ISO 5832-4:2024

ISO 5832-4:2024 - Overview

ISO 5832-4:2024 specifies the chemical, mechanical and test requirements for cobalt‑chromium‑molybdenum casting alloy intended for the manufacture of surgical implants. The fourth edition updates the chemical composition and mechanical testing language and harmonizes the document with the ISO 5832 series. It covers the raw casting alloy and associated test methods, not the finished medical device (mechanical properties of finished implants can differ).

Key topics and technical requirements

• Scope: Characteristics and conformity test methods for cobalt‑chromium‑molybdenum casting alloy used in surgical implants.
• Chemical composition: Heat analysis shall comply with prescribed limits. Major elements (mass fraction ranges):
  • Chromium: 27.0–30.0%
  • Molybdenum: 5.0–7.0%
  • Nickel: ≤ 0.50%
  • Iron: ≤ 0.75%
  • Carbon: ≤ 0.35%
  • Other limits for Mn, Si, W, P, S, N, Al, Ti, B; cobalt balance
• Mechanical properties (tensile testing): When tested per Clause 6/ISO 6892‑1, minimum requirements include:
  • Minimum tensile strength (Rm,min): 665 MPa
  • Minimum proof/yield strength (Rp0.2,min): 450 MPa
  • Minimum elongation after fracture (Amin): 8%
• Test methods: Chemical analysis and tensile testing procedures are specified. Tensile tests reference ISO 6892‑1 (room temperature tensile testing). Requirements for retests and acceptance criteria are defined.
• Notes: The document emphasizes testing of the raw material (heat analysis and representative test pieces). Retest rules and possible re‑heat treatment are described if results fail.

Applications and who uses ISO 5832-4

• Primary users: implant manufacturers, casting foundries, metallurgists, quality and compliance engineers, medical device testing laboratories, and regulatory bodies.
• Practical applications: specification and acceptance of cobalt‑chromium‑molybdenum castings for hip, knee and other load‑bearing implant components; material procurement, quality control, batch release, and conformity assessment for surgical implant alloys.
• Benefits: ensures consistent alloy chemistry, documented mechanical performance, and harmonized test methods that support patient safety and regulatory compliance.

Related standards

• ISO 5832 series (other parts covering implant metallic materials)
• ISO 6892‑1 - Tensile testing of metallic materials (referenced test method)
• ASTM F75 (historical/specification alignment noted in the standard bibliography)

Keywords: ISO 5832-4, cobalt-chromium-molybdenum, casting alloy, surgical implants, implant materials, mechanical properties, chemical composition, ISO 6892-1, ASTM F75.