ASTM B910/B910M-07(2023) PDF

Overview

ASTM B910/B910M-07(2023) is the internationally recognized standard specification for annealed copper-clad steel wire. Developed by ASTM International, this standard details the requirements for bare, round copper-clad steel wire primarily used in electrical, electronic, grounding, and telecommunications applications. Copper-clad steel wire combines the high conductivity of copper with the strength of a steel core, making it an ideal solution in applications where both electrical performance and mechanical durability are required. The standard outlines four types of wire based on electrical conductivity and sets criteria for tensile strength, elongation, dimensions, adhesion, copper thickness, density, and electrical resistivity.

Key Topics

• Material Composition: The wire consists of a homogeneous steel core (open-hearth, electric-furnace, or basic-oxygen) with a continuously bonded copper cladding.
• Conductivity Types: Four minimum electrical conductivities are specified - 21%, 30%, 40%, and 70% International Annealed Copper Standard (IACS).
• Annealed Temper: All types are supplied in an annealed condition, ensuring flexibility and ease of handling.
• Dimensional Tolerance: The standard specifies precise diameter ranges and permissible variations to maintain quality across applications.
• Mechanical Properties: Requirements for tensile strength (ranging up to 50,000 psi) and elongation (minimum 15%) ensure the material performs reliably under mechanical and electrical loads.
• Quality and Surface Finish: The specification addresses adhesion of copper to steel, surface defects, joints (no joints/splices at finished size), finish, and inspection criteria to guarantee consistent product quality.
• Electrical Properties: Limits are set on electrical resistivity and minimum copper thickness, essential for predictable electrical performance.

Applications

Copper-clad steel wire manufactured to ASTM B910/B910M-07(2023) is widely utilized in:

• Electrical and Electronic Components: Used where high strength and good conductivity are required, such as in wire-wrapping, relay leads, and connectors.
• Grounding and Bonding: Ideal for grounding systems where corrosion resistance of copper and the strength of steel are needed.
• Telecommunications: Widely applied in overhead and underground wire for telephone and data lines due to its balance of conductivity, mechanical strength, and cost-effectiveness.
• Other Industrial Uses: Suitable for any application demanding reliable electrical performance combined with the robustness of steel and the corrosion resistance of copper, such as signal cables, antenna wires, and railway signaling.

Related Standards

• ASTM B193: Test Method for Resistivity of Electrical Conductor Materials - referenced for determining electrical resistivity.
• ASTM B258: Specification for Standard Nominal Diameters and Cross-Sectional Areas of AWG Sizes of Solid Round Wires - guides dimension specification.
• NIST/NBS Handbook 100: Copper Wire Tables - provides reference data for wire gauges and conductivity.

Practical Value

Conformance to ASTM B910/B910M-07(2023) ensures reliability, safety, and standardized quality for copper-clad steel wire in critical infrastructure. The specification’s clarity on electrical and mechanical requirements aids manufacturers in meeting industry expectations and ensures end-users receive wire that performs dependably in demanding environments. By standardizing measurement, inspection, and testing methods, this document supports global trade and interoperability in electrical and telecommunications markets.

Keywords: ASTM B910, copper-clad steel wire, annealed, electrical conductor, grounding wire, telecommunications wire, standard specification, mechanical properties, electrical resistivity, quality standards, ASTM International.