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Since 1970, Aluminum-clad steel wire have been produced at Berndorf. Aluminum-clad steel wire are high strength steel wires, coated with aluminum in an extruding procedure, and afterwards drawn during a hydrodynamic drawing process to their final diameter. Aluminum-clad steel wires are used as a substitute for galvanized steel in overhead lines, which are phase conductors, earth wires, fiber optic wires and conductors.
The use of high strength steel wires with a thick aluminum coating results in substantial advantages compared to conventional galvanized steel wires.
» Excellent corrosion resistance against industrial and sea water atmospheres.
» Lower electrical resistance for a given cross section, and thus lower transducer losses.
» Lower weight leads to lower sag and tower loads.
| :: Manufacture of aluminum-clad steel wire |
Aluminium coating conforming to standards.
Following a careful wire rod mold surface treatment aluminum under high pressure and temperature is pressed onto steel wire.
Drawing of the aluminum-clad steel wire
In order to obtain the cross section relationship, with the diameter reduction, despite the different characteristics of silgness and strength of aluminium and steel, a hydrodynamic drawing procedure is used. Thus an even deformation of both metals is achieved. The connection between aluminum and steel is strengthened. The wire exhibits a molecular connection of the two metals after the pulling process. Before winding, the drawn wire goes through a continuous in-line coating and diameter control.
ACS wires have the same degree of corrosion resistance due to their thick aluminum layers as aluminum wires of the same diameter. The higher corrosion resistance compared to galvanized steel wires results from the purity of the coating (99.5%). Numerous experiments here and abroad confirm these results.
Salt sprayed
| :: Mechanical characteristics |
The use of high strength steel and aluminum, gives substantial advantages compared to conventional wires.
| |
Units |
ACS |
STEEL |
Al |
AlMgSi |
| Density |
kg/dm3 |
6,59 |
7,78 |
2,70 |
2,70 |
| Tensile strength (min) |
MPa |
1340 |
1300 |
170 |
295 |
| Countinous endurance strength |
MPa |
1230 |
900 |
120 |
240 |
| Alongation |
% |
> 1,5 |
3,5 |
1,6 |
3,5 |
| Moduls of elasticity |
GPa |
162 |
207 |
60 |
60 |
| Coeficiant of linear exoansion |
1/°Cx10-6 |
13,0 |
11,5 |
23,0 |
23,0 |
| Breaking length |
km |
20,33 |
16,71 |
6,30 |
10,93 |
| Electrical conductivity |
S m / mm² |
11,79 |
5,21 |
35,38 |
30,74 |
| Resistance.temp.index |
1/°Cx10-3 |
3,6 |
4,8 |
4,0 |
3,6 |
| spec. heat |
J / g K |
0,607 |
0,544 |
0,963 |
0,963 |
| :: Electrical characteristics |
Ohm´ resistance
The thick aluminum layers very substantially affect the electrical conductivity.
Specific electrical resistance < 0.0848 Ohm mm² / m
Specific electric conductivity > 11.792 Siemens m/ mm²
The reduction in the resistance value obtained, thus leads to a reduction in the short circuit loss. The reduction in the load dependent losses increases the profitability of the energy transfer. As an order of magnitude, a saving of 5% to 15% can be assumed.
Comparison of the conductivity of ACS wires with other conductor materials.
Resistance
After measurements of ACSR/ACS cables it can be shown that the resistance is lower than ACSR cables of the same geometric structure. The improvement amounts to 4 – 10%.
Specific thermal capacity
c = 0,607 J / kg K
The higher heat receptiveness of the STALUM wire compared to steel wire, demonstrates clearly the higher maximum stress and the high resistance to short circuits associated with it. This can be further increased by a thicker aluminum layer.
Eddy current losses
The magnetizability of the steel causes additional eddy currents and eddy current losses in aluminum/steel cables. In STALUM wires, the magnetic current is strongly retrained.
| OPGW - earth wire |
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ACSR/ACS - wire
BACSR/ACS - wire
TACSR/ACS - wire
BTACSR/ACS - wire |
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| ACS strand |
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| Helical fittings |
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| Anchoring wires for towers and wires for fruit growing | |
