Comparative analysis of properties of wires from alloys of Al-REM system, obtained using the methods of continuous extrusion

Abstract

The article presents the results of experimental studies of the production technology of electrical wire made of aluminum alloy of the Al–REM system with content of rare earth metals in the range of 7-9% using continuous casting and extrusion processing methods. Continuous casting rods with a diameter of 12 mm, obtained by casting into an electromagnetic mold (EMM), were the starting material for research. Methods of continuous extrusion "Conform" and combined rolling-extrusion (CRE) were the main methods to obtain a billet for subsequent drawing. Deformation modes, methods of experiments and equipment for the implementation of two variants of the proposed technology using various methods of continuous extrusion described. At all stages of the technology, samples were taken and the mechanical and electrophysical properties of the obtained deformed semi-finished products (ultimate tensile strength, elongation to failure and electrical resistivity) were studied. Application of the "Conform" method in industrial conditions using standard drawing routes allows obtaining a wire of small diameters with high strength properties, however, the plastic properties and values of electrical resistance do not correspond to the existing requirements of the technical specifications for its production. On the contrary, the plastic properties of hot-extruded rods obtained by the CRE method allow cold deformation using only one intermediate annealing. At the same time, the developed technology using continuous casting, combined rolling-extrusion, drawing modes and final annealing of a wire with a diameter of 0.5 mm provides the required level of plastic and strength properties, as well as minimum values of electrical resistance. The developed modes of deformation and heat treatment can be recommended for the industrial production of electrotechnical wire from high-alloyed Al–REM alloys.