Analysis of energy-force parameters of combined processing for receiving modifiing bars from Al-5Ti-1B alloy

Abstract

The results of theoretical and experimental research of energy- force parameters of the combined rolling-extrusion process (CRE) and combined casting and rolling-extrusion process (CCRE) of Al-5Ti-1B alloy bars are presented. It is proved that bars from this alloy have turned out to be the most effective modifiers for obtaining ingots from aluminum alloys, having fine-grained structure and the required level of mechanical properties. It’s become obvious, that the existing manufacturing process of long-dimensioned deformed semi-finished products performed at casting-rolling equipment and horizontal hydraulic extrusion press does not always give an opportunity to obtain high-quality products due to the appearance of cracks in the process of rolling, and increased energy-power loading of the equipment. New technologies of combined processing (CRE and CCRE) have been proposed. These technologies allow to reduce significantly the energy-force parameters of processing by means of using active frictional forces when combining casting, rolling and extrusion. According to the proposed formulas, the forces influencing the matrix and rolls during the combined processing have been calculated. These results have been compared to the experimental data, thus, the calculated and experimental data are of satisfactory convergence. Metallographic analysis of the structure of bars obtained by means of various methods of combined processing has been carried out. It has been pointed out, that the CCRE method gives an optimal arrangement and the range of intermetallic phases, while the particles are evenly distributed over the cross-section and are dispersed. The results of the tests of mechanical properties have demonstrated that the strength characteristics of the bars from the studied alloy are higher when the CRE process is implemented (temporary tear resistance is up to 213 MPa), while the plastic ones (relative elongation is up to 33.6%) are higher when implementing the CCRE process. The conclusion has been drawn that the CCRE method of manufacturing modifying bars from the Al-5Ti-1B alloy makes it possible to reduce the energy costs by a factor of 1.5-2 compared to the traditional processing methods; and to obtain an increased level of the plastic properties of the metal as well.