The Effects Of Alloying Elements Content And Processing Technology On Properties Of 8030 Aluminum Alloy

Our country is extremely poor in copper resources, but the consumption of copper is 21% of the world overall consumption and 80% of copper is reliant on imported produce, which lead to the price of copper rising rapidly. The consumption of copper resources in Wire and Cable is high. Therefore the significance of "Aluminum is used in place of copper" as a conductor of electricity is great.8030 aluminum alloy conductor is researched by foreign and already has been applied in civil use and Low Voltage Distribution of building 40 years, which have been proved safe, credible and inexpensive electric cable after several years of practice. But our country has not mastered this technique recently yet. Based on the analysis of foreign 8030 aluminum alloy conductor, the paper has studied Homogenizing Annealing of this aluminum alloy which can minimize Component Segregation, alloying element content, processing technology and heat treatment on the properties by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray diffractometry (EDX), which will provide an important basis for improving the performance of 8030 aluminum alloy conductor with self-owned intellectual property rights.The results show that the recrystallization grain size of foreign conductor is about 8～9μm; The major phase of the system is a-Al, accompanied with a little of second phases whose size is about 0.1～4μm, as Al6Fe、AkCu、Al9Si and so on; The morphology of second phases is long-cut, blocks, sphere and linear with boat-shape tip.The effects of Homogenizing Annealing on the As-cast Structure of 8030 aluminum alloy at 450℃,470℃and 500℃for 6h,12h,16h,20h,24h and 28h is respectively studied. The results show that serious dendrite segregation existing in the 8030 alloy ingot, and many eutectic phases with low melting-point exist along the grain boundary. Fe, Cu and Si elements distribute unevenly from the grain boundary to inside of the alloy. The non-equilibrium eutectic phases dissolve after homogenization on the As-cast Structure of alloy for (470℃,24 h), and the grain boundary becomes sparse and all alloying elements become more homogenized.The effects of alloying element content, processing technology and heat treatment on electrical conductivity, tensile strength and elongation are studied. The results show that the electrical conductivity of conductor is reduced with alloying element content increase, within the composition range determined by the standard of 8030 aluminum alloy; An intermediate annealing resulted in the decrease of electrical conductivity.The effects of annealing at 350℃～410℃through air cooling and furnace cooling on electrical conductivity is studied. The results show that the higher cooling rate, the lower electrical conductivity of alloy; The higher alloying element content, the lower electrical conductivity of alloy, through annealing of 350℃～410℃, the higher cooling rate, the lower electrical conductivity of alloy; Annealing of 300℃～350℃, The higher annealing temperature, the higher electrical conductivity of alloy; Annealing of 350℃～410℃, The higher annealing temperature, the lower electrical conductivity of alloy.The effects of annealing of 350℃through different annealing time on electrical conductivity are studied. The results show that the electrical conductivity of conductor whose alloying element content is Fe 0.36wt% Cu 0.152wt% is the highest, and the amount is 61.21% IACS* E; Tensile strength is decreased and electrical conductivity is incesased gradually as annealing time prolonging.The effects of quenching (500℃×1h) and aging (160℃×12h) on electrical conductivity, tensile strength and elongation is studied. The results show that aging makes a low electrical conductivity for 8030 aluminum alloy which has low alloying element content; But aging makes a high electrical conductivity for 8030 aluminum alloy which has high alloying element content; Tensile strength is decreased and electrical conductivity is incesased through aging.The effects of quenching (500℃×1h) and two-stage aging (100℃×8h)+ (160℃×12h), quenching (450℃×1h) andtwo-stage aging (100℃×8h)+(160℃×12h) on electrical conductivity, tensile strength and elongation is studied. The results show that electrical conductivity is higher for two-stage aging, especially quenching (450℃×1h) andtwo-stage aging (100℃×8h)+(160℃×12h); Tensile strength treated by quenching (500℃×1h) and two-stage aging (100℃×8h)+(160℃×12h) is lower than which treated by quenching (450℃×1h) and two-stage aging (100℃×8h)+ (160℃×12h) for 8030 aluminum alloy which has low alloying element content, but elongation is higher; Tensile strength and elongation treated by quenching (450℃×1h) and two-stage aging (100℃×8h)+(160℃×12h) are both increased.Electrical conductivity is affected by organization structure of material and the size, morphology, number and Distribution of second phases. So organization structure of conductor made in this research, properties reach the standard required and foreign conductor are comparatively analysed. The results show that the recrystallization grain sizes of conductor made in this research whose properties have reach the standard required are about 18pm, which are bigger than the grain sizes of foreign conductor, and the direction of grain is in accordance with direction of deformation, the morphology of second phases is long-cut, blocks and sphere; the second phases of conductor made in this research whose properties have not reach the standard required and whose grain sizes are about 17μm which sizes are about 2～6μm are not only big, but also have a great amount, meanwhile, the grain have no clear direction, however, there is not Al-Cu phase in the conductor; the sizes of the grain and the second phases of conductor whose properties have not reach the standard required are larger than that of foreign conductor; the grain of foreign conductor have no clear direction.