Technology development for obtaining titaniumcontaining bar ligature for aluminum alloy modification

Abstract

The paper provides the results of experimental studies on the development of a method for obtaining titanium-containing bar ligature, the study of its structure and modifying ability. The distinctive features of the new technology are the use of titanium sponge and/or titanium shavings as titanium raw materials, the primary alloying of aluminum with titanium, and then boron, titanium introduction in two stages: initially, 2/3 of titanium metal raw materials are dissolved in the aluminum melt, and the remaining amount is introduced after the potassium tetrafluoroborate reduction. Titanium sponge pre-impregnation with halide-containing flux and the use of a briquetted KBF4 + Al-powder mixture are also provided. The experimental technology for Al–Ti–B melt preparation is described, titanium and boron extraction into the ligature is calculated, ligature microstructure is investigated, and chemical and molecular compositions of resulting slags are determined. Deformation processing for bar ligature production was carried out by the method of direct extrolling that smoothed over cast structure defects. It was found that the use of high-speed crystallization-deformation in the combined direct extrolling process makes it possible to obtain alloying bars of a given diameter at minimal energy consumption with the required set of mechanical and operational properties. A quantitative modifying ability assessment of the experimental cast-iron ligature and the deformed cast-iron rod obtained by the direct extrolling method was carried out in comparison with the mass-produced cast-iron ligature produced by KBM Affilips (the Netherlands/Belgium). Based on theoretical and experimental studies, the composition and technology for producing Al–Ti–B modifying ligature using titanium sponge and/or shavings and potassium tetrafluoroborate containing 3.0±0.3 % titanium and 1.0±0.2 % boron as alloying additives have been developed that meet the aluminum ligature composition requirements.