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Effect of blank quenching on shear spinning forming precision of 2219 aluminum alloy complex thin-walled components
Chinese Journal of Aeronautics 2023, 36(4): 538-555
Published: 05 December 2022
Abstract Collect

The quenching-spinning (Q-S) process, i.e., shear spinning after blank quenching, has been increasingly utilized to form 2219 aluminum alloy complex thin-walled components. However, the changes in material property, shape and stress of the blanks after quenching will affect the spinning forming precision. In this study, the rules and mechanisms of these effects are investigated based on a combined finite element (FE) model including blank quenching and component spinning process. The results indicate that the increase of material strength and the existence of distortion of the quenched blank lead to a notable increase in the non-uniformity of the circumferential compressive stress in the spinning area and the increase of the flange swing height during spinning. These changes result in an increase in the wall thickness and component-mandrel gap of the components. The quenching residual stress has little effect on wall thickness and roundness but can noticeably reduce the component-mandrel gap. This is because that the existence of quenching residual stress of the blank can lead to the decrease of the maximum circumferential compressive stress of the workpiece in spinning and an obvious drop in the maximum compressive stress after reaching the stress peak. Quenching distortion is the main factor affecting the roundness. Moreover, the optimized installation way of the blank for spinning is obtained.

Open Access Issue
Formability enhancement in hot spinning of titanium alloy thin-walled tube via prediction and control of ductile fracture
Chinese Journal of Aeronautics 2022, 35(2): 320-331
Published: 04 March 2021
Abstract Collect

The damage and fracture in hot spinning of titanium alloy is a very complex process under the combined effects of microstructure evolution and stress state. In this study, their dependences on processing parameters were investigated by an integrated FE model considering microstructure and damage evolution, and revealing the effects of microstructure and stress states on damage evolution. The results show that the inner surface of workpiece with the largest voids volume fraction is the place with the greatest potential of fracture. This is mainly attributed to the superposition effects of positive stress triaxiality and the smallest dynamic recrystallization (DRX) fraction and β phase fraction at the inner surface. The damage degree is decreased gradually with the increase of initial spinning temperature and roller fillet radius. Meanwhile, it is first decreased and then increased with the increases of spinning pass and roller feed rate, which can be explained based on the variations of β phase fraction, DRX fraction, stress state and tensile plastic strain with processing parameters. In addition, the dominant influencing mechanisms were identified and discussed. Finally, the thickness reduction without defect in the hot spinning of TA15 alloy tube is greatly increased by proposing an optimal processing scheme.

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