Corrosion resistance of aluminum alloy conductors

Aluminum alloy power conductor is a new type of material power cable that uses AA8030 series aluminum alloy material as the conductor and adopts special roll forming wire stranding production technology and annealing treatment. Alloy power cables make up for the shortcomings of pure aluminum cables in the past. Although the electrical conductivity of the cable is not improved, the bending performance, creep resistance and corrosion resistance are greatly improved, which can ensure that the cable remains continuous during long-term overload and overheating. The performance is stable. The use of AA-8030 series aluminum alloy conductors can greatly improve the conductivity and high temperature resistance of the aluminum alloy cable, while solving the problems of pure aluminum conductors and creep. The electrical conductivity of aluminum alloy is 61.8% of the most commonly used benchmark material copper IACS, and the current carrying capacity is 79% of copper, which is better than the pure aluminum standard. But under the same volume, the actual weight of aluminum alloy is about one-third of copper. Therefore, the weight of the aluminum alloy cable is about half of the copper cable at the same current carrying capacity. The use of aluminum alloy cables instead of copper cables can reduce the weight of the cable, reduce the installation cost, reduce the wear of the equipment and the cable, and make the installation work easier.

The inherent anti-corrosion performance of aluminum comes from the formation of a thin and strong oxide layer when the AAAC Conductor surface is in contact with air. This oxide layer is particularly resistant to various forms of corrosion. The rare earth elements added to the alloy can further improve the corrosion resistance of the aluminum alloy, especially the electrochemical corrosion. Aluminum’s ability to withstand harsh environments makes it widely used as conductors for cables in trays, as well as many industrial components and containers. Corrosion is usually related to the connection of different metals in a humid environment. Corresponding protective measures can be used to prevent corrosion, such as the use of lubricants, antioxidants and protective coatings. Alkaline soil and certain types of acidic soil environments are more corrosive to aluminum, so directly buried aluminum conductors should use insulating layers or molded sheaths to prevent corrosion. In sulfur-containing environments, such as railway tunnels and other similar places, the corrosion resistance of aluminum alloy is much better than that of copper.
Aluminum alloy has very good bending properties, and its unique alloy formula and processing technology greatly improve flexibility. Aluminum alloy is 30% more flexible than copper and has a 40% lower resilience than copper. Generally, the bending radius of copper cables is 10-20 times the outer diameter, while the bending radius of aluminum alloy cables is only 7 times the outer diameter, making it easier to connect terminals.
Armor characteristics
Commonly used armored cables are mostly armored with steel tape, with low security level. When subjected to external destructive forces, their resistance is poor, which is easy to cause breakdown, and the weight is heavy, the installation cost is quite high, and the corrosion resistance is poor. The life is not long. The metal interlocking armored cable we developed according to American standards uses aluminum alloy tape interlocking armor. The interlocking structure between layers ensures that the cable can withstand the powerful destructive force from the outside, even if the cable is subjected to greater pressure The cable is not easy to be punctured under the impact force, which improves the safety performance. At the same time, the armored structure isolates the cable from the outside world. Even in the event of a fire, the armored layer improves the flame-retardant and fire-resistant level of the cable and reduces the risk of fire. Compared with the steel tape armored structure, the aluminum alloy tape armored structure is lighter in weight, convenient to lay, and can be installed without bridges, which can reduce installation costs by 20% to 40%. According to the different places of use, different outer sheath layers can be selected, which makes the use of armored cables more extensive.

How to inspect Aluminum Alloy Cable ?

1.Coefficient of compression of wire core

Aluminum alloy cable and the traditional power cable process structure and auxiliary materials have certain differences, aluminum alloy cable conductor using aluminum alloy monofilament tightly pressed stranded way, its core compression coefficient reached 97%, the conductor is very dense, and the traditional copper-core cable, aluminum-core cable in the conductor cross-section can clearly see the difference (the traditional cable production process, the core of the tight pressure coefficient can only reach 82% or so).

2. Flexibility

Aluminum alloy cable using ASTM-B800 electrical control with 8000 series aluminum alloy wire, adding the appropriate amount of copper (Cu), iron (Fe), magnesium (Mg) … … and rare earth aluminum alloy materials and intermediate alloy materials developed through a special synthetic annealing process of high-tech new environmentally friendly energy-saving power cable, its conductor flexibility can be super strong, the Super flexibility can ensure the safety performance of aluminum alloy cable in actual application to reach or even surpass the copper-core cable, at the same time, it brings great advantages to the actual installation of aluminum alloy cable. In the actual test, direct hand folding test can get the aluminum alloy conductor is very flexible, it can be folded repeatedly or like a rope repeatedly winding, destructive folding aluminum alloy monofilament, experimental conclusion at least 18 times roundtrip before the crack or fracture phenomenon, while ordinary aluminum monofilament generally folded three times to crack, five times to absolutely break, an important disadvantage of ordinary aluminum wire is brittleness, in the As long as the installation of a certain angle of twisting, the conductor will have cracks, cracks will heat, corrosion, is an important cause of fire, which is also not times the universal application of the fatal reason.

3. Cable Structure

The aluminum alloy cable core adopts tightly pressed stranded way, the conductor cross-section is round core (traditional cable core more fan-shaped), the insulation adopts three-color co-extruded cross-linked polyethylene insulation process, the core arrangement rules, the whole cable round and flexible.

4.Bright and lustrous wire core

The aluminum alloy conductor has a bright and lustrous core cross section,such as overhead AAAC conductor 1/0 awg ,4/0 awg, which has a distinct organoleptic difference from conventional aluminum-core cables, due to the optimized crystallization of the conductor as a result of the rare earth alloys added during the smelting process.

5. Creep performance

The creep properties of the alloy conductor are almost identical to those of the copper core conductor, as shown by experiments: the yield strength of copper is 6.0, while that of the alloy conductor is 54, which is almost identical to that of copper, and 300% higher than that of the aluminum core conductor.

6. Extendibility

Elongation is an important indicator of the mechanical properties of the conductor, is an important symbol of the product and the size of the product can withstand external forces. It is also an important indicator for testing the mechanical properties of the cable bare conductor. Aluminum cable after annealing treatment of the elongation can reach 30%, while the elongation of copper cable for 30%, ordinary aluminum rod elongation of 15%, is an important indicator of the ability to replace the copper cable.

7. Tensile Strength

Since the density of aluminium alloys is only 30.4% of that of copper, even if the cross-sectional area of aluminium alloys is increased to 150% of the copper cross-sectional area, the weight of aluminium alloys is still 45% of that of copper, which means that the tensile strength of aluminium alloys is still lower than that of copper. Advantage. In large-span power projects, due to its specific gravity advantage, its tensile strength advantage in the equivalent premise is particularly prominent. It not only saves a large number of bridges and reduces the labor intensity of installation engineers, but also speeds up the installation process, saves construction time and greatly reduces the comprehensive installation cost.

8. Anti-corrosion performance

Aluminum alloy conductor itself has excellent anti-corrosion properties, the good anti-corrosion properties of aluminum alloy conductor from the inherent anti-corrosion properties of aluminum, its surface when in contact with the air, will immediately form a layer of about 2 ~ 4 μm thick layer of dense oxide film, this layer is very dense, especially resistant to all forms of corrosion, and thus has the characteristics of withstand the worst of the environment, in the actual service life of 10 years longer than copper cable. above. (The current domestic use of alloy cable time is not long, just 3 to 5 years, so from the domestic actually can not verify its actual service life. Can only refer to the actual use of foreign countries, on the current use of the European and American countries for 40 years, his actual service life is more durable than copper cable).

9. Electrical Performance

The resistivity of aluminum alloys is between aluminum and copper, slightly higher than aluminum and lower than copper, and an aluminum alloy conductor of the same length weighs only half as much as copper for the same cutoff current. If the conductivity of copper is 100%, the conductivity of the alloy conductor is about 62.5%, the specific gravity of the alloy is 2.7, and the specific gravity of copper is 8.9, then (8.9/2.7)×(0.612/1)=2, i.e., the resistance of 2 units of copper is the same as the resistance of 1 unit of mass of the alloy. The same cutoff current, resistance, and voltage losses as copper are achieved.