structure of the tube joint.Based on the rolling theory,the rolling forming process of large titanium alloy tube is proposed in this paper.The Gleeble compression experiment was carried out to study the deformation behavior of TC4 alloy at the deformation temperature of 900℃～1050℃ and different strain rates,the influence of deformation rate,temperature and deformation degree on the deformation resistance was analyzed.According to the experimental data of TC4 alloy,the Johnson-Cook model of TC4 alloy’s deformation resistance was derived,and the corresponding hot working diagram was established,and the range of temperature and strain rate suitable for TC4 material processing was analyzed.According to the rolling theory,the conditions of biting and forging through the large cylinder joint were deduced,and the force analysis of the cylinder joint rolling element was carried out.The mathematical model of the rolling force was established,and the equations of the rolling force in the elastic compression zone,the front sliding zone,the rolling zone,the back sliding zone and the elastic recovery zone were constructed to calculate the rolling force.Particle Swarm Optimization(PSO)was used to optimize the pitch height,driving roll radius and core roll radius in the rolling force model.The rolling process of large titanium alloy barrel was simulated by Abaqus,the plastic deformation law and roundness change law of metal were analyzed,and the rolling schedule of barrel was formulated.By analyzing the rolling results of large titanium alloy barrel rolling under different rolling process parameters,such as heating temperature,rolling ratio,feed speed of core roll and drive roll speed,the main process parameters of barrel rolling were optimized.