Effect of Counter Punch Pressure on Springback of High Strength Steel Sheet

Abstract:

To reduce springback in U-bending the present paper proposes a new technique where the bottom of a U-bent part is clamped between a punch and a counter-punch during bending and it is pushed up with the counter punch at the final stage. The effect of counter punch pressure, both in sheet clamping and bottoming, was investigated by performing experiments on dual phase 590MPa and TRIP 780MPa HSS sheets. From the experiment, an appropriate combination of the clamping force and the final pushing-up force was found where springback was reduced to almost zero. To investigate the mechanism of the reduction of springback in the above three-step U-bending process, FE simulation of the bending with PAM-STAMP 2G was also conducted where the advanced kinematic hardening Yoshida-Uemori model was employed.

• Periodical: Advanced Materials Research (Volume 939)
• Pages: 305-312
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.939.305
• Online since: May 2014
• Authors: Komgrit Lawanwong*, Hiroshi Hamasaki, Ryutaro Hino, Fusahito Yoshida
• Keywords: Counter Punch, High Strength Steel Sheet, Springback, U-Bending

References

[1] K. Lange, Handbook of Metal Forming, New York: McGraw-HillInc, (1985).

[2] P. Chen, M. Koc, Simulation of spring back variation in forming of advanced high strength steels, J. Mater. Process. Technol. 190, (2007) 189–198.

[3] K. Mori, K. Akita, Y. Abe, Springback behaviour in bending of ultra-high-strength steel sheets using CNC servo press, Int. J. Mach. Tool. Manuf. 47, (2007) 321-325.

DOI: 10.1016/j.ijmachtools.2006.03.013

[4] Y. Nagai, AccurateU-bending of sheets, J. JPN. Soc. Technol. 29-234, (1988) 69-74.

[5] T. Yamano, J. Iwaya, Study of countermeasure of side wall curl using overrun-inducing punch, J. JPN. Soc. Technol. 46-534, (2005) 630-635.

[6] T. Ogawa, F. Yoshida, Springback analysis on U-bending with bottoming, in: K. Chung (Ed. ), Proceedings of the 8th International Conference and Workshop on Numerical Simulation of 3D Sheet Metal Forming Processes (NUMISHEET), 2011, p.1129–1136.

[7] F. Yoshida, T. Uemori, A model of large-strain cyclic plasticity describing the Bauschinger effect and work hardening stagnation, Int. J. Plast. (2002) 661– 686.

DOI: 10.1016/s0749-6419(01)00050-x

[8] F. Yoshida, T. Uemori, K. Fujiwara, Elastic–plastic behavior of steel sheets under in-plane cyclic tension-compression at large strain, Int. J. Plast. 18, (2002) 633–659.

DOI: 10.1016/s0749-6419(01)00049-3

[9] F. Yoshida, T. Uemori, A model of large-strain cyclic plasticity and its application to springback simulation, Int J. Mech. Sci. 45, (2003) 1687–1702.

DOI: 10.1016/j.ijmecsci.2003.10.013

[10] K. Yilamua, R. Hinob, H. Hamasakib, F. Yoshida, Air bending and springback of stainless steel clad aluminum sheet, J. Mater. Process. Technol. 210, (2010) 272–278.

DOI: 10.1016/j.jmatprotec.2009.09.010

[11] P. A. Eggertsen, K. Mattiasson, On constitutive modeling for springback analysis, Int J. Mech. Sci. 52, (2010) 804-812.