Review of methods of obtaining hollow bar by electroslag remelting. Part I

Brief overview of methods of obtaining hollow bars is presented. Interest to the potential of electroslag technologies in question of improving the quality of hollow bars is resumed in connection with the development of resource extraction industries and power engineering. The problem of increasing operational properties of hollow bars and reducing their cost is very important and requires further solving. The formation of a cavity by the method of hot deformation in production of hollow bars of the closed shape is a forced solution which was used by steelmakers because of the low quality of castings. Methods must be sought to obtain cast hollow bars having the quality not inferior to hot deformed ones. This problem is successfully solved based on electroslag remelting technologies. The application of electroslag remelting (ESR) for the production of hollow ingots was implemented in the E.O. Paton Electric Welding Institute of the NAS of Ukraine in the 1970s. Electroslag remelting is one of the most progressive ways to improve the structure and physico-chemical properties of metal through control of crystallization processes. The expediency of application of electroslag remelted hollow bars for the manufacture of equipment used in resource extraction industries and power engineering are shown. Advantages and disadvantages of the main types of ESR are presented, for example, the ones with movable mandrel, not movable reusable mandrel, movable mold and bars, centrifugal electroslag casting, liquid die forging in electroslag casting, electroslag composition and ESR extrusion.