The removal of nonmetallic inclusions and gases from nickel-based alloys in electron beam melting with an intermediate crucible

摘要

The main process of production of high-quality ingots of nickel-based alloys in industry is steel vacuum-arc melting with a consumable electrode (VAR). In the case of creep-resisting alloys based on nickel, this problem is solved using the duplex process: the electrodes for VAR are produced by vacuum-induction melting. Recently, the production of ingots of nickel-based alloys has been carried out using alternative methods of melting based on the processes with an independent heating source such as electron bream and plasma are processes. The interest n these processes is caused in particular by the increased requirements on the quality of metal from the side of the users of the products of aerospace applications [1]. Melting in electron beam furnaces with an intermediate crucible satisfies most efficiently the requirements of production of defect-free ingots of nickel alloys. This advantage of electron beam remelting is based on the presence of a concentrated heat source which makes it possible to change in a wide range of the temperature of liquid metal and also carry out melting with pouring of metal and conduct controlled solidification of the molten metal in a solidification mould. The processes of refining electron beam melting in an intermediate crucible take place in three stages: at the end of the molten blank, in the intermediate container and in the solidification mould. This decreases the content of gases and nonmetallic inclusions [1].