Overview
ISO 5832-5:2022 - "Implants for surgery - Metallic materials - Part 5: Wrought cobalt-chromium-tungsten-nickel" specifies the required characteristics and corresponding test methods for wrought Co–Cr–W–Ni alloy intended for the manufacture of surgical implants. The standard covers chemical composition, microstructure, inclusion limits and tensile properties, and references specific test methods for verification. Note: tensile results taken from finished devices may not necessarily match the raw‑material limits in this document.
Key topics and requirements
- Scope: Defines requirements for wrought cobalt‑chromium‑tungsten‑nickel alloy used in surgical implants.
- Chemical composition (heat analysis): chromium 19.00–21.00%, tungsten 14.00–16.00%, nickel 9.00–11.00%, iron ≤3.00%, carbon 0.05–0.15%, manganese 1.00–2.00%, plus limits for Si, S, P and cobalt as balance.
- Microstructure:
- Grain size (annealed condition) measured per ISO 643: index 5 or finer.
- Inclusion content assessed per ISO 4967:2013 (Method A) with thin inclusion limits of 1.5 for sulfides, aluminates, silicates and globular oxides; thick inclusions allowed up to 1.0.
- Tensile properties (annealed condition): tensile strength Rm ≥ 860 MPa, yield/proof strength Rp0.2 ≥ 310 MPa, minimum elongation A ≥ 30%. Testing per ISO 6892‑1; retest rules are specified for failed specimens.
- Test methods and conformity: Tables in the standard map each requirement to recognized analytical or ISO test methods and describe sampling and retest procedures.
Applications and who uses this standard
ISO 5832-5 is used by:
- Medical device and implant manufacturers specifying raw materials for surgical implants.
- Material suppliers and foundries certifying wrought Co–Cr–W–Ni alloy heat analysis and microstructure.
- Quality assurance, regulatory and testing laboratories performing acceptance testing and certification.
- Design and R&D teams that need baseline material properties when selecting alloys for biocompatible implants.
Practical applications include specification and acceptance of metallic materials for load-bearing surgical components, where controlled composition, microstructure and mechanical properties are critical for performance and regulatory compliance.
Related standards
- ISO 643 - Micrographic determination of apparent grain size
- ISO 4967:2013 - Determination of non‑metallic inclusions (micrographic)
- ISO 6892-1 - Metallic materials - Tensile testing at room temperature
- Other parts of the ISO 5832 series for metallic implant materials
Keywords: ISO 5832-5, wrought cobalt-chromium-tungsten-nickel, implants for surgery, surgical implants, metallic materials, tensile properties, chemical composition, ISO 643, ISO 4967, ISO 6892-1.
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