Experimental Investigation of Maximum Achievable Convolution Height of Metallic Bellows in Hydroforming Process

Subject Areas : metal forming

Mehdi  Safari ¹ (Department of Mechanical Engineering, Arak University of Technology)
Younes  Ghadiri ² (Department of Mechanical Engineering, Arak University of Technology, Iran)

Received: 2017-12-18 Accepted : 2018-05-09 Published : 2018-06-01

Keywords: Metallic bellows, Hydroforming process, Convolution height,

Abstract :

The manufacturing of metal bellows with high ratios of crown-to-root diameters is very sensitive to design parameters such as internal pressure inside the tube, axial force and movement, die-stroke length (distance of the dies) as well as the initial tube length. In this paper, hydroforming process of a metallic bellows is investigated experimentally. For this purpose, the effects of internal pressure and die stroke on the maximum achievable convolution height and thickness distribution of hydroformed bellows is studied. The experiments are performed with different internal pressures such as 90, 110 and 130 bars and also in different die strokes such as 10, 12 and 14 mm. The results show that by increasing the die stroke, the range of allowable internal pressure to produce a metallic bellows without wrinkling or bursting decreases and manufacturing of the bellows becomes more difficult. It is extracted from results that with holding the die stroke value, very low internal pressures leads to wrinkling in the hydroformed bellows while very high internal pressures cause the excessive thinning. Also, it is concluded that by increasing both internal pressure and die stroke the convolution height of manufactured bellows is increased. It is proved that the maximum thickness reduction is occurred at the crown point of hydroformed bellows.

References:

[1]     Je, G., Malka, D., Kim, H., Hong, S. and Shin, B., A Study on Micro Hydroforming Using Shock Wave of 355 nm UV-Pulsed Laser, Applied Surface Science, Vol. 417, 2017, pp. 244-249, DOI: https://doi.org/10.1016/j.apsusc.2017.02.146.

[2]     Kim, H. S., Sumption, M. D., Bong, H. J., Lim, H. and Collings, E. W., Development of a Multi-Scale Simulation Model of Tube Hydroforming for Superconducting RF Cavities, Materials Science and Engineering A, Vol. 679, 2017, pp. 104-115, DOI: https://doi.org/10.1016/j.msea.2016.10.022.

[3]     Hajializad, F., Mashhadi, M. M., Investigation and Numerical Analysis of Impulsive Hydroforming of Aluminum 6061-T6 Tube, Journal of Manufacturing Processes, Vol. 20, No. 1,  2015, pp. 257-273, DOI: https://doi.org/10.1016/j.jmapro.2015.06.027 .

[4]     Ziaei Poor, H., Moosavi, H., Menghari, H. G. and Sousa, R. A., Investigation of Punch Nose Radius and Punch-Die Clearance on Thinning and Puckering in Hydro-Mechanical Deep Drawing Process, International Journal of Mechanical Systems Engineering, Vol. 4, No. 2, 2014, pp. 16-21, DOI: http://dx.doi.org/10.15344/2455-7412/2015/101.

[5]     Bihamta, R., D’Amours, G. D., Bui, Q. H., Guillot, M., Rahem, A. and Fafard, M., Numerical and Experimental Studies on the New Design Concept of Hydroforming Dies for Complex Tubes, Materials and Design, Vol. 47, 2013, pp. 766-778, DOI: https://doi.org/10.1016/j.matdes.2012.12.075.

[6]     Li, Sh., Chen, X., Kong, Q., Yu, Zh. and Lin, Zh., Study on Formability of Tube Hydroforming Through Elliptical Die Inserts, Journal of Materials Processing Technology, Vol. 212, No. 9, 2012, pp. 1916-1924, DOI: https://doi.org/10.1016/ j.jmatprotec.2012.04.016.

[7]     Xu, X., Li, S., Zhang, W. and Lin, Z., Analysis of Thickness Distribution of Square-Sectional Hydroformed Parts, Journal of Materials Processing Technology, Vol. 209, No. 1, 2009, pp. 158-164, DOI: https://doi.org/10.1016/j.jmatprotec.2008.01. 034.

[8]     Hwang, Y. M., Chen, W. C., Analysis of Tube Hydroforming in a Square Cross-Sectional Die, International Journal of Plasticity, Vol. 21, No. 9, 2005, pp. 1815-1833, DOI: https://doi.org/10.1016/j.ijplas.2004.09.004.

[9]     Kridli, G. T., Bao, L., Mallick, P. K. and Tian, Y., Investigation of Thickness Variation and Corner Filling in Tube Hydroforming, Journal of Materials Processing Technology, Vol. 133, No. 3, 2003, pp. 287-296, DOI: https://doi.org/10.1016/S0924-0136(02)01004-X.

[10]  Wang, G., Zhang, K. F., Wu, D. Z., Wang, J. Z. and Yu, Y. D., Superplastic Forming of Bellows Expansion Joints Made of Titanium Alloys, Journal of Materials Processing Technology, Vol. 178, No. 1-3, 2006, pp. 24-28, DOI: https://doi.org/ 10.1016/j.jmatprotec.2005.10.005.

[11]              Lee, S. W., Study on the Forming Parameters of the Metal Bellows, Journal of Materials Processing Technology, Vol. 130-131, 2002, pp. 47–53, DOI: https://doi.org/10.1016/ S0924-0136(02)00787-2.