Finite Element Analysis And Experiment Of The Continuous Dynamic Ecae Forming Process Of AL-Mg-Si Alloy

High performance aluminum alloy conductor is an urgent need for electric power industry; it is a famous research project in the world. It has an important significance for saving energy and national economic development. The key problems in the industry are to improve the electrical conductivity and mechanical properties of aluminum alloy conductor. In recent years, it is found that the comprehensive performance of the aluminum alloy conductor is greatly improved by using ECAE forming process. However, the product-size of the aluminum alloy wires produced by ordinary ECAE forming process is small with discontinuity; it is of great significance to study the continuous ECAE dynamic forming process.The parts of “Precipitated- phase evolution and hardening mechanism of Aluminum alloy conductors prepared by continuous dynamic aging ECAE forming process(NO.51174139)” in the National Natural Science Foundation of China was studied in this paper. So the evolution of the precipitation phase evolution and the performance enhancement mechanism of the continuous ECAE dynamic process of Al-Mg-Si alloy wire is proposed to study in this paper. Being the complexity of the continuous dynamic ECAE dynamic forming process, computer simulation is first used and the distribution and variation of the mechanical properties of the different process parameters are obtained analyzed, the appropriate process parameters were obtained. Then the multi-passes were proceed. The influence of passes on stress-strain distribution of workpiece as well as temperature field studied and the optimum processing technology was determined. The microstructure, mechanical properties and electrical properties of Al-Mg-Si alloy were studied by means of optical microscope, tensile testing machine and double arm direct current bridge. The main results were as follows:(1) Defrom-3D software is used to simulate the influence of temperature, velocity and friction condition on the stress and strain and temperature distribution of single pass continuous ECAE dynamic forming process. The results show that the stress and strain and temperature distribution in the forming process are not homogeneous, and the optimal working conditions were the follow :temperature was at 220℃, the friction was 0.2 and the rotational speed was 10rpm;(2) Through computer simulation of multi-pass continuous ECAE dynamic forming process, the stress and strain and temperature field distribution of different pass were obtained. The effective strain and effective strain and temperature is increased and the distribution of them is more uniform with the pass increment, the uniform distribution is achieved best in the fourth pass. The optimal number of passes is four;(3) The Al-0.32%Mg-0.44%Si-0.06%Be-0.06%B contents alumina alloy was pre pared. The mold and the workpiece temperature was 220 ℃, pass number was 4, Al-0.32Mg-0.44 Si alloy grain refinement effect better, and the grain distribution is more uniform, and the simulation result is consistent;(4) Optimized heat treatment process The wire under 6 ~ 8 hours aging treated at 160℃ to 180℃ can get a good comprehensive performance, the wire tensile strength can reach about 295 MPa, stretching coefficient is about 3.7, the equivalent conductivity is about 57.1%IACS. More than half of the overall performance of the existing strength of aluminum magnesium silicon alloy wire. The comprehensive performance were improved about 10% than continuous casting and rolling process Al-Mg-Si alloy wire.