Hrechka O. Development of a heat-resistant alloy with improved physical-mechanical and operational properties for electric heaters

The dissertation is devoted to the solution of the actual scientific and practical task of developing a heat-resistant alloy with high electrical resistance of type 22Cr-5Al-Ti-Zr, which is used as a material for the manufacture of heaters of electric furnaces with a operating temperature of 900...1150ºС. A new system of multicomponent alloying and microalloying with titanium, zirconium and beryllium of an iron-chromium-aluminum alloy has been developed. The chemical composition has been optimized, regression equations are obtained, three-dimensional graphical dependencies of the properties (technological ductility and heat resistance) on the chemical composition of the Fe-Cr-Al alloy with titanium and zirconium are constructed. The effect of the recrystallization temperature on the technological ductility of the 03Cr22Al5TiZr alloy was investigated. A rational mode of heat treatment of steel has been developed. It consists in heating to 750...820°C followed by cooling into water to prevent a sharp decrease in ductility. It was found that the steam-plasma charge treatment has a positive effect on the surface of the wire made from alloys with high electrical resistance. A rational mode of treatment of the surface of the wire or strip with the use of steam-plasma charge for removal of surface defects, technological lubrication and oxide scale is suggested. The expediency of the conducted scientific and technical researches is confirmed by the use of the developed heat-resistant alloy 03Cr22Al5TiZr as a material for the manufacture of heating elements of electric resistance furnaces at Limited Liability Company «Zaporozhye Titanium & Magnesium Combine». Keywords: heating elements, heat-resistant alloys, superior resistance heating alloys, iron-chromium-aluminium (Fe-Cr-Al) alloys, optimization, regression equations, oxide film, technological ductility, heat resistance, durability.