Investigation of Metal Structure Formation During Ingotless Rolling-Extrusion of Aluminum and Its Alloys

Results are given for studies of the structure and properties of semi-finished products made of aluminum and alloys of the Al-REM system, prepared using ingotless rolling-extrusion and equal-channel angular extrusion. It is established that rods obtained by high-speed crystallization-deformation technology using the method of ingotless rolling-extrusion have a stable ultrafine subgrain structure, which makes it possible to use deformed semi-finished products from them as modifier rods and electrical wire for cable products. Experimental studies are conducted confirming the assumption that the initial structure of a modifying rod has an effect on the melt. At the same time, it is found that sizes and distribution density of additional cluster-based crystallization centers formed within the melt volume are inherited from the initial subgrain structure of the modifying rod made of aluminum or its alloys. At the same time, it is found that the introduction of 3–4% of such a master alloy rod with a diameter of 8–9 mm into a crystallizing aluminum ingot at a melt temperature of 700–720°C and a melt standing time of at least 5 minutes provides a stable modifying effect. Production parameters for manufacture of bars from aluminum alloys by the ingotless rolling-extrusion method are established: melt temperature 720°C; degree of deformation during rolling is not less than 50%, roll rotational speed is 8 rpm. Metallographic studies also show that subsequent severe plastic deformation by equal-channel angular extrusion of bars prepared by ingotless rolling-extrusion from an experimental alloy of the composition Al–0.2Zr–0.2Fe–0.4Mg makes it possible to achieve additional metal hardening due to grain size and structure refinement. and to obtain wire for electrical purposes with a high level of physical and mechanical properties.