Development And Application Of The Continuous Casting-Continuous Extrusion Preparation Technology For Aluminum Alloy Round Rod

Aluminum alloy round rod is the raw material of aluminum alloy wire, aluminum alloy pipe used for heat exchanger and aluminum alloy welding material. The key technology of producing these products is the preparation of aluminum alloy round rod. There are three methods for aluminum alloy round rod preparation at present:the continuous casting and rolling method, the horizontal continuous casting and drawing method, the vertical semi-continuous casting and extrusion method. In view of the present production and research situation of aluminum alloy round rod, the horizontal continuous casting-continuous extrusion preparation technology is put forward based on the characteristics of horizontal continuous casting and continuous extrusion. The micro structure and mechanical properties of aluminum alloy round rod and wire is analyzed by optical microscope (OM), transmission electron microscope (TEM), microhardness test, tensile test at room temperature and resistance performance test methods.In this paper, the process of horizontal continuous casting and continuous extrusion technology is optimized. The casting process is improved by optimizing the structure of copper crystallizer, adding on-line filter device and changing the casting furnace and the holding furnace door plank material. Thus the crystallization rate is increased and the grain size is refined. The grain size of horizontal continuous casting rod billet is less than level2. The temperature rising rate of the extrusion billet is reduced by decreasing the number and size of tank sealing blocks, which makes lower temperature extrusion come true. Since the extrusion speed is improved at certain temperature after the optimization, the production efficiency is improved.The effects of heat treatment process on the micro structure and properties of8030and6201aluminum alloy wires are studied. Along with the increase of annealing temperature or annealing time, the tensile strength and resistivity of8030aluminum alloy wires decreases significantly, while the elongation is improved obviously. Excessive extension of the annealing time is meaningless for8030aluminum alloy wire. The aging hardening rate of6201aluminum alloy wire increases as the artificial aging temperature raises but the peak aging hardness at higher temperature is lower than that of lower temperature. Under certain temperature, the tensile strength and hardness of6201aluminum alloy wire increases rapidly at first and then the increase rate slows down, they decrease after reaching the peak-aging. The elongation, as well as the resistivity decreases along with the extending of aging time.The using performance of aluminum alloy conductor and other aluminum alloy round rod produced by process of horizontal continuous casting-continuous extrusion can match or even exceed the traditional drawing or continuous casting and rolling process ones. The new preparation technology has properties of simple process, convenient operation, high yield and low production cost, it can be widely used for the development and production of electrical round aluminum rod, aluminum alloy round rod used in continuous extrusion and aluminum alloy solder rod material.