During multi-pass conventional spinning, roller paths combined with the forward and the backward pass are usually used to improve the material formability. In order to understand the backward spinning process properly...During multi-pass conventional spinning, roller paths combined with the forward and the backward pass are usually used to improve the material formability. In order to understand the backward spinning process properly, the backward roller paths of hemispherical parts with aluminum alloy 2024-O are analyzed. Finite element model with parameterized conventional spinning roller paths, which are based on quadratic Bezier curves, is developed to explore the evolution of the stress, strain and thinning during the backward processes. Analysis of the simulation results reveals stress and strain features of backward pass spinning. According to the findings, the application of the backward pass can obviously improve the uniformity of wall thickness. Furthermore, references of the parameters in future backward path design are provided.展开更多
Based on simplified axisymmetrical forming model, a elasto-plastic FEM simulation system of multi-pass conventional spinning is developed. Taking the typical draw-spinning as the study object, and establishing reasona...Based on simplified axisymmetrical forming model, a elasto-plastic FEM simulation system of multi-pass conventional spinning is developed. Taking the typical draw-spinning as the study object, and establishing reasonable mechanics model, research on the first pass of spinning process is carried out with FEM system developed. The distributions of the stress and strain are obtained by three types of roller-trace curves: straight line, involute curves and quadratic curves. The results are as follows: (1) The values of equivalent stress and strain are the lowest under involute curve compared to other two curves, and they change relatively small and decrease with the increase of radius. The values of equivalent stress and strain is the highest under quadratic curves, and increase with the increase of radius. (2) The value of radial stress is smallest under involute curve, and is the largest under straight line. Value of radial stress is often used as the criterion of cracking limit, so its distribution laws can provide references for studying the condition of cracking in multi-pass conventional spinning under different roller-trace. (3) Tangential stress is compressive stress. Absolute value of tangential stress is the smallest under involute curve, and values of tangential stress are close between other two curves. The distribution laws of tangential stress can serve as a significant guide to research the critical condition of wrinkling in multi-pass conventional spinning under different roller-trace. (4) The reduction of thickness is the smallest under involute curve. The distribution of the thickness strain is very unequal under quadratic curves. The results obtained can provide references for selecting reasonable roller-trace in multi-pass conventional spinning.展开更多
A nonlinear FEM program ADINA was employed for analyzing the conventional spinning process. Based on experiments, a calculation model for the initied deformation stage was established. The calculated results include t...A nonlinear FEM program ADINA was employed for analyzing the conventional spinning process. Based on experiments, a calculation model for the initied deformation stage was established. The calculated results include the displacement of workpieces, stress and strain distributions, and the relationship between the spinning force and the axial feed of a spinning roller. Furthermore, a new explanation for the deformation mechanism of workpieces is given in this paper.展开更多
At present, we have succeeded in producing silk noil yarn by rotor spinning, and obtained good economic benefits. In this paper, through combining with the recent producing practice, systematically discussing and anal...At present, we have succeeded in producing silk noil yarn by rotor spinning, and obtained good economic benefits. In this paper, through combining with the recent producing practice, systematically discussing and analysing the technology in the process of producing silk noil yarn by rotor spinning, we develop the new technology which is suited to produce silk noil yarn by rotor spinning, and address several noticable problems. The conclusions have been put into practice and proved to be effective and reliable. It can be consulted by the textile mills.展开更多
In this paper, the process of thermal conventional spinning of Ti-6Al-4V alloy complex shape shell is studied by experiment. Billet for Ti-6Al-4V alloy board is headed in the spinning process for multi-pass convention...In this paper, the process of thermal conventional spinning of Ti-6Al-4V alloy complex shape shell is studied by experiment. Billet for Ti-6Al-4V alloy board is headed in the spinning process for multi-pass conventional spinning forming. With two spinning mandrel, the first is conventional spinning pre-forming and the second is conventional end forming, vacuum heat treatment after each spinning forming. As results, the mandrel preheating temperature impacts the spinning and the appropriate temperature range plays an important role in the process of spinning. With supplemental heating means and infrared thermometer measurement ensure a stable temperature. Multi-passing thermal spinning Ti-6Al-4V alloy thins the billet thickness, using the feature obtaining the wanting complex shape shell of thick bottom and thin mouth. The spinning track, the number of spinning pass, feed rate affect the billet thinning. During thermal spinning process Ti-6Al-4V alloy rebound severe. The size reduction and feed have impact on the rebound. By modifying the spinning parameters and the mandrel repair to ensure the dimensional accuracy of workpiece. Spinning workpiece has fine grain and high strength.展开更多
基金Project(2014CB046601)supported by the National Basic Research Program of ChinaProject(51675333)supported by the National Natural Science Foundation of China
文摘During multi-pass conventional spinning, roller paths combined with the forward and the backward pass are usually used to improve the material formability. In order to understand the backward spinning process properly, the backward roller paths of hemispherical parts with aluminum alloy 2024-O are analyzed. Finite element model with parameterized conventional spinning roller paths, which are based on quadratic Bezier curves, is developed to explore the evolution of the stress, strain and thinning during the backward processes. Analysis of the simulation results reveals stress and strain features of backward pass spinning. According to the findings, the application of the backward pass can obviously improve the uniformity of wall thickness. Furthermore, references of the parameters in future backward path design are provided.
文摘Based on simplified axisymmetrical forming model, a elasto-plastic FEM simulation system of multi-pass conventional spinning is developed. Taking the typical draw-spinning as the study object, and establishing reasonable mechanics model, research on the first pass of spinning process is carried out with FEM system developed. The distributions of the stress and strain are obtained by three types of roller-trace curves: straight line, involute curves and quadratic curves. The results are as follows: (1) The values of equivalent stress and strain are the lowest under involute curve compared to other two curves, and they change relatively small and decrease with the increase of radius. The values of equivalent stress and strain is the highest under quadratic curves, and increase with the increase of radius. (2) The value of radial stress is smallest under involute curve, and is the largest under straight line. Value of radial stress is often used as the criterion of cracking limit, so its distribution laws can provide references for studying the condition of cracking in multi-pass conventional spinning under different roller-trace. (3) Tangential stress is compressive stress. Absolute value of tangential stress is the smallest under involute curve, and values of tangential stress are close between other two curves. The distribution laws of tangential stress can serve as a significant guide to research the critical condition of wrinkling in multi-pass conventional spinning under different roller-trace. (4) The reduction of thickness is the smallest under involute curve. The distribution of the thickness strain is very unequal under quadratic curves. The results obtained can provide references for selecting reasonable roller-trace in multi-pass conventional spinning.
文摘A nonlinear FEM program ADINA was employed for analyzing the conventional spinning process. Based on experiments, a calculation model for the initied deformation stage was established. The calculated results include the displacement of workpieces, stress and strain distributions, and the relationship between the spinning force and the axial feed of a spinning roller. Furthermore, a new explanation for the deformation mechanism of workpieces is given in this paper.
文摘At present, we have succeeded in producing silk noil yarn by rotor spinning, and obtained good economic benefits. In this paper, through combining with the recent producing practice, systematically discussing and analysing the technology in the process of producing silk noil yarn by rotor spinning, we develop the new technology which is suited to produce silk noil yarn by rotor spinning, and address several noticable problems. The conclusions have been put into practice and proved to be effective and reliable. It can be consulted by the textile mills.
文摘In this paper, the process of thermal conventional spinning of Ti-6Al-4V alloy complex shape shell is studied by experiment. Billet for Ti-6Al-4V alloy board is headed in the spinning process for multi-pass conventional spinning forming. With two spinning mandrel, the first is conventional spinning pre-forming and the second is conventional end forming, vacuum heat treatment after each spinning forming. As results, the mandrel preheating temperature impacts the spinning and the appropriate temperature range plays an important role in the process of spinning. With supplemental heating means and infrared thermometer measurement ensure a stable temperature. Multi-passing thermal spinning Ti-6Al-4V alloy thins the billet thickness, using the feature obtaining the wanting complex shape shell of thick bottom and thin mouth. The spinning track, the number of spinning pass, feed rate affect the billet thinning. During thermal spinning process Ti-6Al-4V alloy rebound severe. The size reduction and feed have impact on the rebound. By modifying the spinning parameters and the mandrel repair to ensure the dimensional accuracy of workpiece. Spinning workpiece has fine grain and high strength.
