Study On Flange-Constrained Spinning Process For Thin-Walled Aluminum Alloy Parts

Metal spinning is a main manufacturing method of the fuel tank vessel of large launch vehicle.During metal spinning of large thin-walled aluminum alloy components,weak structural stiffness often causes the flange prone to compression instablity,the wrinkling wave which may result in failure of the spinning process.A spinning method with high forming stablity is necessary in the industry.The stablity of spinning can be increased by applying reasonable constraints on the blank flange.However,this method is still in state of the art,at present,its related deformation theory and process design method is lack.Therefore,the formability of flange-constrained spinning method is studied to provide a technial support for the tank vessel manufacturing.This paper studies the formability of two kinds of flange-constrained spinning method,the forming quality of spun part and the process ability of multi-pass flange-constrained spinning.The details are as followings:1)Aiming at the spinning stability,the formability of two kinds of flange-constrained spinning process and wrinkle prediction modeling were studied,and the influence of flange constraints and process parameters on the wrinkling in aluminum alloy spinning process was analyzed.According to the characteristics of wrinkling waveform during single-side flangeconstrained spinning process,a reasonable deflection equation is established and a wrinkling prediction model for flange-constrained spinning is achieved based on the energy method.The results of spinning tests and wrinkle predictions show that the spinning limit can be increased by applying flange constraints,meanwhile,within a certain range of parameters,decreasing the feed ratio and increasing the roller radius can delay the moment of wrinkling.2)The finite element method was used to study the relationship between the key parameters and the wall thickness uniformity and the fittability in flange-constrained spinning process.The research results show that although the contact area between the roller and blank is large in the double-side flange-constrained spinning(DSFCS),the friction coefficient between the roller and blank has little effect on the forming quality,and that with the increase of constrained gap between the holder and roller,the wall thickness uniformity of flange-constrained components becomes worse but the fittability is almost unchanged,in addation,with the increase of feed ratio and roller raidus,the wall thickness uniformity becomes better but the fittability becomes worse.3)Compared with the traditional spinning process,the process ability of multi-pass flange-constrained method is studied on the aluminum alloy hemispherical spun part.The multi-pass flange-constrained spinning results of the aluminum hemispherical part with 80 ration of diamater-tothickness show that the flange-constrained spinning method can improve the wall thickness uniformity and the fittability of the hemispherical part,at the same time,and reduce the number of forming passes.The main reason for better wall thickness uniformity is that the stress distribution in the roller-located area and the zone of flange area is relatively uniform during flange-constrained spinning process.Compared with single-side flange-constrained spinning(SSFCS),improving of the forming quality in DSFCS is more obvious.