Research of Combined Process “Rolling-Pressing” Influence on the Microstructure and Mechanical Properties of Aluminium

Abstract

In the development of new technology forming the ultimate goal is increasing of productivity, expansion of range, creating a compact production, capable of rapid reconfiguration for mobile release of the new product. But the main purpose, of course, is improvement the quality of the source material. When used as a raw material of various grades of steel, non-ferrous metals and their alloys, the main aspect of quality improvement is increasing the strength characteristics. Often to increase the strength of deformable metal should be given reduced grain structure, up to subultra and even nano-level. There are several ways to obtain sub-ultra-fine-grain structure of metals and alloys, and one of those ways is a method of severe plastic deformation of the metal, implemented in the whole volume of the deformable metal.On the department "Plastic Metal Working" of Karaganda State Industrial University was previously developed and proposed a new method of combined rolling and pressing in equal-channel step die, which compared to conventional compression in the traditional equal-channel step die ensures the continuity of the process and removes the restrictions on the size of the original pieces. The essence of the method is that workpiece which is pre-heated to a temperature of the beginning of deformation is applied to the forming rolls, which due to contact friction forces captured it in roll gap and pushed through the channels of equal- channel step die. At the exit from the die installed a second pair of rolls, which pulls the workpiece from the die.In the research of the process were made theoretical studies, after which were received the empirical formulas to determine the rolling force in the rolls and pressing force in the matrix. Also were obtained formulas for the kinematic state of the process.Also conducted a simulation of the process in the software package Deform-3D, in which produced the picture of stress - strain state and analyzed the resulting force.In this work, laboratory studies were performed of the combined process. In particular, a laboratory experiment was conducted to implement the combined process of "rolling-compaction", whose main purpose was to research the effect of the scheme on the deformation changes in the microstructure and mechanical properties of the original pieces, made of aluminum alloy AK6.Research of the mechanical properties and microstructure of deformed aluminum billet by this way was found that the implementation of the combined process of "rolling-compression" increases strength properties of aluminum, and reduced plastic properties, and the original grain during deformation is reduced.