Accuracy Improvement of Upper Bound Analysis of Bimetallic Rods Extrusion Using a New Velocity Field

Subject Areas : Mechanical Engineering

Hamed  Afrasiab ¹ (Babol University of Technology)
Mojtaba  Qasemi-Mahallekolaei ² (Babol University of Technology)

Received: 2016-07-19 Accepted : 2016-10-23 Published : 2016-12-24

Keywords: Upper bound analysis, Direct extrusion, Bimetallic rods,

Abstract :

In this paper, the direct extrusion process of bimetallic rods in conical dies is analyzed by an improved upper bound method. The deformation zone is subdivided into six smaller zones and by considering a non-spherical entrance boundary to the deformation zone, a velocity field is presented which is different from velocity fields employed in previous studies. The total power consumption of the process including internal, shear and frictional powers is obtained using this velocity field, and then the forming force is calculated by employing the upper bound theory. The superior accuracy of the proposed analysis is demonstrated by comparing the computed force with available experimental data and results of an upper bound analysis in the literature. Finally, the developed model is employed to study the effect of some process parameters on the forming load. It is observed that there is an optimal die angle that minimizes the extrusion force. The value of this optimum angle increases with friction coefficient.

References:

[1]     Ahmed, N., “Extrusion of Copper Clad Aluminum Wire,” J. Mech. Work Tech., Vol. 2, 1978, pp. 19-32.

[2]     Berski, S., Dyja, H., Banaszek, G., and Janik, M., “Theoretical Analysis of Bimetallic Rod Extrusion Process in Double Reduction Die,” Journal of Materials Processing Technology, Vol. 154, 2004, pp. 583–588.

 

 

 

 

[3]     Osakada, K., Limb, M., and Mellor, P. B., “Hydrostatic Extrusion of Composite Rods with Hart Cores,” International Journal of Mechanical Sciences, Vol. 15, 1973, pp. 291-307.

[4]     Avitzure, B., Wu, R., Talbert, S., and Chou, Y. T., “Criterion for Prevention of Core Fracture During Extrusion of Bimetal Rods,” J. Eng. Ind., Vol. 104, 1982, pp. 293-304.

[5]     Avitzure, B., Wu, R., Talbert, S., and Chou, Y. T., “Analysis of Core Fracture in Drawing of Bimetal Rods and Wires,” J. Eng. Ind., Vol. 108, 1986, pp. 133-140.

[6]     Peng, D. S., “An Upper-Bound Analysis of the Geometric Shape of the Deformation Zone in Rod Extrusion,” Journal of Materials Processing Technology, Vol. 21, 1989, pp. 303-311.

[7]     Tokuno, H., and Ikeda, K., “Analysis of Deformation in Extrusion of ­composite rods,” Journal of Materials Processing Technology, Vol. 26, 1991, pp. 323-335.

[8]     Chitkara, N. R., Aleem, A., “Extrusion of Axi-Symmetric Bimetallic Tubes From Solid Circular Billets: Application of a Generalized Upper Bound Analysis and Some Experiments,” International Journal of Mechanical Sciences, Vol. 43, 2001, pp. 2833-2856.

[9]     Hwang, Y. M., and Hwang, T. F., “An Investigation into the Plastic Deformation Behavior With in a Conical Die During Composite Rod Extrusion,” J. Mater process Technol., Vol. 121, 2002, pp. 226-233.

[10]  Haghighat, H., Asgari, G. R., “A generalized Spherical Velocity Field for Bimetallic Tube Extrusion Through Dies of any Shape,” International Journal of Mechanical Sciences, Vol. 53, 2011, pp. 248-253.

[11]  Haghighat, H., Amjadian, P., “A Generalized Upper Bound Solution for Extrusion of Bi-Metallic Rectangular Cross-Section Bars Through Dies of any Shape,” Journal of Theoretical and Applied Mechanics, Vol. 51, 2013, pp. 105-116.

[12]  Haghighat, H., Mahdavi, M., “Upper Bound Analysis of Bimetallic Rod Extrusion Process Through Rotating Conical Dies,” Journal of Theoretical and Applied Mechanics, Vol. 51, 2013, pp. 627-637.

[13]  Haghighat, H., Mahdavi, M. M., “Analysis and FEM Simulation of Extrusion Process of Bimetal Tubes Through Rotating Conical Dies,” Transactions of Nonferrous Metals Society of China, Vol. 23, 2013, pp. 3392-3399.

[14]  Haghighat, H., Shayesteh, H., “Upper Bound Analysis for Hybrid Sheet Metals Extrusion Process Through Curved Dies,” Transactions of Nonferrous Metals Society of China, Vol. 24, 2014, pp. 3285–3292.

[15]  Prager, W., Hodge, P. G., “Theory of Perfectly Plastic Solids”, John Wiley and Sons Inc., New York, 1951.

[16]  Unckel, H. A., “Extrusion - Some Experimental Work on Hot Short Alloys,” Met. Ind., Vol. 49, 1946, pp. 429.

[17]  Kalpakjian, S., “Manufacturing Processes for Engineering Materials”, 5th ed., Addison-Wesley, Reading, 1984.