Abstract: Hollow magnetic pipe having a magnetic field extending across the hollow of the pipe is prepared by a multistep process which includes (a) forming first and second pipe halves from ductile and magnetizable sheet metal, (b) placing the pipe halves in pipelike alignment and joining each pair of adjacently disposed, opened edges thereof with a nonmagnetic seam to form a hollow pipe, (c) conditioning the hollow pipe to receive and maintain a permanent magnetic state, and (d) subjecting the conditioned hollow pipe to a magnetic field whereby the side walls abutting one nonmagnetic seam acquire a permanent north magnetic pole configuration and the side walls abutting the other nonmagnetic seam acquire a permanent south magnetic pole configuration. The hollow magnetic pipe is adapted for use as a conduit for conveying conductive fluid in magnetohydrodynamic energy amplification systems.