Research On Cold Power Spinning Of Ultra-thin Walled Aluminum Alloy Pressurised Tube

This subject taken the ultra-thin walled aluminum alloy pressurized tube as the research object.The forward spinning finite element model of mandrel rotation which is conform to the actual working condition was established in ABAQUS.By comparing the difference between ultra-thin walled tube and thick walled tube in cold power spinning,we obtained the mechanism of cold power spinning of ultra-thin walled aluminum alloy tube.We found that the deformation of ultra-thin walled aluminum alloy tube in the thickness direction is more uniform because of the thin wall thickness.The inner and outer layers of metal deformed almost simultaneously.In addition,the ultra-thin walled tube had poor rigidity and less deformation constraints.Both ends of the contact zone were prone to warp,resulting in a series of spinning instability defects.The fittability was a difficult technical problem that had puzzled the stable and continuous production of this product for a long time.This study selected this technical difficulty as the main research direction.We attempted to conduct research and explore the law from multiple viewpoints.Finally,we obtained effective control schemes that can guide production.The research aimed at dealing with the fittability in the cold power spinning of ultra-thin walled aluminum alloy tube.Based on the evaluation indexes such as inner diameter expanding,inner diameter straightness and inner diameter ovality,we studied the effects of various parameters on the fittability in the cold power spinning process of ultra-thin walled tube.It was found that the radius of the roller round corner affects the overall fittability.The roller diameter affected the axial fittability.The roller forming angle had little effect on the fittability.As the single pass thinning rate increased,the overall fittability decreased.Too large or too small feed rate would affect the axial fittability,but feed rate had little effect on the circumferential fittability.The fittability of ultra-thin walled tube in cold power spinning was extremely sensitive to the mold clearances.The lubrication state had little effect on the overall fittability,but there were no obvious defects on the inside of the tube wall when lubricated.The structural design of the spinning mold was carried out by the combination of optimized process parameters obtained through the single factor method.Due to the poor forming precision of the ultra-thin walled aluminum alloy tube in the large thinning rate power spinning,the tension spinning was introduced for simulation analysis.By the stress theory of the deformation zone,the stress-strain distribution,the spinning force and the forming precision,we knew the difference between the power spinning and the tension spinning in the large thinning rate power spinning of the ultra-thin wall tube.We found that tension spinning not only had more uniform deformation,but also had better fittability and higher forming accuracy.By comparing the one-way spinning and the interactive spinning,the latter improved the circumferential fittability by restrain the diameter enlargement at the top of the tube.It avoided the external surface tearing caused by circumferential distortion.On the basis of tension interactive spinning,the research investigated the influence of variable feed state and variable tension state on the fittability.It was found that the deformation is more uniform and the forming precision is higher under the condition of increasing the feed rate between different passes and decreasing tension in the same pass.