ISO 23475-1:2021 PDF

Overview - ISO 23475-1:2021 (Testing method for steel tyre cord - Part 1: General requirements)

ISO 23475-1:2021 specifies standardized test methods for steel cords used in tyre reinforcement. Part 1 provides the general requirements covering dimensional measurements, process properties, mechanical properties and coating characterization. The standard defines accepted test principles, apparatus, procedures, result expression and test report content to ensure consistent evaluation of steel tyre cord quality.

Key topics and technical requirements

The standard addresses a comprehensive set of test areas for steel tyre cord, including:

• Dimension

  • Cord diameter measurement methods (micrometre, profile projector)
  • Unravelled filament diameter, linear density, lay direction and lay length (trace and untwisting methods)

• Process properties

  • Straightness, arc height, flare and residual torsion with defined principles, apparatus and procedures

• Mechanical properties

  • Breaking load and elongation at fracture
  • Elongation between defined forces (EDF)
  • Loop (elasticity) test - each with test setup, execution and reporting requirements

• Coating mass and composition

  • Determination by X‑Ray fluorescence spectroscopy (WDXRFS or EDXRFS)
  • Sample preparation, reagents (e.g., acetone, ammonium persulphate, ammonia), stripping solution formulation, calibration standards, and reporting of results

The document references normative standards (for example, ISO 17832 for related terms) and follows ISO reporting conventions for traceability and reproducibility.

Practical applications and who uses this standard

ISO 23475-1 is directly applicable to organizations involved in tyre reinforcement materials and testing:

• Tyre manufacturers - for incoming material inspection and supplier qualification of steel cords.
• Steel wire and cord producers - to validate product specifications and maintain production quality.
• Independent testing laboratories - to perform accredited tests for compliance and certification.
• R&D and quality engineers - to compare materials, optimize cord designs and document test results consistently.
• Procurement and standards teams - to specify acceptance criteria and ensure conformity across suppliers.

Using ISO 23475-1 helps ensure consistent material performance, enhances interchangeability between suppliers, supports regulatory and contractual compliance, and reduces variability in tyre reinforcement performance.

Related standards

• ISO 23475 series (other parts as listed by ISO)
• ISO 17832 - referenced for terms and definitions relevant to steel wire and cords

Keywords: ISO 23475-1, steel tyre cord testing, tyre reinforcement, cord diameter, coating analysis, X‑Ray fluorescence, mechanical properties, process properties.