Study for Frictional Characteristics of graphite lubricants in hot. warm forging

열ㆍ온간 단조에서 그라파이트 윤활제의 마찰 특성에 대한 연구

  • ;
  • ;
  • T.A. Dean (IRC, University of Birmingham, UK)
  • 김동진 (부산대학교 기계설계공학과) ;
  • 김병민 (부산대학교 정밀정형 및 금형가공 연구센) ;
  • Published : 2000.04.01

Abstract

At present there are many theories as to how various lubricants used in forging perform the role of reducing friction. Little work has been carried out to determine the validity of these theories for solid lubricants. This paper covers the development and preliminary results of the experiments devised to illustrate the movement of graphite at the workpiece/tool interface in the work forging temperature range. The paper describes the results obtained from upsetting of rings between two flat dies for measurement of lubricant thickness and compaction of graphite for density-pressure relationship. These allowed the lubricant to be exposed to forging conditions and by applying the principles of Male's ring test the simple generation of a value fur friction factor could also be determined. The experiments have been undertaken to examine the behavior of lubricant for shot blasted surface and change of surface roughness. A simple computer model of the interface has been constructed characterizing the graphite layer in an attempt to simulate the boundary mechanics.

Keywords

References

  1. T. Altan, S. Oh, H. Gegel, 'Metal forming,' ASM, Metal Park, PH44073, 1983
  2. J. A. Schey, 'Metal deformation processes : Friction and lubrication,' Marcel Dekker, New York, 1970
  3. T. Altan, 'Heat generation and temperatures in wire ad rod drawing,' Wire Journal, March 1970
  4. T. Altan, P. Miller, 'Design for forming and other near net shape manufacturing processes,' CIRP, Vol. 2, pp. 609-620, 1990
  5. F. Bowden, D. Tabor, 'The friction and Iubrication of solids,' Oxford Clarendon Press, 1953
  6. J. Schey, 'Tribology in metal working,' ASM, Metal Park, Ohio, 1983
  7. G. Rooyen, W. Backofen, 'A study of interface friction in plastic compression,' Int. J. Mech. Sci., Vol1, pp. 1-27, 1960 https://doi.org/10.1016/0020-7403(60)90027-8
  8. M. Nanneh, F. Dunne, 'The role of inhomogeneous deformation in high-temperature ring compression testing,' Proc. Instn. Mech. Engers. Vol.211, Part B, pp. 215-222, 1997 https://doi.org/10.1243/0954405971516202
  9. A. Behrens, H. Schafstall, '2D and 3D simulation of complex multistage forging processes by use of adaptive friction coefficent,' J.Mat. Proc. Tech. Vol. 80-81, pp. 298-303, 1998
  10. A. Azushima, S. Yoneyama, T. Yamaguchi, H. Kudo, 'Direct observation of microcontact behavior at the interface between tool and workpiece in lubricated upsetting,' CIRP, Vol. 45, No. 1, pp. 205-210, 1996 https://doi.org/10.1016/S0007-8506(07)63048-
  11. F. Wang, J. Lenard, 'An experimental study of interfacial friction-hot ring compression,' J. Eng. Mat Tech. Vol. 114, pp. 13-18, 1992
  12. N. Rudkins, P. Hartley, I. Pillinger, D. Petty, 'Friction modeling and experimental observations in hot ring compression tests,' J. Mat. Proc. Tech., Vol. 60, pp. 349-353, 1996 https://doi.org/10.1016/0924-0136(96)02353-9
  13. A. de Sanctis, A. Forcellese, S. Roberts, P. Withers, 'Frictional behaviour of A1359/Sic20p composite under isothermal and non-isothermal hot-working conditions as a function of surface roughness,' J. Mat. Proc. Tech., Vol. 72, pp. 195-200, 1997 https://doi.org/10.1016/S0924-0136(97)00165-9
  14. R. Bunten, R. Hopp, 'Simulation of microscopic surface changes during metal friction and roughness phenomenons in metallic contact,' 19th IDDRG Biennial Congress, Eger, 10-14, pp. 315-324, 1996
  15. A. Landdown, 'High temperature lubrication,' Mech. Eng. Pub. Limited, 1994
  16. A. Male, M. Cockcroft, 'A method for the determination of the coefficient of friction of metals under conditions of bulk plastic deformation,' J. Inst. Metals, Vol. 93, p. 38, 1965