Technology for the Production of High-Melting-Point Metal Master Alloys and their Testing in the Melting of Foundry Heat-Resistant Nickel Alloys

This paper presents the technology of producing, in vacuum arc furnaces, master alloys based on nickel and rare refractory metals (rhenium, ruthenium, and hafnium) of ReNi-1, RuNi-2, and HfNi10 grades. The technology involves the use of metal powders as initial components, which are pre-compressed into tablets and degassed in a vacuum electric resistance furnace. Though this process, an ultra-low content of gas impurities in the master alloys is provided, which increased their manufacturability when introduced into the melt and contributed to the quality improvement of the smelted cast heat-resistant nickel alloys. Alloys ZhS32, VZhM4, and VKNA-1VR, melted using the developed master alloys, have high chemical composition stability, low levels of harmful impurities and gases, and consistently high levels of mechanical properties, which comply with the requirements of technical specifications and alloy certificates.