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M. R. Kulkarni ¹, Satendra Kumar ¹, P. C. Saroj ¹, Tanmay Kolge ¹, A. Sharma ¹, S. Dond ²

Affiliations
1 Accelerator and Pulse Power Division Bhabha Atomic Research centre Mumbai - 400085, IN
2 Research Scholar, Homi Bhabha National Institute Mumbai - 400094, IN

Abstract

The Accelerator and Pulse Power Division (APPD), BARC has developed strong Bitter coil with field shaper and 70 kJ, 25 kV electromagnetic manufacturing machine, for forming and welding applications. They conducted investigations into possibility of using Electromagnetic Pulsed Technology (EMPT) in joining austenitic –austenitic stainless steels, using samples fabricated to simulate tube and caps with coil developed at laboratory. The coil has been designed for industrial mass production that consists of four numbers of copper discs axially reinforced with non-magnetic steel studs. The polyamide films are used as coil and stud liner whereas Fibre Reinforced Plastic (FRP) is used as inter disc insulation. This paper discusses the design details of the 20kV, 250kA, 10 kHz Bitter coil, field shaper with replaceable inserts. This designed coil has been regularly used at rated value and generating the field of 35-40T in volume of Ø8.8mmX13mm. The steel tube to plug joints developed by this tool qualified helium leak better than 1.2x10^-9 mBar.litre.s^-1 and parent tube failed under pull out test but joint was intact.

Keywords

Bitter coil, field shaper, magnetic welding, tool design

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S. K. Dond ¹, M. R. Kulkarni ², Archana Sharma ², G. K. Dey ²

Affiliations
1 Homi Bhabha National Institute.Anushaktinagar, Mumbai, Maharashtra 400094, IN
2 Bhabha Atomic Research Centre Trombay, Mumbai, Maharashtra 400085, IN

Abstract

Electromagnetic forming is a high velocity forming process where Lorentz force is used for workpiece expansion. The required velocity for forming is achieved by a pulsed magnetic field. In the present work, Electromagnetic expansions of aluminum tubes are carried out using 20 kJ systems at different energies. A 2D coupled numerical simulation is also performed that shows the tube velocity and deformation under transient magnetic pressure. From the observed results, magnetic to mechanical pressure relation is studied that helps in controlled forming operation.

Keywords

Electromagnetic forming, Magnetic pressure, Plastic deformation, Coupled simulation

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