The objective of this paper is to propose a friction test method to evaluate the performance of different kinds of lubricants and determine their coefficients of friction in tube hydroforming processes. A self-designed apparatus is used to conduct the experiments of friction tests. The coefficient of friction between the tube and the die at the guiding zone is determined. The effects of the internal pressure and the axial feeding velocity on the friction forces and coefficients of friction for various lubricants are discussed. From the experimental results, it is known that MoS2 corresponding to a coefficient of friction of 0.018 is the best lubricant among the evaluated lubricants during tube hydroforming processes.
SokolowskiT.GerkeK.AhmetogluM.AltanT.Evaluation of tube formability and material characteristics: Hydraulic bulge testing of tubes. J. Mater. Processing Technol, 2000, 98, 34–40.
2.
AhmetogluM.AltanT.Tube hydroforming: State-of-the-art and future trends. J. Mater. Processing Technol., 2000, 98, 25–33.
3.
DohmannF.HartlCh.Tube hydroforming: Research and practical application. J. Mater. Processing Technol., 1997, 71, 174–186.
4.
DohmannF.HardCh.Hydroforming - a method to manufacture light-weight parts. J. Mater. Processing Technol., 1996, 60, 669–676.
5.
AsnafiN.Analytical modeling of tube hydroforming. Thin-walled Structs, 1999, 34, 295–330.
6.
AsnafiN.SkogsgardhA.Theoretical and experimental analysis of stroke-controlled tube hydroforming. Mater. Sci. Engng, 2000, A279, 95–110.
7.
HwangY. M.ChenW. C.Analysis and finite element simulation of tube expansion in a rectangular cross-sectional die. Proc. Instn Mech. Engrs, Part B: J. Engineering Manufacture, 2003, 217, 127–135.
8.
HwangY. M.AltanT.Process fusion: Tube hydro-forming and crushing in a square die. Proc. Instn Mech. Engrs, Part B: J. Engineering Manufacture, 2004, 218, 169–174.
HwangY. M.LinY. K.Analysis and finite element simulation of the tube bulge hydroforming process. J. Mater. Processing Technol., 2002, 125-126, 821–825.
11.
HwangY. M.AltanT.Finite element analysis on tube hydroforming processes in a rectangular die. Finite Elements in Analysis Des., 2003, 39, 1071–1082.
12.
NgaileG.JaegerS.AltanT.Lubrication in tube hydroforming (THF): Part I. Lubrication mechanisms and development of model tests to evaluate lubricants and die coatings in the transition and expansion zones. J. Mater. Processing Technol., 2004, 146, 108–115.
13.
NgaileG.JaegerS.AltanT.Lubrication in tube hydroforming (THF): Part II. Performance evaluation of lubricants using LDH test and pear-shaped tube expansion test. J. Mater. Processing Technol., 2004, 146, 116–123.
14.
VollertsenF.PlancakM.On possibilities for the determination of the coefficient of friction in hydroforming of tubes. J. Mater. Processing Technol., 2002, 125-126, 412–420.
15.
GrocheP.PeterA.Performance of lubricants in internal high pressure forming of tubes. In Proceedings of the 7th International Conference on the Technology of Plasticity, October 2002, Yokohama, Japan, Advanced Technology of Plasticity, Vol. 2.
16.
HwangY. M.LinY. K.LinJ. C.Study on forming limit of tubular materials. Key Engng Mater., 2004, 274-276, 391–396.
