Grain Size Effect on Saddle Phenomenon in V-Bending Process of Thin Sheet Metal

Abstract:

The ability for predicting the springback on sheet metal bending processes is identified as an important feature of the ability for predicting the final geometry of sheet metal parts. The grain size effect makes the difficult on application of traditional design method in processing. As through tool and processing design, to understand the effects of grain size effects is an important and powerful way to effectively compensate for and eliminate the springback. In this paper, 99.5% pure iron specimens were annealed at different temperature to obtain the specified grain sizes. The effects of different grain sizes on the saddle after V-bending of the thin sheet metal were investigated. The results show that at the same thickness of specimens, the grain size has no significant effect on the saddle height. However, with increasing the thickness of the specimens the saddle will also be more prominent protruding height. The concave side of bent specimen is against the compression force and its grains structure tend to a round shape, whereas the convex side is against the tensile force and its grains structure tend to a flaky shape.

• Periodical: Key Engineering Materials (Volume 773)
• Pages: 202-207
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.773.202
• Online since: July 2018
• Authors: Chang Cheng Chen*, Yi Xiang Hong
• Keywords: Bending Process, Grain Size Effect, Thin Sheet Metal

References

[1] Z. Tekiner, An Experimental Study on the Examination of Springback of Sheet Metals with Several Thicknesses and Properties in Bending Dies, J. Mater. Proc. Tech. 145 (2004) 109–117.

DOI: 10.1016/j.jmatprotec.2003.07.005

[2] J. W. Hu, Response of Seismically Isolated Steel Frame Buildings with Sustainable Lead-Rubber Bearing (LRB) Isolator Devices Subjected to Near-Fault (NF) Ground Motions. Sustain. 7 (2015) 111-137.

DOI: 10.3390/su7010111

[3] M. L. Garcia-Romeu, J. Ciurana, I. Ferrer, Springback Determination of Sheet Metals in an Air Bending Process based on an Experimental Work, J. Mater. Proc. Tech. 191 (2007) 174–177.

DOI: 10.1016/j.jmatprotec.2007.03.019

[4] L. R. Sanchez, Modeling of Springback, Strain Rate and Bauschinger Effects for Two-dimensional Steady State Cyclic Flow of Sheet Metal Subjected to Bending under Tension, Int. J. Mech. Sci. 52 (2010) 429–439.

DOI: 10.1016/j.ijmecsci.2009.11.002

[5] J. W. Seo, Y. C. Kim, J. W. Hu, Pilot Study for Investigating the Cyclic Behavior of Slit Damper Systems with Recentering Shape Memory Alloy (SMA) Bending Bars Used for Seismic Restrainers, Appl. Sci. 5(3) (2015) 187-208.

DOI: 10.3390/app5030187

[6] M. C. Tsai, Y. A. Chen, C. F. Wu, F. K. Chen, Size-Effects in Micro-Metal Sheet Forming of Unalloyed Copper and Brass, Adv. Mater. Res. 6-8 (2005) 705-712.

[7] F. K. Chen, J. W. Tsai, A study of size effect in micro-forming with micro-hardness tests, J. Mater. Proc. Tech. 177 (2006) 146-149.

DOI: 10.1016/j.jmatprotec.2006.04.115

[8] T. Fülöp, W. A. M. Brekelmans, M. G. D. Geers, Size effects from grain statistics in ultra- thin metal sheets, J. Mater. Proc. Tech. 174 (2006) 233-238.

DOI: 10.1016/j.jmatprotec.2006.01.006