Magnetic pulse welding of thin walled ferritic martensitic steel T91 tube to T91 rod

Advanced Ferritic-Martensitic steels are candidate materials for fuel pin of next generation fast breeder reactors. Magnetic Pulse Welding (MPW) is a solid-state welding technology that uses electromagnetic pressure to join materials. It creates solid state joint, resulting from impact of job pieces at higher velocities. In this process the joining of metallic job pieces takes place at their boundary surfaces. Single turn tool coil with copper insert field concentrator is used to generate 52 T magnetic field with 830 kA pulse discharge current from 208 µF capacitor bank charged at 21 kV. T91 tube of 6.6 mm diameter and 0.45 mm thickness, placed inside the single turn tool coil is accelerated by pulse magnetic field, produced by discharge current of capacitor bank to impacts with T91 rod. The strong weld joint is obtained by sudden plastic deformation caused by electromagnetic pressure in microsecond’s duration. In this article, MPW of thin walled T91 tube toT91 rod with single turn tool coil is discussed along with the characterization of weld joint with helium leak test, weld interface analysis and micro hardness testing.