Research On Spinning Forming Technology Of Spherical Gas Cylinder

Spinning is an advanced plastic forming process without cutting,which is a forming process that needs to be prioritized in the processing of thin-walled rotating parts.In order to meet the requirements of component reliability and light weight and heat resistance and corrosion resistance in the aerospace industry,thin-walled rotary parts made of lightweight heat-resistant materials such as titanium alloys have important applications in aerospace and other fields.However,the forming and manufacturing of titanium alloy parts is more difficult than ordinary structural materials,and the large thin-walled cylindrical parts of titanium alloy are easily deformed during cutting,the cutting is difficult,the processing cost is high,and the titanium alloy material is poor in plasticity at normal temperature.Not easy to spin molding.In this paper,the semi-spherical hemisphere of titanium alloy spherical gas cylinder is taken as the research object,and the spinning forming method is studied by multi-pass hot spinning technology.The main research contents are as follows:(1)The mechanical properties of titanium alloy wound composite cylinders were tested to study the mechanical properties of TC4 titanium alloy at different temperatures.Under the condition of medium temperature,the titanium alloy will not produce back-squeezing phenomenon,but the material plasticity is still poor.The parts will be cracked with the work hardening.At high temperature,the back-squeezing phenomenon will occur when the distance between the rotating wheel and the mold is too small.The anti-extrusion phenomenon is common in ordinary spinning of sheet metal.(2)Perform multi-pass spinning on the profiled plate,and analyze the trajectory of the linear trajectory and the arc trajectory in the first pass of the spin forming.The arc trajectory is more compact than the linear trajectory.The ability to help the sheet to close the neck.Spinning experiments were carried out to understand the spinning performance of titanium alloy parts and to ensure the basic forming of the parts.Appropriately increasing the number of spinning passes,i.e.reducing the amount of reduction between each pass,can facilitate the spinning process and ultimately spin out the qualified process parts.(3)In the first stage of the test,there were two kinds of spinning defects such as circumferential cracking and back extrusion.Through the second-stage spinning test,considering the amount of deformation of the rotating wheel,the compensation of the wheel gap has a compensation amount of 0.7 mm,which can improve the back-squeezing defect;the final one-time finishing process in the multi-pass spinning,and the appropriate heat treatment to improve the cracking phenomenon To ensure the quality of the outer surface of the part.(4)By measuring the wall thickness of the hemispherical spinning parts,the simple multi-pass spinning is not suitable for difficult-to-form metal and work hardening sensitive materials,and it is necessary to assist the flame heating and heat treatment to ensure complete forming of the parts.(5)Comprehensive analysis of the finished titanium alloy hemisphere spinning parts,according to the distribution of stress and strain in each part of the deformation process,it is divided into four parts,namely dead zone,deformed zone,main deformation zone and to be deformed zone.Th e main deformation zone is affected by the axial tensile stress z,the radial compressive stress r and the tangential pressure,resulting in deep drawing deformation.The strain state is one-way stretching and two-direction compression,and the blank is subjected to stretching and bending long and thin.