Three-dimensional upper bound analyses for extrusion from square billets through complex die-openings' shapes

• Autorzy: Ajiboye J. S.

Warianty tytułu

PL

Analiza procesu wyciskania w matrycach o różnych kształtach z wykorzystaniem trójwymiarowej metody górnej oceny

• Języki publikacji: EN

Abstrakty

EN

A numerical model based on the upper bound elemental technique for prediction of extrusion pressure in three-dimensional direct extrusion process is presented. Using square billets, the study of the effect of die land length has been extended to the evaluations of the extrusion pressures to extrude complex sections such as square, rectangular, I, and T shaped sections with power of deformation due to ironing effect at the die land taken into account. The extrusion pressure contributions due to the die land evaluated theoretically for shaped sections considered are found to increase with die land lengths for any given percentage reduction and also increase with increasing percentage die reductions at any given die land length. The effect of die land lengths on the extrusion pressures increase with increasing complexity of die openings geometry with I-shaped section giving the highest extrusion pressure followed by T-shaped section, rectangular, circular shaped die openings with square section die opening, giving the least extrusion pressure for any given die reduction at any given die land length. The proper choice of die land length is, therefore, imperative if excessive pressure buildup at the emergent section is to be avoided so as to maintain the quality and metallurgical structure of the product. Comparison of the least upper bounds extrusion pressures computed with the experimental results and SERR analysis shows that the up-per bound method predicts reasonable extrusion loads well within engineering accuracy.

PL

W niniejszej pracy zaprezentowano możliwości przewidywania zmian pola ciśnień podczas wyciskania współbieżnego z wykorzystaniem metody górnej oceny. Analizie poddano wpływ kształtu matrycy z uwzględnieniem stopnia docisku na ewolucje pola ciśnień podczas wyciskania profili o złożonych przekrojach: kwadratowym, prostokątnym, I oraz T. Badania profili wykazały, że wkład ciśnienia generowanego podczas przejścia przez oczko matrycy zwiększa się wraz ze zwiększeniem się długości oczka dla danego stopnia redukcji przekroju, jak również zwiększa się wraz ze zwiększeniem się stopnia przekroju dla danej długości oczka matrycy. Wpływ długości oczka matrycy na ciśnienie zwiesza się również wraz ze wzrostem skomplikowania przekroju wyrobu. Najwyższy wpływ zaobserwowano dla przekroju typu I a następnie T, prostokątnego oraz kwadratowego. Analiza wyników wykazała istotność doboru kształtu matrycy na osiągniecie wymaganej jakości oraz struktury

Słowa kluczowe

EN

extrusion pressures; die land; shaped sections; % reduction in area; area ratio; upper bound

• Wydawca: Wydawnictwa AGH
• Czasopismo: Computer Methods in Materials Science
• Rocznik: 2008
• Tom: Vol. 8, No. 4
• Strony: 171--178
• Opis fizyczny: Bibliogr. 19 poz., rys.

Twórcy

autor

Ajiboye J. S.

• Department of Mechanical Engineering, University of Lagos, Lagos, Nigeria; present address: KAIST Valufacture Institute of Mechanical Engineering, School of Mechanical, Aerospace & Systems Engineering, Korea Advanced Institute of Science and Technology,

Bibliografia

• Abrinia, K., Makaremi, M., 2008, A new three-dimensional solution for the extrusion of sections with larger dimensions than the initial, J. Mat. Proc. Techn., 205, 1-3, 259-271.
• Ajiboye, J.S., 2006, Extrusion Pressure and Temperature changes during forward Extrusion Process, PhD thesis, University of Ilorin, Nigeria.
• Ajiboye, J.S., Adeyemi, M.B., 2006, Effects of Die land on the cold extrusion of lead alloy, J. Mat. Proc. Techn., 171, 428-436.
• Chitkara, N.R, Adeyemi, M.B., 1977, Working pressure and deformation modes in forward extrusion of I and T shaped sections from sąuare slugs, Proc. 18th Int. MTDR Co/7/, Imperiał College of Science and Tech., London, 289-301.
• Chitkara, N.R., Celik, K.F., 2001, Extrusion of non-symmetric T-shaped sections an analysis and some experiments, Int. J. Mech. Sci, 43, 2961-2987.
• Duan, X., Yelay, X., Sheppard, T., 2004, Application of finite element method in the hot extrusion of aluminum alloys, Mat. Sci. Eng. A, 369, 1-2, 66-75.
• Pilice, L., Alfaro, L, Gagliardi, F., Cueto, E., Micari, F., Chinesta, F., 2008, A preliminary comparison between finite element and meshless simulations of extrusion, J. Mat. Proc. Techn., in Press, Corrected Proof, Available online 18 July 2008.
• Kar, P.K., Das, N.S., 1997, Upper bound analysis of extrusion of I-section bars from sąuare/rectangular billets through sąuare dies, Int. J. Mech. Sci, 39, 925-934.
• Kim, Y.H., Park, J.H., Jin, Y.E., 1999, An analysis of plastic deformation processes for twist-assisted upset forging of cylindrical billets, Proc. Int. Conf. on Advances in Materials and Processing Technologies (AMPT'99) and 16th Annual Conference of the Irish Manufacturing Committee(IMC16), 1,79-86.
• Kim, Y.H., Park, J.H., Jin, Y.E., Lee, Y., 2000, An analysis of the torsional forming process using the dual stream func-tion, Proc. 8th Int. Conf. Metal Forming, eds, Pietrzyk, M., Kusiak, J., Majta, J., Hartley, P., Pillinger, L, A. Balkema, 741-746.
• Kiuchi, M., Kish, H., Ishikawa M., 1981, Study on Non symmetric extrusion and drawing, Int. Journal Mach. Tool, Proc. 22nd Conf. Design and Research, 523-532.
• Kiuchi, M., Yanagimoto, J., Mendoza, V., 1996, Characterization of three-dimensional metal flow in extrusion proc­ess, CIRP Annals - Manufacturing Technology, 45, l, 235-238.
• Li, G., Jinn, J.T, Wu, W.T., Oh, S.I., 2001, Recent development and applications of three-dimensional finite element modeling in bulk forming processes, J. Mat. Proc. Techn., 113, 1-3,40-45.
• Nanhai et al., 2000, Numerical design of die land for shape extrusion, J. Mat. Proc. Techn., 101, 81-84.
• Sheppard, T., Paterson, S.J., 1982, Some observations on metal flow and the development of structure during the direct and indirect extrusion of commercial purity aluminum, J. Mech. Work. Techn., 7, l, 39-56.
• Sahoo, S.K., Kar, P.K., 2000, Round-to-hexagon drawing through straightly converging dies: an application of the SERR technique, Int. J. Mech. Sci., 42, 445-449.
• Yenkata Reddy, N., Dixit, P. M., Lal, G.K., 1995, Die design for axisymmetric extrusion, J. Mat. Proc. Techn., 55, 3-4, 331-339.
• Wu, C.W, Hsu, R.Q., 2000, Theoretical analysis of extrusion of rectangular, hexagonal and octagonal composite clad rods, Int. J. Mech. Sci, 42, 473-486.
• Yang, D.Y, Lee, H.S., 1993, Analysis of Three-Dimensional Deep Drawing by the Energy Method, Int. J. Mech. Sci., 35,491-516.