Abstract: In a method of automatically welding rails, welding of bottom portions of the rails is carried out as root pass welding of a first layer according to CO.sub.2 gas shielded arc weld technique, and as continuous multilayer welding of layers above the first layer according to CO.sub.2 gas shielded arc weld technique without discontinuing the welding of a second layer and upper layers. In welding of ankle portions (R2) of the rails, a flux is rapidly added to promptly shift to electroslag weld. Then, welding is conducted to head surfaces (R5) of the rails by continuing electroslag weld technique. This automatic welding method enables high efficiency field welding of rails, obviating the need for any complicated switching operation of the electric power source and use of several kinds of welding materials.

Abstract: A process for automatic fusion welding of rails by a combination of submerged arc welding and electroslag welding, comprising a root run for welding a rail base by submerged arc welding and, without interruption of the welding, subsequent runs for welding the rail base and welding a region from a rail web to a rail head by electroslag welding; wherein, during all of the runs, a metal mold is mounted on an upper surface of the rail base and a metal shoe is mounted on the metal mold to prevent an outflow of molten slag and molten metal and, during all of the runs, welding is performed by using a DC welding transformer having constant potential characterisitcs, a filler-wire having a diameter of from 1.2 to 2.0 mm, and a fused-type flux. The inventive process avoids the use of different fluxes and an alteration of welding machine conditions during the whole sequence of welding from the rail base through to the rail head.

Abstract: In welding iron, steel, and nonferrous alloys, the wire feed is changed periodically and in synchronism with periodic changes of the electric welding current to establish a previously defined relation between the welding current value and the arc length. The welding current is varied between one producing a spray transfer arc and a current just maintaining the arc.