Overview
ISO 14811:2025 specifies requirements for ultra‑low carbon high boron steel wire rod for copper cladded wire, primarily intended for telecommunication cable cores. The standard covers wire rods with circular cross‑sections and diameters from 5 mm to 20 mm, defining designation, production, delivery condition, inspection and marking requirements for continuous hot‑rolled or heat‑treated coils.
Key topics and technical requirements
- Scope and designation
- Applies to steel wire rod used as a steel core with continuous copper cladding (copper cladded wire).
- Special designation format: CH#B (C = carbon, H = high, # = max C × 10 000, B = boron).
- Dimensions and tolerances
- Diameter range 5–20 mm with four standardized tolerance classes T1–T4 (per ISO 16124); out‑of‑roundness limits are specified for each class.
- Chemical composition
- Defines heat analysis ranges for grades CH1B, CH3B, CH5B, CH6B (ultra‑low carbon, controlled Si, Mn, P, S, Al, B, N per Table 2).
- Mechanical properties
- Tensile strength and elongation requirements are given by grade. Example:
- CH1B: Rm ≤ 320 MPa, A ≥ 40%
- CH3B: Rm 320–360 MPa, A 30–40%
- CH5B: Rm 360–400 MPa, A 25–30%
- CH6B: Rm 400–450 MPa, A 20–25%
- Conductivity
- Conductivity (% IACS) specified by grade (e.g., CH1B 17.5–19.0% IACS down to CH6B 12.0–14.0% IACS), measured per IEC 60468.
- Quality, inspection and testing
- Requirements for internal soundness, surface discontinuities, non‑metallic inclusion (optional) and allowable discontinuity depth (ref. ISO 16120‑4).
- Test methods and sampling reference ISO 377, ISO 6892‑1 (tensile), ISO 14284 (chemical analysis), IEC 60468 (conductivity).
- Production & delivery
- Steelmaking by BOF or EAF with refining (supplier discretion unless agreed).
- Supplied in single‑length coils, marking to include dimensions, grade, heat number, supplier, conductivity.
Applications and intended users
- Practical use: production of copper cladded wire for telecommunication cables, where a steel core provides strength and copper cladding provides conductivity and corrosion protection.
- Primary users:
- Steel mills and wire‑rod producers manufacturing CH#B grades.
- Cable manufacturers specifying core material for telecom and specialty wiring.
- Quality and inspection engineers ensuring conformity to mechanical, chemical and electrical requirements.
- Procurement and compliance teams referencing ISO 14811:2025 in purchase specifications.
Related standards
Keywords: ISO 14811:2025, ultra‑low carbon high boron steel, wire rod, copper cladded wire, telecommunication cable, conductivity, tensile strength, chemical composition, ISO standards.
