Abstract: Two coaxially aligned workpieces of ferromagnetic material, axially separated by a narrow peripheral gap across which a weld seam is to be formed with the aid of an arc moving along that gap, are engaged by holders including at least one set of two or more ferromagnetic gripper jaws whose confronting faces are magnetized with like polarity by respective excitation windings surrounding extensions of these jaws. The resulting magnetic field extends axially within the workpiece held by the gripper jaws in a loop which passes generally radially through the peripheral gap, either on account of a bucking magnetic field (which may be generated by a similar set of jaws gripping the other workpiece) or by virtue of pole shoes of the opposite polarity juxtaposed with the jaw extensions and approaching the gap.

Abstract: An electrical arc welding device for two workpieces to be welded together along an annular weld seam, e.g. ends of pipe sections, and in which a magnet arrangement surrounds the welding-seam path. According to the invention, a magnetizable ring is formed by the inwardly extending poles of a plurality of magnets having flat cores and surrounded by coils for electromagnetically energizing the cores.

Abstract: A pair of workpieces are welded together by passing between them an arc which is guided by a magnetic field to rotate on the workpieces. Immediately after striking of the arc the field strength of the magnetic field is relatively great and a relatively great current is similarly passed through the arc. During a subsequent main phase, before fusing of the surfaces to be welded, the field strength and the current of the arc are reduced to a fraction of their values for even heating of the surfaces to be welded together. Finally during a terminal phase the current of the arc and the field strength are again raised to a higher level to completely fuse the two surfaces which can then be welded together once the arc is interrupted.

Abstract: A device for welding two metallic hollow bodies together in end-to-end connection by means of an electric arc moved by the effect of an external magnetic field along the welding joint, comprises, clamping means engaged with the bodies to clamp them in end-to-end relationship with the respective ends to be joined disposed closely adjacent. In addition, a magnetic coil is disposed within at least one of the bodies or it is advantageously located with a pole piece disposed in the gap between the two bodies and overlapping each of the bodies so as to produce a magnetic field in the vicinity of the ends to be joined. The pole shoe of the magnet advantageously comprises a pole piece which is conformable to the dimensions of the shape of the welded joint.