Research On Ovalitys During Hot Power Backward Multi-pass Spinning Strength Aluminum Alloy Tube

Casting high strength aluminum alloy tube parts are important rotational parts which are widely used in many fields, such as aerospace field, auto and military industry.The multi-pass spinning forming process is one of the main forming methods of thin-wall profile. However one of complicated forming processes characterized,involving multi-fields,multi-factors and their coupled effects, elliptic defect was made by forming parameters controlled improperly, and the quality of tube is affected seriously during power spinning forming process. Therefore, an finite element model was established based on the platform of ABAQUS, and the Influence laws of forming parameters on the ovality in hot power backward spinning were analyzed. A brief introduction of this paper and it main results are as follows:(1) 3D-FE model of hot power backward sinning forming of tube parts was based on ABAQUS paltform after solve some key technology problems of forming process, such as geometric model, material mode, mesh, boundary conditions, etc.during the establishing process, actual situation and both computer accuracy and efficiency were taken into account and its reliability was validated by experiment.(2) Based on the FE model, the distributing laws of stress and strain were analyzed in power spinning forming process, the quantitative description of ovality was proposed,the ovality’s production, development and evolution in spinning process were obtained.The results were shown as the follows:In three dimensional uneven loading area workpieces ovality significantly increased;maximum of forming stress in the contact regions between workpieces,ovality also increased obviously.With the development of spinning, the ovality increases at first and then tends to be stable.The first spinning process to 40% ovality tends to be stable.Fourth spinning process to 80%(3) The influence laws of forming parameters(include temperature, feed rate, spindle speed and friction, etc) for ovality in the multi-pass hot power backward spinning for casting aluminum alloy tube were studied systematically by using the model established. The results show that: with the spindle speed increasing, the ovality decreased first and then increased; the ovality affected by the friction in each pass were different, but generally showed a tendency to increase; with the feed rate increasing, the ovality were generally increased first and then decreased, whichpresented parabola change; the higher the preheating temperature, the greater the ovality,the ovality affected by preheating temperature in forth pass was maximum.