Electric slag welding is a fundamentally new method of permanently joining metals. It has been developed and put to practical use by the Paton Electric Welding Institute of the Ukrainian Academy of Sciences in collaboration with the Engineering Works at Novo-Kramatorsk and the Krasny Kotelshchik Boiler- Making Factory at Taganrog, both of which are leading plants in the field.As distinct from other fusion welding methods, the electric slag process depends on the lioaL generated by the passage of an electric current from the weld­ ing rod (electrode) to the workpiece through the molten pool of a high-resistance conductive flux, or slag. Hence its name—electric slag process.Submerged arc welding has proved less efficient on thicknesses over 50 or 60 mm than on lighter sections. This is because of the difficulty and, at limes, impossibility of making well-shaped welds with strong arcs in the downhand po­ sition in a single pass. Therefore, heavy-gauge plate has to be bevelled prior to welding and welded in many passes—which is out of pace with modern heavy engineering practice.Electric slag welding is a big step forward, as this process, coupled with weld moulding, has rendered possible the single-pass welding of plate of practically unlimited thickness.The electric slag process will inevitably bring about sweeping changes in tho fabrication of large-size structures, unique machines, heavy presses, large shafts, etc. With electric slag welding, all-cast and forged parts may be replaced with cast-welded, forged-welded, and rollcd-welded parts, thus reducing the burden on the foundries and forging shops of engineering works and stepping up produc­ tion without having to expand floor space.Electric slag welding has opened up new possibilities for the manufacture of composite and compound metals, automatic hard-facing and repair.In recent years, further headway has been made in the science and art of elec­tric slag welding, which has found many applications in heavy engineering and many other industries.With Soviet help, the electric slag process is now being employed in Czecho­slovakia, the German Democratic Republic, Poland and People’s China.Equipment for electric slag welding evoked keen interest at the World Fair in Brussels in 1958, where the electric slag process won a Grand Prix, and at Soviet exhibitions in New York, Marseille and Helsinki in 1959. Licences for the process and equipment have been bought by the ESAB of Sweden.The obvious advantages, both technical and economic, that the electric slag process possesses in comparison with other methods and processes of fusion welding of heavy sections have appealed to welding people in some Western countries. In 1959, equipment for electric slag welding went into production in Britain and West Germany.Recently, new modifications of the process have been developed—welding with large-size electrodes, welding with consumable electrode guides, and resist­ ance slag welding. Electric slag processes have found applications in metal making—for resmelting alloy steels and alloys, burning oil risers and gates from odd­ shaped castings, and repair of ingots.Furthermore, new data have been obtained as to the heat and metallurgical phenomena accompanying electric slag welding, primary crystallisation in the weld pool, and the strength of electric slag welds. Welding procedures have been developed for bi£h-alloy steels and alloys, titanium alloys, non-ferrous metals, and cast iron, and pul to commercial use. Electric slag welding techniques have been perfected to include straight butt-weld seams in sections up to two metres thick and circumferential seams on vessels and shafts with a wall thickness ofup to 400 mm.In 1057 the electric slag process earned its inventors—people working at the Electric Welding Institute and in industry—a Lenin Prize.In this book, the authors have sought to cover all the latest achievements in the science and art of electric slag welding.