New technique of precision necking for long tubes with variable wall thickness

Abstract

This study analyzed the deformation law of rear axles with variable wall thickness under bidirectional horizontal extrusion and found that necking was accompanied by upsetting deformation through theoretical calculation, numerical simulation, and experimental research. The sequence and occurrence of necking and upsetting deformations were obtained. A theory of deformation was proposed by controlling the distribution of temperature field. Effective processes to control the wall thickness of rear axle at different positions were also proposed. The ultimate limit deformation with a necking coefficient of 0.68 could be achieved using the temperature gradient coefficient. A new technology of two-step heating and two-step extrusion for a 13 t rear axle was developed, qualified test samples were obtained, and suggestions for further industrial application were put forward.

Key words： extrusion; rear axle; necking coefficient; temperature gradient

Acknowledgements

This work was supported by the National High-tech R&D Programof China (Grant No. 2012AA040202).

References

1 Deng L, Wang X, Jin J, Precision forging technology for aluminum alloy. Frontiers of Mechanical Engineering, 2018, 13(1): 25–36

2 Yu H, Chen J, Liu W, Electromagnetic forming of aluminum circular tubes into square tubes: Experiment and numerical simulation. Journal of Manufacturing Processes, 2018, 31: 613–623

3 Takahashia Y, Kiharaa S, Nagamachib T. Effects of neck length on occurrence of cracking in tube spinning. Procedia Manufacturing, 2018, 15: 1200–1206

4 Kwiatkowski L, Tekkaya A E, Kleiner M. Fundamentals for controlling thickness and surface quality during dieless necking-in of tubes by spinning. CIRP Annals, 2013, 62(1): 299–302

5 Kumar Y, Kumar S. Experimental and analytical evaluation of incremental sheet hydro-forming strategies to produce high forming angle sheets. Heliyon, 2019, 5(6): e01801

6 Abdolvand H, Sohrabi H, Faraji G, A novel combined severe plastic deformation method for producing thin-walled ultrafine grained cylindrical tubes. Materials Letters, 2015, 143: 167–171

7 Ren Z, Huang X. Effect of gas flow rate on the double gas-assisted extrusion forming of plastic pipes. IOP Conference Series: Earth and Environmental Science, 2019, 267(4): 042059

8 Dong S R, Chen G G. Projectiles and Rockets Producing Technology. Beijing: Beijing Institute of Technology Press, 2014, 94–100 (in Chinese)

9 Xu C G, Ren G S, Guo Y Q. Tube necking extrusion principle and forming process of trailer rear axle. Procedia Engineering, 2014, 81: 634–640

10 Liu G H, Guo Y Q, Jiang Z. Influence of heating models on necking deformation during tube extrusion process. Advanced Materials Research, 2011, 189–193: 1778–1781

11 Avitzur B. Handbook of Metal-Forming Processes. New York: John Wiley & Sons, 1983, 480–481

12 Zhang Y, Xu C G, Guo Y Q, Constitutive equations of 20Mn2 seamless steel tube for trailer rear axle under warm and hot deformation. Journal of Plastic Engineering, 2015, 22(3): 32–37 (in Chinese)

13 Yu H Q, Chen J D. Metal Plastic Forming Principle. Beijing: China Machine Press, 1999, 200–203 (in Chinese)

14 Daouben E, Dubois A, Dubar M, Effects of lubricant and lubrication parameters on friction during hot steel forging. International Journal of Material Forming, 2008, 1(S1): 1223–1226

15 Weaver P M, Dickenson R. Interactive local/Euler buckling of composite cylindrical shells. Computers & Structures, 2003, 81(30–31): 2767–2773

16 Lin Z P. Mathematical solution of ring upsetting and its application. Forging & Stamping Technology, 1980, (6): 1–11 (in Chinese)

17 Lu Y. Study of preform and loading rate in the tube nosing process by spherical die. Computer Methods in Applied Mechanics and Engineering, 2005, 194(25–26): 2839–2858

18 Schlemmer K L, Osman F H. Differential heating forming of solid and bi-metallic hollow parts. Journal of Materials Processing Technology, 2005, 162–163: 564–569

19 Yoshihara S, Nishimura H, Yamamoto H, Formability enhancement in magnesium alloy stamping using a local heating and cooling technique: Circular cup deep drawing process. Journal of Materials Processing Technology, 2003, 142(3): 609–613