Study On Preparation And Aging Treatment Technology Of Moderate Strength Aluminum Alloy Overhead Conductors

Based on the current situation of research and production development of moderate strength all-aluminum overhead conductors in China, this subject is a part work of "production technology development of the aluminum alloy conductor wire", which cooperated with the Shaoxing power equipment company. The main content of this work is to study the structure and property evolution of the aluminum alloy conductor wire during production process, and the effect of aging process on the property of the aluminum alloy conductor wire to provide technical support for the production process aluminum alloy conductor wire.The content of this study include structure and property evolution of the aluminum alloy conductor wire during production process, and the effect of aging process on the property of the aluminum alloy conductor wire. The main results are presented as followings:(1) During the13pass continuous rolling, the cast grain was elongated along the rolling direction gradually, and became fibrous deformation structure after rolling by13passes. The Vickers hardness of the billet gradually increased during the continuous rolling process, the hardness was increased from48.5HV to67.0HV after13passes rolling. Fibrous deformation structure was further stretched and tensile strength was increased from158MPa(rolling state) to283.4MPa(drawing state) after the aluminum alloy rod drawed by11pass times. Electrical resistivity of the drawing wire is about30.90nΩ·m.(2) During aging at150℃, tensile strength of the drawing wire decreases first, then increases and then decreases again, with the aging time increase from2hours to24hours. During aging at160℃-190℃, tensile strength of the drawing wire decreases with the increasing of the aging time. Tensile strength of drawing wire decreased more quickly with aging time at the beginning stage of aging especially at high aging temperature. When the aging is same, the higher aging temperature will result in the more tensile strength loss of drawing wire.(3) During the aging at150癈-190℃, Electrical resistivity of the drawing wire decreases with the increasing of the aging time. Electrical resistivity of the drawing wire decreased more quickly with aging time at the beginning stage of aging especially at high aging temperature.(4)The tensile strength of drawing wire significantly decreased from283.6MPa to103.5MPa, the elongation rate significantly increased by3.9%to25.9%after solid solution treatment at560℃for1h.(5) During aging at170℃after solid solution treatment, the tensile strength of the drawing wire increases firstly, and then reach the peak value of168.3MPa when aging for20hours, the tensile strength decrease when aging time more then20hours. Both elongation rate and electrical resistivity of the drawing wire decrease with the aging time during aging at170℃. The elongation rate and electrical resistivity of the drawing wire are5.1%and29.00nΩ·m, respective, after aging at170℃for20hours.(6) Base on the effect of the aging treatment on the property of the aluminum alloy drawing wire, the actual operability in the factory and the production efficiency, a more reasonable aging treatment technology is aging at160℃for6-10hours.