ASTM B711 defines requirements for manufacturing overhead electrical conductors comprising a composite structure:
Outer Strands: Round aluminum-alloy 6201-T81 wires (solution heat-treated, cold-worked, artificially aged to “hard” temper)
Core Reinforcement: Round steel wires with zinc-coated, aluminum-coated, or aluminum-clad surfaces
This standard ensures consistent mechanical and electrical properties for high-voltage transmission infrastructure.
Conductor Composition:
Aluminum-alloy wires must adhere to ANSI H35.1/Unified Numbering System A96201 (per Practice E527).
Steel core wires feature corrosion-resistant coatings (zinc, aluminum, or aluminum-clad).
Material Processing:
Aluminum alloy undergoes rigorous solution heat treatment → cold working → artificial aging.
Unit Exclusivity:
Values solely stated in SI units (no inch-pound equivalents included).
Wire Standards Compliance:
Aluminum-alloy 6201-T81 wires must meet hardness, strength, and conductivity benchmarks post-artificial aging.
Steel core wires must maintain coating integrity and tensile strength.
Metric Transition:
Future references to inch-pound standards will shift to metric equivalents (may necessitate minor value adjustments).
High Strength-to-Weight Ratio: Aluminum alloy (6201-T81) provides optimal conductivity, while steel reinforcement enhances mechanical durability.
Corrosion Resistance: Coated/Clad steel core offers long-term reliability in harsh environments.
Standardized Performance: Artificially aged alloy ensures predictable behavior under thermal/mechanical stress.
Primary Application: Overhead electrical conductors in high-voltage power transmission systems (≥69 kV).
Critical Use Cases:
Long-span river/canyon crossings requiring tensile strength.
Coastal grids exposed to salt spray (aluminum-clad steel core preferred).
Regions with extreme temperature fluctuations (aging process ensures stability).
