Research On Manufacturing Process Of Titanium Alloy Bellows Based On Diffusion Bonding

Metal bellows are usually used as sensors,components,sealing elements,structural elements and components for energy storage because of having function of displacement compensation,noise damping and sealing features.Stainless steel bellows are made by hydraulic bulging and machinical manufacturing,which are used everywhere.But the pipe wall decreases significantly,prone to failure in high temperature corrosive medium.Titanium alloy bellows character by low density,corrosion resistance,high temperature strength,but titanium alloy is not fit for cold forming because of its poor forming property in cold state.There are few researches on the manufacturing of titanium alloy bellows,and it is hard to manufacture titanium alloy bellows by using hydroforming,rolling,spinning.Therefore,to find a new method of manufacturing of metal bellows is of great significance.In this thesis,a method based on diffusion bonding of titanium alloy bellows manufacturing technology are as follows:(1)According to the characteristics of titanium alloy v-shaped bellows structure,propose the method of manufacturing process route planning and the method to determine the results.(2)Conduct the Ti6Al4 V alloy diffusion bonding test and high temperature stress relaxation test,and obtain suitable test parameters for diffusion bonding and high temperature stress relaxation test parameters,set the foundation for bellows diffusion bonding test and stress relaxation process.(3)Dsign the structure of bellows;conduct bellows diffusion bonding test and stress relaxation test.(4)Perform gas-tight test and stiffness test on bellows,air tightness test shows that bellows withstand 0.5MPa pressure for 60 minutes without leaking,experimental stiffness value is 113.1N/mm,empirical formulas calculate stiffness of corrugated pipe is 181.2N/mm,a difference of 60%.Cut bellows from axial direction to observe the section,finding that the final interface agree well with simulation results.Mechanical test on furnace of test specimens at room temperature shows that yield strength decreases by 8.6%,tensile strength decreases by 8.8%,extending property enhanced by 13.4%.(5)A new bellow with different parameters was made by the same method,and the stiffness and tightness test show that sealing property is great and stiffness value and the measured value differ by less than 50%The above study showed that titanium alloy bellows made by diffusion bonding method is feasible and has broad prospects for development,providing a reference for solving bellows made of titanium alloy.